The MyODBC architecture is based on five components, as shown in the following diagram:

An ODBC Driver Manager is a library that manages communication between the ODBC-aware application and any drivers. Its main functionality includes:

Both Windows and Mac OS X include ODBC driver managers with the operating system. Most ODBC Driver Manager implementations also include an administration application that makes the configuration of DSN and drivers easier. Examples and information on these managers, including Unix ODBC driver managers are listed below:

Before installing the MyODBC drivers on Windows you should ensure that your Microsoft Data Access Components (MDAC) are up to date. You can obtain the latest version from the Microsoft Data Access and Storage website.

There are three available distribution types to use when installing for Windows. The contents in each case are identical, it is only the installation method which is different.

An error occurred while copying C:\WINDOWS\SYSTEM\MFC30.DLL. 
Restart Windows and try installing again (before running any
applications which use ODBC)

There are two methods available for installing MyODBC on Unix from a binary distribution. For most Unix environments you will need to use the tarball distribution. For Linux systems, there is also an RPM distribution available.

shell> su root
shell> gunzip MyODBC-3.51.11-i686-pc-linux.tar.gz
shell> tar xvf MyODBC-3.51.11-i686-pc-linux.tar
shell> cd MyODBC-3.51.11-i686-pc-linux

shell> cp libmyodbc* /usr/local/lib
shell> cp odbc.ini /usr/local/etc
shell> export ODBCINI=/usr/local/etc/odbc.ini

shell> su root
 shell> rpm -ivh MyODBC-3.51.12.i386.rpm

shell> su root
shell> rpm -Uvh MyODBC-3.51.12.i386.rpm

shell> su root
shell> rpm -e MyODBC

Mac OS X is based on the FreeBSD operating system, and you can normally use the MySQL network port for connecting to MySQL servers on other hosts. Installing the MyODBC driver enables you to connect to MySQL databases on any platform through the ODBC interface. You should only need to install the MyODBC driver when your application requires an ODBC interface. Applications that require or can use ODBC (and therefore the MyODBC driver) include ColdFusion, Filemaker Pro, 4th Dimension and many other applications.

Mac OS X includes its own ODBC manager, based on the iODBC manager. Mac OS X includes an administration tool that provides easier administration of ODBC drivers and configuration, updating the underlying iODBC configuration files.

You should only need to install MyODBC from source on Windows if you want to change or modify the source or installation. If you are unsure whether to install from source, please use the binary installation detailed in Section 23.1.2.3.1, “Installing MyODBC from a Binary Distribution on Windows”.

Installing MyODBC from source on Windows requires a number of different tools and packages:

C:\> cd samples
C:\> nmake -f Makefile all

You need the following tools to build MySQL from source on Unix:

Once you have all the required files, unpack the source files to a separate directory, you then have to run configure and build the library using make.

shell> ./configure --help

shell> ./configure --prefix=/usr/local \
         --with-iodbc=/usr/local \
         --with-mysql-path=/usr/local/mysql

shell> make

--without-server --enable-shared

shell> cd MyODBC-3.51.01
shell> make
shell> cd driver
shell> CC=/usr/bin/gcc \
          $CC -bundle -flat_namespace -undefined error \
          -o .libs/libmyodbc3-3.51.01.so \
          catalog.o connect.o cursor.o dll.o error.o execute.o \
          handle.o info.o misc.o myodbc3.o options.o prepare.o \
          results.o transact.o utility.o \
          -L/usr/local/mysql/lib/mysql/ \
          -L/usr/local/iodbc/lib/ \
          -lz -lc -lmysqlclient -liodbcinst

shell> cd .libs
shell> cp libmyodbc3-3.51.01.so /usr/local/lib
shell> cd /usr/local/lib
shell> ln -s libmyodbc3-3.51.01.so libmyodbc3.so

shell> CC=/usr/bin/gcc \
          $CC -bundle -flat_namespace -undefined error
          -o .libs/libmyodbc3_r-3.51.01.so
          catalog.o connect.o cursor.o dll.o error.o execute.o
          handle.o info.o misc.o myodbc3.o options.o prepare.o
          results.o transact.o utility.o
          -L/usr/local/mysql/lib/mysql/
          -L/usr/local/iodbc/lib/
          -lz -lc -lmysqlclient_r -liodbcinst

shell> make install

shell> make test

shell> ./configure --prefix=/usr/local
          --with-unixODBC=/usr/local
          --with-mysql-path=/usr/local/mysql
          --disable-shared
          --enable-gui=no
          --host=powerpc-apple

shell> make
shell> cd driver
shell> CC=/usr/bin/gcc \
          $CC -bundle -flat_namespace -undefined error
          -o .libs/libmyodbc3-3.51.01.so *.o
          -L/usr/local/mysql/lib/
          -L/usr/local/iodbc/lib
          -liodbcinst -lmysqlclient -lz -lc

shell> CC=/usr/bin/gcc \
          $CC -bundle -flat_namespace -undefined error
          -o .libs/libmyodbc3-3.51.01.so *.o
          -L/usr/local/mysql/lib/
          -L/usr/local/iodbc/lib
          -liodbcinst -lmysqlclienti_r -lz -lc -lpthread

shell> otool -LD .libs/libmyodbc3-3.51.01.so

shell> CC="cc" \
          CFLAGS="+z" \
          LDFLAGS="-Wl,+b:-Wl,+s" \
          ./configure --prefix=/usr/local
          --with-unixodbc=/usr/local
          --with-mysql-path=/usr/local/mysql/lib/mysql
          --enable-shared
          --enable-thread-safe

shell> CC="gcc" \
          LDFLAGS="-Wl,+b:-Wl,+s" \
          ./configure --prefix=/usr/local
          --with-unixodbc=/usr/local
          --with-mysql-path=/usr/local/mysql
          --enable-shared
          --enable-thread-safe

shell> ./configure --prefix=/usr/local
          --with-unixodbc=/usr/local
          --with-mysql-path=/usr/local/mysql
          --disable-shared
          --enable-thread-safe

Caution: You should read this section only if you are interested in helping us test our new code. If you just want to get MySQL Connector/ODBC up and running on your system, you should use a standard release distribution.

To be able to access the MyODBC source tree, you must have Subversion installed. Subversion is freely available from http://subversion.tigris.org/.

To build from the source trees, you need the following tools:

The most recent development source tree is available from our public Subversion trees at http://dev.mysql.com/tech-resources/sources.html.

To checkout out the Connector/ODBC sources, change to the directory where you want the copy of the MyODBC tree to be stored, then use the following command:

shell> svn co http://svn.mysql.com/svnpublic/connector-odbc3

You should now have a copy of the entire MyODBC source tree in the directory connector-odbc3. To build from this source tree on Unix or Linux follow these steps:

shell> cd connector-odbc3
shell> aclocal
shell> autoheader
shell> autoconf
shell> automake;
shell> ./configure  # Add your favorite options here
shell> make

For more information on how to build, refer to the INSTALL file located in the same directory. For more information on options to configure, see Section 23.1.2.4.2.1, “Typical configure Options”

When the build is done, run make install to install the MyODBC 3.51 driver on your system.

If you have gotten to the make stage and the distribution does not compile, please report it to <myodbc@lists.mysql.com>.

On Windows, make use of Windows Makefiles WIN-Makefile and WIN-Makefile_debug in building the driver. For more information, see Section 23.1.2.4.1, “Installing MyODBC from a Source Distribution on Windows”.

After the initial checkout operation to get the source tree, you should run svn update periodically update your source according to the latest version.

To add and configure a new MyODBC data source on Windows, use the ODBC Data Source Administrator:

A completed DSN configuration may look like this:

You can verify the connection using the parameters you have entered by clicking the Test button. If the connection could be made successfully, you will be notified with a Success; connection was made! dialog.

If the connection failed, you can obtain more information on the test and why it may have failed by clicking the Diagnostics... button to show additional error messages.

You can configure a number of options for a specific DSN by using either the Connect Options or Advanced tabs in the DSN configuration dialog.

The Connection Options dialog can be seen below.

The three options you can configure are:

The Advanced tab enables you to configure MyODBC connection parameters. Refer to Section 23.1.3.5, “MyODBC Connection Parameters”, for information about the meaning of these options.

This section answers MyODBC connection-related questions.

To enable the trace option on Windows:

To enable the trace option on Mac OS X 10.3 or later you should use the Tracing tab within ODBC Administrator .

To enable the trace option on Mac OS X 10.2 (or earlier) or Unix you must add the trace option to the ODBC configuration:

To generate a MyODBC log, do the following:

If you need help determining what is wrong, see Section 23.1.7.1, “MyODBC Community Support”.

MyODBC has been tested with the following applications:

If you know of any other applications that work with MyODBC, please send mail to <myodbc@lists.mysql.com> about them.

You can use Microsoft Word and Microsoft Excel to access information from a MySQL database using MyODBC. Within Microsoft Word, this facility is most useful when importing data for mailmerge, or for tables and data to be included in reports. Within Microsoft Excel, you can execute queries on your MySQL server and import the data directly into an Excel Worksheet, presenting the data as a series of rows and columns.

With both applications, data is accessed and imported into the application using Microsoft Query , which enables you to execute a query though an ODBC source. You use Microsoft Query to build the SQL statement to be executed, selecting the tables, fields, selection criteria and sort order. For example, to insert information from a table in the World test database into an Excel spreadsheet, using the DSN samples shown in Section 23.1.3, “MyODBC Configuration”:

The same process can be used to import data into a Word document, where the data will be inserted as a table. This can be used for mail merge purposes (where the field data is read from a Word table), or where you want to include data and reports within a report or other document.

You can use MySQL database with Microsoft Access using MyODBC. The MySQL database can be used as an import source, an export source, or as a linked table for direct use within an Access application, so you can use Access as the front-end interface to a MySQL database.

This section contains simple examples of the use of MySQL ODBC 3.51 Driver with ADO, DAO and RDO.

Private Sub myodbc_ado_Click()

Dim conn As ADODB.Connection
Dim rs As ADODB.Recordset
Dim fld As ADODB.Field
Dim sql As String

'connect to MySQL server using MySQL ODBC 3.51 Driver
Set conn = New ADODB.Connection
conn.ConnectionString = "DRIVER={MySQL ODBC 3.51 Driver};"_
& "SERVER=localhost;"_
& " DATABASE=test;"_
& "UID=venu;PWD=venu; OPTION=3"

conn.Open

'create table
conn.Execute "DROP TABLE IF EXISTS my_ado"
conn.Execute "CREATE TABLE my_ado(id int not null primary key, name varchar(20)," _
& "txt text, dt date, tm time, ts timestamp)"

'direct insert
conn.Execute "INSERT INTO my_ado(id,name,txt) values(1,100,'venu')"
conn.Execute "INSERT INTO my_ado(id,name,txt) values(2,200,'MySQL')"
conn.Execute "INSERT INTO my_ado(id,name,txt) values(3,300,'Delete')"

Set rs = New ADODB.Recordset
rs.CursorLocation = adUseServer

'fetch the initial table ..
rs.Open "SELECT * FROM my_ado", conn
Debug.Print rs.RecordCount
rs.MoveFirst
Debug.Print String(50, "-") & "Initial my_ado Result Set " & String(50, "-")
For Each fld In rs.Fields
Debug.Print fld.Name,
Next
Debug.Print

Do Until rs.EOF
For Each fld In rs.Fields
Debug.Print fld.Value,
Next
rs.MoveNext
Debug.Print
Loop
rs.Close

'rs insert
rs.Open "select * from my_ado", conn, adOpenDynamic, adLockOptimistic
rs.AddNew
rs!Name = "Monty"
rs!txt = "Insert row"
rs.Update
rs.Close

'rs update
rs.Open "SELECT * FROM my_ado"
rs!Name = "update"
rs!txt = "updated-row"
rs.Update
rs.Close

'rs update second time..
rs.Open "SELECT * FROM my_ado"
rs!Name = "update"
rs!txt = "updated-second-time"
rs.Update
rs.Close

'rs delete
rs.Open "SELECT * FROM my_ado"
rs.MoveNext
rs.MoveNext
rs.Delete
rs.Close

'fetch the updated table ..
rs.Open "SELECT * FROM my_ado", conn
Debug.Print rs.RecordCount
rs.MoveFirst
Debug.Print String(50, "-") & "Updated my_ado Result Set " & String(50, "-")
For Each fld In rs.Fields
Debug.Print fld.Name,
Next
Debug.Print

Do Until rs.EOF
For Each fld In rs.Fields
Debug.Print fld.Value,
Next
rs.MoveNext
Debug.Print
Loop
rs.Close
conn.Close
End Sub

Private Sub myodbc_dao_Click()

Dim ws As Workspace
Dim conn As Connection
Dim queryDef As queryDef
Dim str As String

'connect to MySQL using MySQL ODBC 3.51 Driver
Set ws = DBEngine.CreateWorkspace("", "venu", "venu", dbUseODBC)
str = "odbc;DRIVER={MySQL ODBC 3.51 Driver};"_
& "SERVER=localhost;"_
& " DATABASE=test;"_
& "UID=venu;PWD=venu; OPTION=3"
Set conn = ws.OpenConnection("test", dbDriverNoPrompt, False, str)

'Create table my_dao
Set queryDef = conn.CreateQueryDef("", "drop table if exists my_dao")
queryDef.Execute

Set queryDef = conn.CreateQueryDef("", "create table my_dao(Id INT AUTO_INCREMENT PRIMARY KEY, " _
& "Ts TIMESTAMP(14) NOT NULL, Name varchar(20), Id2 INT)")
queryDef.Execute

'Insert new records using rs.addNew
Set rs = conn.OpenRecordset("my_dao")
Dim i As Integer

For i = 10 To 15
rs.AddNew
rs!Name = "insert record" & i
rs!Id2 = i
rs.Update
Next i
rs.Close

'rs update..
Set rs = conn.OpenRecordset("my_dao")
rs.Edit
rs!Name = "updated-string"
rs.Update
rs.Close

'fetch the table back...
Set rs = conn.OpenRecordset("my_dao", dbOpenDynamic)
str = "Results:"
rs.MoveFirst
While Not rs.EOF
str = " " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2
Debug.Print "DATA:" & str
rs.MoveNext
Wend

'rs Scrolling
rs.MoveFirst
str = " FIRST ROW: " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2
Debug.Print str

rs.MoveLast
str = " LAST ROW: " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2
Debug.Print str

rs.MovePrevious
str = " LAST-1 ROW: " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2
Debug.Print str

'free all resources
rs.Close
queryDef.Close
conn.Close
ws.Close

End Sub

Dim rs As rdoResultset
Dim cn As New rdoConnection
Dim cl As rdoColumn
Dim SQL As String

'cn.Connect = "DSN=test;"
cn.Connect = "DRIVER={MySQL ODBC 3.51 Driver};"_
& "SERVER=localhost;"_
& " DATABASE=test;"_
& "UID=venu;PWD=venu; OPTION=3"

cn.CursorDriver = rdUseOdbc
cn.EstablishConnection rdDriverPrompt


'drop table my_rdo
SQL = "drop table if exists my_rdo"
cn.Execute SQL, rdExecDirect

'create table my_rdo
SQL = "create table my_rdo(id int, name varchar(20))"
cn.Execute SQL, rdExecDirect

'insert - direct
SQL = "insert into my_rdo values (100,'venu')"
cn.Execute SQL, rdExecDirect

SQL = "insert into my_rdo values (200,'MySQL')"
cn.Execute SQL, rdExecDirect

'rs insert
SQL = "select * from my_rdo"
Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
rs.AddNew
rs!id = 300
rs!Name = "Insert1"
rs.Update
rs.Close

'rs insert
SQL = "select * from my_rdo"
Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
rs.AddNew
rs!id = 400
rs!Name = "Insert 2"
rs.Update
rs.Close

'rs update
SQL = "select * from my_rdo"
Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
rs.Edit
rs!id = 999
rs!Name = "updated"
rs.Update
rs.Close

'fetch back...
SQL = "select * from my_rdo"
Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
Do Until rs.EOF
For Each cl In rs.rdoColumns
Debug.Print cl.Value,
Next
rs.MoveNext
Debug.Print
Loop
Debug.Print "Row count="; rs.RowCount

'close
rs.Close
cn.Close

End Sub

This section contains simple examples that demonstrate the use of MyODBC drivers with ODBC.NET.

/**
 * @sample    : mycon.cs
 * @purpose   : Demo sample for ODBC.NET using MyODBC
 * @author    : Venu, <myodbc@lists.mysql.com>
 *
 * (C) Copyright MySQL AB, 1995-2006
 *
 **/
          
/* build command
 *
 *  csc /t:exe
 *      /out:mycon.exe mycon.cs
 *      /r:Microsoft.Data.Odbc.dll
 */
          
using Console = System.Console;
using Microsoft.Data.Odbc;
          
namespace myodbc3
{
  class mycon
  {
    static void Main(string[] args)
    {
      try
        {
          //Connection string for MyODBC 2.50
          /*string MyConString = "DRIVER={MySQL};" +
            "SERVER=localhost;" +
            "DATABASE=test;" +
            "UID=venu;" +
            "PASSWORD=venu;" +
            "OPTION=3";
          */
          //Connection string for MyODBC 3.51
          string MyConString = "DRIVER={MySQL ODBC 3.51 Driver};" +
            "SERVER=localhost;" +
            "DATABASE=test;" +
            "UID=venu;" +
            "PASSWORD=venu;" +
            "OPTION=3";
          
          //Connect to MySQL using MyODBC
          OdbcConnection MyConnection = new OdbcConnection(MyConString);
          MyConnection.Open();
          
          Console.WriteLine("\n !!! success, connected successfully !!!\n");
          
          //Display connection information
          Console.WriteLine("Connection Information:");
          Console.WriteLine("\tConnection String:" + 
                            MyConnection.ConnectionString);
          Console.WriteLine("\tConnection Timeout:" + 
                            MyConnection.ConnectionTimeout);
          Console.WriteLine("\tDatabase:" + 
                            MyConnection.Database);
          Console.WriteLine("\tDataSource:" + 
                            MyConnection.DataSource);
          Console.WriteLine("\tDriver:" + 
                            MyConnection.Driver);
          Console.WriteLine("\tServerVersion:" + 
                            MyConnection.ServerVersion);
          
          //Create a sample table
          OdbcCommand MyCommand = 
            new OdbcCommand("DROP TABLE IF EXISTS my_odbc_net",
                            MyConnection);
          MyCommand.ExecuteNonQuery();
          MyCommand.CommandText = 
            "CREATE TABLE my_odbc_net(id int, name varchar(20), idb bigint)";
          MyCommand.ExecuteNonQuery();
          
          //Insert
          MyCommand.CommandText = 
            "INSERT INTO my_odbc_net VALUES(10,'venu', 300)";
          Console.WriteLine("INSERT, Total rows affected:" + 
                            MyCommand.ExecuteNonQuery());;
          
          //Insert
          MyCommand.CommandText = 
            "INSERT INTO my_odbc_net VALUES(20,'mysql',400)";
          Console.WriteLine("INSERT, Total rows affected:" + 
                            MyCommand.ExecuteNonQuery());
          
          //Insert
          MyCommand.CommandText = 
            "INSERT INTO my_odbc_net VALUES(20,'mysql',500)";
          Console.WriteLine("INSERT, Total rows affected:" + 
                            MyCommand.ExecuteNonQuery());
          
          //Update
          MyCommand.CommandText = 
            "UPDATE my_odbc_net SET id=999 WHERE id=20";
          Console.WriteLine("Update, Total rows affected:" + 
                            MyCommand.ExecuteNonQuery());
          
          //COUNT(*)
          MyCommand.CommandText = 
            "SELECT COUNT(*) as TRows FROM my_odbc_net";
          Console.WriteLine("Total Rows:" + 
                            MyCommand.ExecuteScalar());
          
          //Fetch
          MyCommand.CommandText = "SELECT * FROM my_odbc_net";
          OdbcDataReader MyDataReader;
          MyDataReader =  MyCommand.ExecuteReader();
          while (MyDataReader.Read())
            {
              if(string.Compare(MyConnection.Driver,"myodbc3.dll") == 0) {
                //Supported only by MyODBC 3.51
                Console.WriteLine("Data:" + MyDataReader.GetInt32(0) + " " +
                                  MyDataReader.GetString(1) + " " +
                                  MyDataReader.GetInt64(2)); 
              }
              else {
                //BIGINTs not supported by MyODBC
                Console.WriteLine("Data:" + MyDataReader.GetInt32(0) + " " +
                                  MyDataReader.GetString(1) + " " +
                                  MyDataReader.GetInt32(2)); 
              }
            }
          
          //Close all resources
          MyDataReader.Close();
          MyConnection.Close();
        }
      catch (OdbcException MyOdbcException) //Catch any ODBC exception ..
        {
          for (int i=0; i < MyOdbcException.Errors.Count; i++)
            {
              Console.Write("ERROR #" + i + "\n" +
                            "Message: " + 
                            MyOdbcException.Errors[i].Message + "\n" +
                            "Native: " + 
                            MyOdbcException.Errors[i].NativeError.ToString() + "\n" +
                            "Source: " + 
                            MyOdbcException.Errors[i].Source + "\n" +
                            "SQL: " + 
                            MyOdbcException.Errors[i].SQLState + "\n");
            }
        }
    }
  }
}

' @sample    : myvb.vb
' @purpose   : Demo sample for ODBC.NET using MyODBC
' @author    : Venu, <myodbc@lists.mysql.com>
'
' (C) Copyright MySQL AB, 1995-2006
'
'

'
' build command
'
' vbc /target:exe
'     /out:myvb.exe
'     /r:Microsoft.Data.Odbc.dll
'     /r:System.dll
'     /r:System.Data.dll
'

Imports Microsoft.Data.Odbc
Imports System

Module myvb
  Sub Main()
    Try

      'MyODBC 3.51 connection string
      Dim MyConString As String = "DRIVER={MySQL ODBC 3.51 Driver};" & _
      "SERVER=localhost;" & _
      "DATABASE=test;" & _
      "UID=venu;" & _
      "PASSWORD=venu;" & _
      "OPTION=3;"

      'Connection
      Dim MyConnection As New OdbcConnection(MyConString)
      MyConnection.Open()

      Console.WriteLine("Connection State::" & MyConnection.State.ToString)

      'Drop
      Console.WriteLine("Dropping table")
      Dim MyCommand As New OdbcCommand()
      MyCommand.Connection = MyConnection
      MyCommand.CommandText = "DROP TABLE IF EXISTS my_vb_net"
      MyCommand.ExecuteNonQuery()

      'Create
      Console.WriteLine("Creating....")
      MyCommand.CommandText = "CREATE TABLE my_vb_net(id int, name varchar(30))"
      MyCommand.ExecuteNonQuery()

      'Insert
      MyCommand.CommandText = "INSERT INTO my_vb_net VALUES(10,'venu')"
      Console.WriteLine("INSERT, Total rows affected:" & _
      MyCommand.ExecuteNonQuery())

      'Insert
      MyCommand.CommandText = "INSERT INTO my_vb_net VALUES(20,'mysql')"
      Console.WriteLine("INSERT, Total rows affected:" & _
      MyCommand.ExecuteNonQuery())

      'Insert
      MyCommand.CommandText = "INSERT INTO my_vb_net VALUES(20,'mysql')"
      Console.WriteLine("INSERT, Total rows affected:" & _
      MyCommand.ExecuteNonQuery())

      'Insert
      MyCommand.CommandText = "INSERT INTO my_vb_net(id) VALUES(30)"
      Console.WriteLine("INSERT, Total rows affected:" & _
                        MyCommand.ExecuteNonQuery())

      'Update
      MyCommand.CommandText = "UPDATE my_vb_net SET id=999 WHERE id=20"
      Console.WriteLine("Update, Total rows affected:" & _
      MyCommand.ExecuteNonQuery())

      'COUNT(*)
      MyCommand.CommandText = "SELECT COUNT(*) as TRows FROM my_vb_net"
      Console.WriteLine("Total Rows:" & MyCommand.ExecuteScalar())

      'Select
      Console.WriteLine("Select * FROM my_vb_net")
      MyCommand.CommandText = "SELECT * FROM my_vb_net"
      Dim MyDataReader As OdbcDataReader
      MyDataReader = MyCommand.ExecuteReader
      While MyDataReader.Read
        If MyDataReader("name") Is DBNull.Value Then
          Console.WriteLine("id = " & _
          CStr(MyDataReader("id")) & "  name = " & _
          "NULL")
        Else
          Console.WriteLine("id = " & _
          CStr(MyDataReader("id")) & "  name = " & _
          CStr(MyDataReader("name")))
        End If
      End While

      'Catch ODBC Exception
    Catch MyOdbcException As OdbcException
      Dim i As Integer
      Console.WriteLine(MyOdbcException.ToString)

      'Catch program exception
    Catch MyException As Exception
      Console.WriteLine(MyException.ToString)
    End Try
  End Sub

Obtaining the value of column that uses AUTO_INCREMENT after an INSERT statement can be achieved in a number of different ways. To obtain the value immediately after an INSERT, use a SELECT query with the LAST_INSERT_ID() function.

For example, using MyODBC you would execute two separate statements, the INSERT statement and the SELECT query to obtain the auto-increment value.

INSERT INTO tbl (auto,text) VALUES(NULL,'text');
SELECT LAST_INSERT_ID();

If you do not require the value within your application, but do require the value as part of another INSERT, the entire process can be handled by executing the following statements:

INSERT INTO tbl (auto,text) VALUES(NULL,'text');
INSERT INTO tbl2 (id,text) VALUES(LAST_INSERT_ID(),'text');

Certain ODBC applications (including Delphi and Access) may have trouble obtaining the auto-increment value using the previous examples. In this case, try the following statement as an alternative:

SELECT * FROM tbl WHERE auto IS NULL;

See Section 22.2.13.3, “How to Get the Unique ID for the Last Inserted Row”.

Support for the dynamic cursor is provided in MyODBC 3.51, but dynamic cursors are not enabled by default. You can enable this function within Windows by selecting the Enable Dynamic Cursor checkbox within the ODBC data Source Administrator.

On other platforms, you can enable the dynamic cursor by adding 32 to the OPTION value when creating the DSN.

The MyODBC driver has been optimized to provide very fast performance. If you experience problems with the performance of MyODBC, or notice a large amount of disk activity for simple queries, there are a number of aspects you should check:

For more information on how to set the query timeout on Microsoft Windows when executing queries through an ODBC connection, read the Microsoft knowledgebase document at http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B153756.

The majority of Microsoft applications have been tested with MyODBC, including Microsoft Office, Microsoft Access and the various programming languages supported within ASP and Microsoft Visual Studio.

If you have problem with MyODBC and your program also works with OLEDB, you should try the OLEDB driver.

Dim myconn As New ADODB.Connection
Dim myrs As New Recordset
Dim mySQL As String
Dim myrows As Long

myconn.Open "DSN=MyODBCsample"
mySQL = "SELECT * from user"
myrs.Source = mySQL
Set myrs.ActiveConnection = myconn
myrs.CursorLocation = adUseClient
myrs.Open
myrows = myrs.RecordCount

myrs.Close
myconn.Close

With all Borland applications where the Borland Database Engine (BDE) is used, follow these steps to improve compatibility:

fReg:= TRegistry.Create;
fReg.OpenKey('\Software\ODBC\ODBC.INI\DocumentsFab', True);
fReg.WriteString('Database', 'Documents');
fReg.WriteString('Description', ' ');
fReg.WriteString('Driver', 'C:\WINNT\System32\myodbc.dll');
fReg.WriteString('Flag', '1');
fReg.WriteString('Password', '');
fReg.WriteString('Port', ' ');
fReg.WriteString('Server', 'xmark');
fReg.WriteString('User', 'winuser');
fReg.OpenKey('\Software\ODBC\ODBC.INI\ODBC Data Sources', True);
fReg.WriteString('DocumentsFab', 'MySQL');
fReg.CloseKey;
fReg.Free;

Memo1.Lines.Add('DATABASE NAME=');
Memo1.Lines.Add('USER NAME=');
Memo1.Lines.Add('ODBC DSN=DocumentsFab');
Memo1.Lines.Add('OPEN MODE=READ/WRITE');
Memo1.Lines.Add('BATCH COUNT=200');
Memo1.Lines.Add('LANGDRIVER=');
Memo1.Lines.Add('MAX ROWS=-1');
Memo1.Lines.Add('SCHEMA CACHE DIR=');
Memo1.Lines.Add('SCHEMA CACHE SIZE=8');
Memo1.Lines.Add('SCHEMA CACHE TIME=-1');
Memo1.Lines.Add('SQLPASSTHRU MODE=SHARED AUTOCOMMIT');
Memo1.Lines.Add('SQLQRYMODE=');
Memo1.Lines.Add('ENABLE SCHEMA CACHE=FALSE');
Memo1.Lines.Add('ENABLE BCD=FALSE');
Memo1.Lines.Add('ROWSET SIZE=20');
Memo1.Lines.Add('BLOBS TO CACHE=64');
Memo1.Lines.Add('BLOB SIZE=32');

AliasEditor.Add('DocumentsFab','MySQL',Memo1.Lines);

The following information is taken from the ColdFusion documentation:

Use the following information to configure ColdFusion Server for Linux to use the unixODBC driver with MyODBC for MySQL data sources. Allaire has verified that MyODBC 2.50.26 works with MySQL 3.22.27 and ColdFusion for Linux. (Any newer version should also work.) You can download MyODBC at http://dev.mysql.com/downloads/connector/odbc/.

ColdFusion version 4.5.1 allows you to us the ColdFusion Administrator to add the MySQL data source. However, the driver is not included with ColdFusion version 4.5.1. Before the MySQL driver appears in the ODBC data sources drop-down list, you must build and copy the MyODBC driver to /opt/coldfusion/lib/libmyodbc.so.

The Contrib directory contains the program mydsn-xxx.zip which allows you to build and remove the DSN registry file for the MyODBC driver on ColdFusion applications.

For more information and guides on using ColdFusion and MyODBC, see the following external sites:

Open Office (http://www.openoffice.org) How-to: MySQL + OpenOffice. How-to: OpenOffice + MyODBC + unixODBC.

Sambar Server (http://www.sambarserver.info) How-to: MyODBC + SambarServer + MySQL.

You have to change it to output VARCHAR rather than ENUM, as it exports the latter in a manner that causes MySQL problems.

You should select the Return matching rows option.

The following properties are available:

The following methods are available:

The following example creates a MySqlCommand and a MySqlConnection. The MySqlConnection is opened and set as the Connection for the MySqlCommand. The example then calls ExecuteNonQuery, and closes the connection. To accomplish this, the ExecuteNonQuery is passed a connection string and a query string that is an SQL INSERT statement.

Public Sub InsertRow(myConnectionString As String)
    ' If the connection string is null, use a default.
    If myConnectionString = "" Then
        myConnectionString = "Database=Test;Data Source=localhost;User Id=username;Password=pass"
    End If
    Dim myConnection As New MySqlConnection(myConnectionString)
    Dim myInsertQuery As String = "INSERT INTO Orders (id, customerId, amount) Values(1001, 23, 30.66)"
    Dim myCommand As New MySqlCommand(myInsertQuery)
    myCommand.Connection = myConnection
    myConnection.Open()
    myCommand.ExecuteNonQuery()
    myCommand.Connection.Close()
End Sub

public void InsertRow(string myConnectionString) 
{
    // If the connection string is null, use a default.
    if(myConnectionString == "") 
    {
        myConnectionString = "Database=Test;Data Source=localhost;User Id=username;Password=pass";
    }
    MySqlConnection myConnection = new MySqlConnection(myConnectionString);
    string myInsertQuery = "INSERT INTO Orders (id, customerId, amount) Values(1001, 23, 30.66)";
    MySqlCommand myCommand = new MySqlCommand(myInsertQuery);
    myCommand.Connection = myConnection;
    myConnection.Open();
    myCommand.ExecuteNonQuery();
    myCommand.Connection.Close();
}

The following properties are available:

The following methods are available:

The following example uses the MySqlCommand, along MySqlDataAdapter and MySqlConnection, to select rows from a data source. The example is passed an initialized DataSet, a connection string, a query string that is an SQL SELECT statement, and a string that is the name of the database table. The example then creates a MySqlCommandBuilder.

  Public Shared Function SelectRows(myConnection As String, mySelectQuery As String, myTableName As String) As DataSet
        Dim myConn As New MySqlConnection(myConnection)
        Dim myDataAdapter As New MySqlDataAdapter()
        myDataAdapter.SelectCommand = New MySqlCommand(mySelectQuery, myConn)
        Dim cb As SqlCommandBuilder = New MySqlCommandBuilder(myDataAdapter)

        myConn.Open()

        Dim ds As DataSet = New DataSet
        myDataAdapter.Fill(ds, myTableName)

        ' Code to modify data in DataSet here 

        ' Without the MySqlCommandBuilder this line would fail.
        myDataAdapter.Update(ds, myTableName)

        myConn.Close()
    End Function 'SelectRows
    

    public static DataSet SelectRows(string myConnection, string mySelectQuery, string myTableName)
    {
      MySqlConnection myConn = new MySqlConnection(myConnection);
      MySqlDataAdapter myDataAdapter = new MySqlDataAdapter();
      myDataAdapter.SelectCommand = new MySqlCommand(mySelectQuery, myConn);
      MySqlCommandBuilder cb = new MySqlCommandBuilder(myDataAdapter);

      myConn.Open();

      DataSet ds = new DataSet();
      myDataAdapter.Fill(ds, myTableName);

      //code to modify data in DataSet here

      //Without the MySqlCommandBuilder this line would fail
      myDataAdapter.Update(ds, myTableName);

      myConn.Close();

      return ds;
    }  
    

The following properties are available:

The following methods are available:

The following example creates a MySqlCommand and a MySqlConnection. The MySqlConnection is opened and set as the Connection for the MySqlCommand. The example then calls ExecuteNonQuery, and closes the connection. To accomplish this, the ExecuteNonQuery is passed a connection string and a query string that is an SQL INSERT statement.

Public Sub InsertRow(myConnectionString As String)
    ' If the connection string is null, use a default.
    If myConnectionString = "" Then
        myConnectionString = "Database=Test;Data Source=localhost;User Id=username;Password=pass"
    End If
    Dim myConnection As New MySqlConnection(myConnectionString)
    Dim myInsertQuery As String = "INSERT INTO Orders (id, customerId, amount) Values(1001, 23, 30.66)"
    Dim myCommand As New MySqlCommand(myInsertQuery)
    myCommand.Connection = myConnection
    myConnection.Open()
    myCommand.ExecuteNonQuery()
    myCommand.Connection.Close()
End Sub
      

public void InsertRow(string myConnectionString) 
{
    // If the connection string is null, use a default.
    if(myConnectionString == "") 
    {
        myConnectionString = "Database=Test;Data Source=localhost;User Id=username;Password=pass";
    }
    MySqlConnection myConnection = new MySqlConnection(myConnectionString);
    string myInsertQuery = "INSERT INTO Orders (id, customerId, amount) Values(1001, 23, 30.66)";
    MySqlCommand myCommand = new MySqlCommand(myInsertQuery);
    myCommand.Connection = myConnection;
    myConnection.Open();
    myCommand.ExecuteNonQuery();
    myCommand.Connection.Close();
}

      

The following properties are available:

The following methods are available:

The following example creates a MySqlCommand and a MySqlConnection. The MySqlConnection is opened and set as the Connection for the MySqlCommand. The example then calls ExecuteNonQuery, and closes the connection. To accomplish this, the ExecuteNonQuery is passed a connection string and a query string that is an SQL INSERT statement.

Public Function SelectRows(dataSet As DataSet, connection As String, query As String) As DataSet
    Dim conn As New MySqlConnection(connection)
    Dim adapter As New MySqlDataAdapter()
    adapter.SelectCommand = new MySqlCommand(query, conn)
    adapter.Fill(dataset)
    Return dataset
End Function 

public DataSet SelectRows(DataSet dataset,string connection,string query) 
{
    MySqlConnection conn = new MySqlConnection(connection);
    MySqlDataAdapter adapter = new MySqlDataAdapter();
    adapter.SelectCommand = new MySqlCommand(query, conn);
    adapter.Fill(dataset);
    return dataset;
}   
  

The following properties are available:

The following methods are available:

The following example creates a MySqlConnection, a MySqlCommand, and a MySqlDataReader. The example reads through the data, writing it out to the console. Finally, the example closes the MySqlDataReader, then the MySqlConnection

Public Sub ReadMyData(myConnString As String)
    Dim mySelectQuery As String = "SELECT OrderID, CustomerID FROM Orders"
    Dim myConnection As New MySqlConnection(myConnString)
    Dim myCommand As New MySqlCommand(mySelectQuery, myConnection)
    myConnection.Open()
    Dim myReader As MySqlDataReader
    myReader = myCommand.ExecuteReader()
    ' Always call Read before accessing data.
    While myReader.Read()
        Console.WriteLine((myReader.GetInt32(0) & ", " & myReader.GetString(1)))
    End While
    ' always call Close when done reading.
    myReader.Close()
    ' Close the connection when done with it.
    myConnection.Close()
End Sub 'ReadMyData       
      

public void ReadMyData(string myConnString) {
    string mySelectQuery = "SELECT OrderID, CustomerID FROM Orders";
    MySqlConnection myConnection = new MySqlConnection(myConnString);
    MySqlCommand myCommand = new MySqlCommand(mySelectQuery,myConnection);
    myConnection.Open();
    MySqlDataReader myReader;
    myReader = myCommand.ExecuteReader();
    // Always call Read before accessing data.
    while (myReader.Read()) {
       Console.WriteLine(myReader.GetInt32(0) + ", " + myReader.GetString(1));
    }
    // always call Close when done reading.
    myReader.Close();
    // Close the connection when done with it.
    myConnection.Close();
 }     
      

The following properties are available:

The MySqlException class has no methods.

The following example generates a MySqlException due to a missing server, and then displays the exception.

Public Sub ShowException()
     Dim mySelectQuery As String = "SELECT column1 FROM table1"
     Dim myConnection As New MySqlConnection ("Data Source=localhost;Database=Sample;")
     Dim myCommand As New MySqlCommand(mySelectQuery, myConnection)

     Try
         myCommand.Connection.Open()
     Catch e As MySqlException
        MessageBox.Show( e.Message )
     End Try
 End Sub       
      

public void ShowException() 
{
   string mySelectQuery = "SELECT column1 FROM table1";
   MySqlConnection myConnection =
      new MySqlConnection("Data Source=localhost;Database=Sample;");
   MySqlCommand myCommand = new MySqlCommand(mySelectQuery,myConnection);

   try 
   {
      myCommand.Connection.Open();
   }
   catch (MySqlException e) 
   {
        MessageBox.Show( e.Message );
   }
}
    

The MySqlHelper class has no properties.

The following methods are available:

The following properties are available:

The following methods are available:

The following example creates a MySqlConnection and a MySqlTransaction. It also demonstrates how to use the BeginTransaction, Commit, and Rollback methods.

Public Sub RunTransaction(myConnString As String)
    Dim myConnection As New MySqlConnection(myConnString)
    myConnection.Open()
    
    Dim myCommand As MySqlCommand = myConnection.CreateCommand()
    Dim myTrans As MySqlTransaction
    
    ' Start a local transaction
    myTrans = myConnection.BeginTransaction()
    ' Must assign both transaction object and connection
    ' to Command object for a pending local transaction
    myCommand.Connection = myConnection
    myCommand.Transaction = myTrans
    
    Try
      myCommand.CommandText = "Insert into Region (RegionID, RegionDescription) VALUES (100, 'Description')"
      myCommand.ExecuteNonQuery()
      myCommand.CommandText = "Insert into Region (RegionID, RegionDescription) VALUES (101, 'Description')"
      myCommand.ExecuteNonQuery()
      myTrans.Commit()
      Console.WriteLine("Both records are written to database.")
    Catch e As Exception
      Try
        myTrans.Rollback()
      Catch ex As MySqlException
        If Not myTrans.Connection Is Nothing Then
          Console.WriteLine("An exception of type " & ex.GetType().ToString() & _
                            " was encountered while attempting to roll back the transaction.")
        End If
      End Try
    
      Console.WriteLine("An exception of type " & e.GetType().ToString() & _
                      "was encountered while inserting the data.")
      Console.WriteLine("Neither record was written to database.")
    Finally
      myConnection.Close()
    End Try
End Sub 'RunTransaction       
      

public void RunTransaction(string myConnString) 
 {
    MySqlConnection myConnection = new MySqlConnection(myConnString);
    myConnection.Open();

    MySqlCommand myCommand = myConnection.CreateCommand();
    MySqlTransaction myTrans;

    // Start a local transaction
    myTrans = myConnection.BeginTransaction();
    // Must assign both transaction object and connection
    // to Command object for a pending local transaction
    myCommand.Connection = myConnection;
    myCommand.Transaction = myTrans;

    try
    {
      myCommand.CommandText = "Insert into Region (RegionID, RegionDescription) VALUES (100, 'Description')";
      myCommand.ExecuteNonQuery();
      myCommand.CommandText = "Insert into Region (RegionID, RegionDescription) VALUES (101, 'Description')";
      myCommand.ExecuteNonQuery();
      myTrans.Commit();
      Console.WriteLine("Both records are written to database.");
    }
    catch(Exception e)
    {
      try
      {
        myTrans.Rollback();
      }
      catch (MySqlException ex)
      {
        if (myTrans.Connection != null)
        {
          Console.WriteLine("An exception of type " + ex.GetType() +
                            " was encountered while attempting to roll back the transaction.");
        }
      }
    
      Console.WriteLine("An exception of type " + e.GetType() +
                        " was encountered while inserting the data.");
      Console.WriteLine("Neither record was written to database.");
    }
    finally 
    {
      myConnection.Close();
    }
}       
      

All interaction between a .NET application and the MySQL server is routed through a MySqlConnection object. Before your application can interact with the server, a MySqlConnection object must be instanced, configured, and opened.

Even when using the MySqlHelper class, a MySqlConnection object is created by the helper class.

In this section, we will describe how to connect to MySQL using the MySqlConnection object.

The MySqlConnection object is configured using a connection string. A connection string contains sever key/value pairs, separated by semicolons. Each key/value pair is joined with an equals sign.

The following is a sample connection string:

    Server=127.0.0.1;Uid=root;Pwd=12345;Database=test;
    

In this example, the MySqlConnection object is configured to connect to a MySQL server at 127.0.0.1, with a username of root and a password of 12345. The default database for all statements will be the test database.

The following options are typically used (a full list of options is available in the API documentation):

Once you have created a connection string it can be used to open a connection to the MySQL server.

The following code is used to create a MySqlConnection object, assign the connection string, and open the connection.

[VB]

Dim conn As New MySql.Data.MySqlClient.MySqlConnection
Dim myConnectionString as String

myConnectionString = "server=127.0.0.1;" _
            & "uid=root;" _
            & "pwd=12345;" _
            & "database=test;"

Try
  conn.ConnectionString = myConnectionString
  conn.Open()

Catch ex As MySql.Data.MySqlClient.MySqlException
  MessageBox.Show(ex.Message)
End Try
  

[C#]

MySql.Data.MySqlClient.MySqlConnection conn;
string myConnectionString;
    
myConnectionString = "server=127.0.0.1;uid=root;" +
    "pwd=12345;database=test;";
  
try
{
    conn = new MySql.Data.MySqlClient.MySqlConnection();
    conn.ConnectionString = myConnectionString;
    conn.Open();
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
    MessageBox.Show(ex.Message);
}

You can also pass the connection string to the constructor of the MySqlConnection class:

[VB]

Dim myConnectionString as String

myConnectionString = "server=127.0.0.1;" _
              & "uid=root;" _
              & "pwd=12345;" _
              & "database=test;" 

Try
    Dim conn As New MySql.Data.MySqlClient.MySqlConnection(myConnectionString)
    conn.Open()
Catch ex As MySql.Data.MySqlClient.MySqlException
   MessageBox.Show(ex.Message)
End Try
  

[C#]

MySql.Data.MySqlClient.MySqlConnection conn;
string myConnectionString;

myConnectionString = "server=127.0.0.1;uid=root;" +
    "pwd=12345;database=test;";

try
{
    conn = new MySql.Data.MySqlClient.MySqlConnection(myConnectionString);
    conn.Open();
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
    MessageBox.Show(ex.Message);
}

Once the connection is open it can be used by the other MySQL Connector/NET classes to communicate with the MySQL server.

Because connecting to an external server is unpredictable, it is important to add error handling to your .NET application. When there is an error connecting, the MySqlConnection class will return a MySqlException object. This object has two properties that are of interest when handling errors:

When handling errors, you can your application's response based on the error number. The two most common error numbers when connecting are as follows:

The following code shows how to adapt the application's response based on the actual error:

[VB]

Dim myConnectionString as String

myConnectionString = "server=127.0.0.1;" _
          & "uid=root;" _
          & "pwd=12345;" _
          & "database=test;" 

Try
    Dim conn As New MySql.Data.MySqlClient.MySqlConnection(myConnectionString)
    conn.Open()
Catch ex As MySql.Data.MySqlClient.MySqlException
    Select Case ex.Number
        Case 0
            MessageBox.Show("Cannot connect to server. Contact administrator")
        Case 1045
            MessageBox.Show("Invalid username/password, please try again")
    End Select
End Try
  

[C#]

MySql.Data.MySqlClient.MySqlConnection conn;
string myConnectionString;

myConnectionString = "server=127.0.0.1;uid=root;" +  
    "pwd=12345;database=test;";

try
{
    conn = new MySql.Data.MySqlClient.MySqlConnection(myConnectionString);
    conn.Open();
}
    catch (MySql.Data.MySqlClient.MySqlException ex)
{
    switch (ex.Number)
    {
        case 0:
            MessageBox.Show("Cannot connect to server.  Contact administrator");
        case 1045:
            MessageBox.Show("Invalid username/password, please try again");
    }
}
  

Important Note that if you are using multilanguage databases you must specify the character set in the connection string. If you do not specify the character set, the connection defaults to the latin1 charset. You can specify the character set as part of the connection string, for example:

MySqlConnection myConnection = new MySqlConnection("server=127.0.0.1;uid=root;" +
    "pwd=12345;database=test;Charset=latin1;");

As of MySQL 4.1, it is possible to use prepared statements with MySQL Connector/NET. Use of prepared statements can provide significant performance improvements on queries that are executed more than once.

Prepared execution is faster than direct execution for statements executed more than once, primarily because the query is parsed only once. In the case of direct execution, the query is parsed every time it is executed. Prepared execution also can provide a reduction of network traffic because for each execution of the prepared statement, it is necessary only to send the data for the parameters.

Another advantage of prepared statements is that it uses a binary protocol that makes data transfer between client and server more efficient.

To prepare a statement, create a command object and set the .CommandText property to your query.

After entering your statement, call the .Prepare method of the MySqlCommand object. After the statement is prepared, add parameters for each of the dynamic elements in the query.

After you enter your query and enter parameters, execute the statement using the .ExecuteNonQuery(), .ExecuteScalar(), or .ExecuteReader methods.

For subsequent executions, you need only modify the values of the parameters and call the execute method again, there is no need to set the .CommandText property or redefine the parameters.

[VB]

Dim conn As New MySqlConnection
Dim cmd As New MySqlCommand
  
conn.ConnectionString = strConnection

Try
   conn.Open()
   cmd.Connection = conn
 
   cmd.CommandText = "INSERT INTO myTable VALUES(NULL, ?number, ?text)"
   cmd.Prepare()

   cmd.Parameters.Add("?number", 1)
   cmd.Parameters.Add("?text", "One")

   For i = 1 To 1000
       cmd.Parameters("?number").Value = i
       cmd.Parameters("?text").Value = "A string value"

       cmd.ExecuteNonQuery()
     Next 
Catch ex As MySqlException
    MessageBox.Show("Error " & ex.Number & " has occurred: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
  

[C#]

MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
  
conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();

conn.ConnectionString = strConnection;

try
{
    conn.Open();
    cmd.Connection = conn;

    cmd.CommandText = "INSERT INTO myTable VALUES(NULL, ?number, ?text)";
    cmd.Prepare();

    cmd.Parameters.Add("?number", 1);
    cmd.Parameters.Add("?text", "One");

    for (int i=1; i <= 1000; i++)
    {
        cmd.Parameters["?number"].Value = i;
        cmd.Parameters["?text"].Value = "A string value";

        cmd.ExecuteNonQuery();
    }
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
    MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message,
        "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}

With the release of MySQL version 5 the MySQL server now supports stored procedures with the SQL 2003 stored procedure syntax.

A stored procedure is a set of SQL statements that can be stored in the server. Once this has been done, clients don't need to keep reissuing the individual statements but can refer to the stored procedure instead.

Stored procedures can be particularly useful in situations such as the following:

MySQL Connector/NET supports the calling of stored procedures through the MySqlCommand object. Data can be passed in and our of a MySQL stored procedure through use of the MySqlCommand.Parameters collection.

This section will not provide in-depth information on creating Stored Procedures. For such information, please refer to http://dev.mysql.com/doc/mysql/en/stored-procedures.html.

A sample application demonstrating how to use stored procedures with MySQL Connector/NET can be found in the Samples directory of your MySQL Connector/NET installation.

Stored procedures in MySQL can be created using a variety of tools. First, stored procedures can be created using the mysql command-line client. Second, stored procedures can be created using the MySQL Query Browser GUI client. Finally, stored procedures can be created using the .ExecuteNonQuery method of the MySqlCommand object:

[VB]

Dim conn As New MySqlConnection
Dim cmd As New MySqlCommand

conn.ConnectionString = "server=127.0.0.1;" _
    & "uid=root;" _
    & "pwd=12345;" _
    & "database=test"

Try
    conn.Open()
    cmd.Connection = conn

    cmd.CommandText = "CREATE PROCEDURE add_emp(" _
        & "IN fname VARCHAR(20), IN lname VARCHAR(20), IN bday DATETIME, OUT empno INT) " _
        & "BEGIN INSERT INTO emp(first_name, last_name, birthdate) " _
        & "VALUES(fname, lname, DATE(bday)); SET empno = LAST_INSERT_ID(); END"
 
    cmd.ExecuteNonQuery()
Catch ex As MySqlException
    MessageBox.Show("Error " & ex.Number & " has occurred: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try

[C#]

MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;

conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();

conn.ConnectionString = "server=127.0.0.1;uid=root;" +
    "pwd=12345;database=test;";

try
{
    conn.Open();
    cmd.Connection = conn;

    cmd.CommandText = "CREATE PROCEDURE add_emp(" +
        "IN fname VARCHAR(20), IN lname VARCHAR(20), IN bday DATETIME, OUT empno INT) " +
        "BEGIN INSERT INTO emp(first_name, last_name, birthdate) " +
        "VALUES(fname, lname, DATE(bday)); SET empno = LAST_INSERT_ID(); END";

    cmd.ExecuteNonQuery();
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message,
    "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}

It should be noted that, unlike the command-line and GUI clients, you are not required to specify a special delimiter when creating stored procedures in MySQL Connector/NET.

To call a stored procedure using MySQL Connector/NET, create a MySqlCommand object and pass the stored procedure name as the .CommandText property. Set the .CommandType property to CommandType.StoredProcedure.

After the stored procedure is named, create one MySqlCommand parameter for every parameter in the stored procedure. IN parameters are defined with the parameter name and the object containing the value, OUT parameters are defined with the parameter name and the datatype that is expected to be returned. All parameters need the parameter direction defined.

After defining parameters, call the stored procedure by using the MySqlCommand.ExecuteNonQuery() method:

[VB]

Dim conn As New MySqlConnection
Dim cmd As New MySqlCommand

conn.ConnectionString = "server=127.0.0.1;" _
    & "uid=root;" _
    & "pwd=12345;" _
    & "database=test"

Try
    conn.Open()
    cmd.Connection = conn

    cmd.CommandText = "add_emp"
    cmd.CommandType = CommandType.StoredProcedure

    cmd.Parameters.Add("?lname", 'Jones')
    cmd.Parameters("?lname").Direction = ParameterDirection.Input

    cmd.Parameters.Add("?fname", 'Tom')
    cmd.Parameters("?fname").Direction = ParameterDirection.Input

    cmd.Parameters.Add("?bday", #12/13/1977 2:17:36 PM#)
    cmd.Parameters("?bday").Direction = ParameterDirection.Input

    cmd.Parameters.Add("?empno", MySqlDbType.Int32)
    cmd.Parameters("?empno").Direction = ParameterDirection.Output

    cmd.ExecuteNonQuery()

    MessageBox.Show(cmd.Parameters("?empno").Value)
Catch ex As MySqlException
    MessageBox.Show("Error " & ex.Number & " has occurred: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try

[C#]

MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;

conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();

conn.ConnectionString = "server=127.0.0.1;uid=root;" +
    "pwd=12345;database=test;";

try
{
    conn.Open();
    cmd.Connection = conn;

    cmd.CommandText = "add_emp";
    cmd.CommandType = CommandType.StoredProcedure;

    cmd.Parameters.Add("?lname", "Jones");
    cmd.Parameters["?lname"].Direction = ParameterDirection.Input;

    cmd.Parameters.Add("?fname", "Tom");
    cmd.Parameters["?fname"].Direction = ParameterDirection.Input;

    cmd.Parameters.Add("?bday", DateTime.Parse("12/13/1977 2:17:36 PM"));
    cmd.Parameters["?bday"].Direction = ParameterDirection.Input;

    cmd.Parameters.Add("?empno", MySqlDbType.Int32);
    cmd.Parameters["?empno"].Direction = ParameterDirection.Output;

    cmd.ExecuteNonQuery();

    MessageBox.Show(cmd.Parameters["?empno"].Value);
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
    MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message,
      "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}

Once the stored procedure is called, the values of output parameters can be retrieved by using the .Value property of the MySqlConnector.Parameters collection.

One common use for MySQL is the storage of binary data in BLOB columns. MySQL supports four different BLOB datatypes: TINYBLOB, BLOB, MEDIUMBLOB, and LONGBLOB.

Data stored in a BLOB column can be accessed using Connector/NET and manipulated using client-side code. There are no special requirements for using Connector/NET with BLOB data.

Simple code examples will be presented within this section, and a full sample application can be found in the Samples directory of the MySQL Connector/NET installation.

The first step is using MySQL with BLOB data is to configure the server. Let's start by creating a table to be accessed. In my file tables, I usually have four columns: an AUTO_INCREMENT column of appropriate size (UNSIGNED SMALLINT) to serve as a primary key to identify the file, a VARCHAR column that stores the filename, an UNSIGNED MEDIUMINT column that stores the size of the file, and a MEDIUMBLOB column that stores the file itself. For this example, I will use the following table definition:

CREATE TABLE file(
file_id SMALLINT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY,
file_name VARCHAR(64) NOT NULL,
file_size MEDIUMINT UNSIGNED NOT NULL,
file MEDIUMBLOB NOT NULL);

After creating a table, you may need to modify the max_allowed_packet system variable. This variable determines how large of a packet (i.e. a single row) can be sent to the MySQL server. By default, the server will only accept a maximum size of 1 meg from our client application. If you do not intend to exceed 1 meg, this should be fine. If you do intend to exceed 1 meg in your file transfers, this number has to be increased.

The max_allowed_packet option can be modified using MySQL Administrator's Startup Variables screen. Adjust the Maximum allowed option in the Memory section of the Networking tab to an appropriate setting. After adjusting the value, click the Apply Changes button and restart the server using the Service Control screen of MySQL Administrator. You can also adjust this value directly in the my.cnf file (add a line that reads max_allowed_packet=xxM), or use the SET max_allowed_packet=xxM; syntax from within MySQL.

Try to be conservative when setting max_allowed_packet, as transfers of BLOB data can take some time to complete. Try to set a value that will be adequate for your intended use and increase the value if necessary.

To write a file to a database we need to convert the file to a byte array, then use the byte array as a parameter to an INSERT query.

The following code opens a file using a FileStream object, reads it into a byte array, and inserts it into the file table:

[VB]

Dim conn As New MySqlConnection
Dim cmd As New MySqlCommand

Dim SQL As String

Dim FileSize As UInt32
Dim rawData() As Byte
Dim fs As FileStream

conn.ConnectionString = "server=127.0.0.1;" _
    & "uid=root;" _
    & "pwd=12345;" _
    & "database=test"

Try
    fs = New FileStream("c:\image.png", FileMode.Open, FileAccess.Read)
    FileSize = fs.Length
    
    rawData = New Byte(FileSize) {}
    fs.Read(rawData, 0, FileSize)
    fs.Close()
    
    conn.Open()
    
    SQL = "INSERT INTO file VALUES(NULL, ?FileName, ?FileSize, ?File)"
    
    cmd.Connection = conn
    cmd.CommandText = SQL
    cmd.Parameters.Add("?FileName", strFileName)
    cmd.Parameters.Add("?FileSize", FileSize)
    cmd.Parameters.Add("?File", rawData)
    
    cmd.ExecuteNonQuery()
    
    MessageBox.Show("File Inserted into database successfully!", _
    "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
    
    conn.Close()
Catch ex As Exception
    MessageBox.Show("There was an error: " & ex.Message, "Error", _
        MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
  

[C#]

MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;

conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();

string SQL;
UInt32 FileSize;
byte[] rawData;
FileStream fs;

conn.ConnectionString = "server=127.0.0.1;uid=root;" +
    "pwd=12345;database=test;";

try
{
    fs = new FileStream(@"c:\image.png", FileMode.Open, FileAccess.Read);
    FileSize = fs.Length;

    rawData = new byte[FileSize];
    fs.Read(rawData, 0, FileSize);
    fs.Close();

    conn.Open();

    SQL = "INSERT INTO file VALUES(NULL, ?FileName, ?FileSize, ?File)";

    cmd.Connection = conn;
    cmd.CommandText = SQL;
    cmd.Parameters.Add("?FileName", strFileName);
    cmd.Parameters.Add("?FileSize", FileSize);
    cmd.Parameters.Add("?File", rawData);

    cmd.ExecuteNonQuery();

    MessageBox.Show("File Inserted into database successfully!",
        "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);

    conn.Close();
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
    MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message,
        "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
 

The Read method of the FileStream object is used to load the file into a byte array which is sized according to the Length property of the FileStream object.

After assigning the byte array as a parameter of the MySqlCommand object, the ExecuteNonQuery method is called and the BLOB is inserted into the file table.

Once a file is loaded into the file table, we can use the MySqlDataReader class to retrieve it.

The following code retrieves a row from the file table, then loads the data into a FileStream object to be written to disk:

[VB]

Dim conn As New MySqlConnection
Dim cmd As New MySqlCommand
Dim myData As MySqlDataReader
Dim SQL As String
Dim rawData() As Byte
Dim FileSize As UInt32
Dim fs As FileStream

conn.ConnectionString = "server=127.0.0.1;" _
    & "uid=root;" _
    & "pwd=12345;" _
    & "database=test"

SQL = "SELECT file_name, file_size, file FROM file"

Try
    conn.Open()
    
    cmd.Connection = conn
    cmd.CommandText = SQL
    
    myData = cmd.ExecuteReader
    
    If Not myData.HasRows Then Throw New Exception("There are no BLOBs to save")
    
    myData.Read()
    
    FileSize = myData.GetUInt32(myData.GetOrdinal("file_size"))
    rawData = New Byte(FileSize) {}
    
    myData.GetBytes(myData.GetOrdinal("file"), 0, rawData, 0, FileSize)
    
    fs = New FileStream("C:\newfile.png", FileMode.OpenOrCreate, FileAccess.Write)
    fs.Write(rawData, 0, FileSize)
    fs.Close()
    
    MessageBox.Show("File successfully written to disk!", "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
    
    myData.Close()
    conn.Close()
Catch ex As Exception
    MessageBox.Show("There was an error: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
  

[C#]

MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
MySql.Data.MySqlClient.MySqlDataReader myData;

conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();

string SQL;
UInt32 FileSize;
byte[] rawData;
FileStream fs;

conn.ConnectionString = "server=127.0.0.1;uid=root;" +
    "pwd=12345;database=test;";

SQL = "SELECT file_name, file_size, file FROM file";

try
{
    conn.Open();

    cmd.Connection = conn;
    cmd.CommandText = SQL;

    myData = cmd.ExecuteReader();

    if (! myData.HasRows)
        throw new Exception("There are no BLOBs to save");

    myData.Read();

    FileSize = myData.GetUInt32(myData.GetOrdinal("file_size"));
    rawData = new byte[FileSize];

    myData.GetBytes(myData.GetOrdinal("file"), 0, rawData, 0, FileSize);

    fs = new FileStream(@"C:\newfile.png", FileMode.OpenOrCreate, FileAccess.Write);
    fs.Write(rawData, 0, FileSize);
    fs.Close();

    MessageBox.Show("File successfully written to disk!",
        "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);

    myData.Close();
    conn.Close();
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
    MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message,
        "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
 

After connecting, the contents of the file table are loaded into a MySqlDataReader object. The GetBytes method of the MySqlDataReader is used to load the BLOB into a byte array, which is then written to disk using a FileStream object.

The GetOrdinal method of the MySqlDataReader can be used to determine the integer index of a named column. Use of the GetOrdinal method prevents errors if the column order of the SELECT query is changed.

Crystal Reports is a common tool used by Windows application developers to perform reporting and document generation. In this section we will show how to use Crystal Reports XI with MySQL and Connector/NET.

Complete sample applications are available in the CrystalDemo subdirectory of the Samples directory of your MySQL Connector/NET installation.

When creating a report in Crystal Reports there are two options for accessing the MySQL data while designing your report.

The first option is to use Connector/ODBC as an ADO data source when designing your report. You will be able to browse your database and choose tables and fields using drag and drop to build your report. The disadvantage of this approach is that additional work must be performed within your application to produce a dataset that matches the one expected by your report.

The second option is to create a dataset in VB.NET and save it as XML. This XML file can then be used to design a report. This works quite well when displaying the report in your application, but is less versatile at design time because you must choose all relevant columns when creating the dataset. If you forget a column you must re-create the dataset before the column can be added to the report.

The following code can be used to create a dataset from a query and write it to disk:

[VB]

Dim myData As New DataSet
Dim conn As New MySqlConnection
Dim cmd As New MySqlCommand
Dim myAdapter As New MySqlDataAdapter

conn.ConnectionString = "server=127.0.0.1;" _
    & "uid=root;" _
    & "pwd=12345;" _
    & "database=world"

Try
    conn.Open()
    cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " _ 
        & "country.name, country.population, country.continent " _
        & "FROM country, city ORDER BY country.continent, country.name"
    cmd.Connection = conn
    
    myAdapter.SelectCommand = cmd
    myAdapter.Fill(myData)
    
    myData.WriteXml("C:\dataset.xml", XmlWriteMode.WriteSchema)
Catch ex As Exception
    MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
 

[C#]

DataSet myData = new DataSet();
MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
MySql.Data.MySqlClient.MySqlDataAdapter myAdapter;

conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();
myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter();

conn.ConnectionString = "server=127.0.0.1;uid=root;" +
  "pwd=12345;database=test;";
  
try
{
  cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " +
  "country.name, country.population, country.continent " +
  "FROM country, city ORDER BY country.continent, country.name";
  cmd.Connection = conn;
  
  myAdapter.SelectCommand = cmd;
  myAdapter.Fill(myData);
  
  myData.WriteXml(@"C:\dataset.xml", XmlWriteMode.WriteSchema);
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
  MessageBox.Show(ex.Message, "Report could not be created",
  MessageBoxButtons.OK, MessageBoxIcon.Error);
}

The resulting XML file can be used as an ADO.NET XML datasource when designing your report.

If you choose to design your reports using Connector/ODBC, it can be downloaded from dev.mysql.com.

For most purposes the Standard Report wizard should help with the initial creation of a report. To start the wizard, open Crystal Reports and choose the New > Standard Report option from the File menu.

The wizard will first prompt you for a data source. If you are using Connector/ODBC as your data source, use the OLEDB provider for ODBC option from the OLE DB (ADO) tree instead of the ODBC (RDO) tree when choosing a data source. If using a saved dataset, choose the ADO.NET (XML) option and browse to your saved dataset.

The remainder of the report creation process is done automatically by the wizard.

After the report is created, choose the Report Options... entry of the File menu. Un-check the Save Data With Report option. This prevents saved data from interfering with the loading of data within our application.

To display a report we first populate a dataset with the data needed for the report, then load the report and bind it to the dataset. Finally we pass the report to the crViewer control for display to the user.

The following references are needed in a project that displays a report:

The following code assumes that you created your report using a dataset saved using the code shown in Section 23.2.4.6.2, “Creating a Data Source”, and have a crViewer control on your form named myViewer.

[VB]

Imports CrystalDecisions.CrystalReports.Engine
Imports System.Data
Imports MySql.Data.MySqlClient

Dim myReport As New ReportDocument
Dim myData As New DataSet
Dim conn As New MySqlConnection
Dim cmd As New MySqlCommand
Dim myAdapter As New MySqlDataAdapter

conn.ConnectionString = _
    "server=127.0.0.1;" _
    & "uid=root;" _
    & "pwd=12345;" _
    & "database=test"

Try
    conn.Open()
    
    cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " _ 
        & "country.name, country.population, country.continent " _
        & "FROM country, city ORDER BY country.continent, country.name"
    cmd.Connection = conn
    
    myAdapter.SelectCommand = cmd
    myAdapter.Fill(myData)
    
    myReport.Load(".\world_report.rpt")
    myReport.SetDataSource(myData)
    myViewer.ReportSource = myReport
Catch ex As Exception
    MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try

[C#]

using CrystalDecisions.CrystalReports.Engine;
using System.Data;
using MySql.Data.MySqlClient;

ReportDocument myReport = new ReportDocument();
DataSet myData = new DataSet();
MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
MySql.Data.MySqlClient.MySqlDataAdapter myAdapter;

conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();
myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter();

conn.ConnectionString = "server=127.0.0.1;uid=root;" +
    "pwd=12345;database=test;";

try
{
    cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " +
        "country.name, country.population, country.continent " +
        "FROM country, city ORDER BY country.continent, country.name";
    cmd.Connection = conn;

    myAdapter.SelectCommand = cmd;
    myAdapter.Fill(myData);

    myReport.Load(@".\world_report.rpt");
    myReport.SetDataSource(myData);
    myViewer.ReportSource = myReport;
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
    MessageBox.Show(ex.Message, "Report could not be created",
        MessageBoxButtons.OK, MessageBoxIcon.Error);
}

A new dataset it generated using the same query used to generate the previously saved dataset. Once the dataset is filled, a ReportDocument is used to load the report file and bind it to the dataset. The ReportDocument is the passed as the ReportSource of the crViewer.

This same approach is taken when a report is created from a single table using Connector/ODBC. The dataset replaces the table used in the report and the report is displayed properly.

When a report is created from multiple tables using Connector/ODBC, a dataset with multiple tables must be created in our application. This allows each table in the report data source to be replaced with a report in the dataset.

We populate a dataset with multiple tables by providing multiple SELECT statements in our MySqlCommand object. These SELECT statements are based on the SQL query shown in Crystal Reports in the Database menu's Show SQL Query option. Assume the following query:

SELECT `country`.`Name`, `country`.`Continent`, `country`.`Population`, `city`.`Name`, `city`.`Population`
FROM `world`.`country` `country` LEFT OUTER JOIN `world`.`city` `city` ON `country`.`Code`=`city`.`CountryCode`
ORDER BY `country`.`Continent`, `country`.`Name`, `city`.`Name`

This query is converted to two SELECT queries and displayed with the following code:

[VB]

Imports CrystalDecisions.CrystalReports.Engine
Imports System.Data
Imports MySql.Data.MySqlClient

Dim myReport As New ReportDocument
Dim myData As New DataSet
Dim conn As New MySqlConnection
Dim cmd As New MySqlCommand
Dim myAdapter As New MySqlDataAdapter

conn.ConnectionString = "server=127.0.0.1;" _
    & "uid=root;" _
    & "pwd=12345;" _
    & "database=world"

Try
    conn.Open()
    cmd.CommandText = "SELECT name, population, countrycode FROM city ORDER BY countrycode, name; " _
        & "SELECT name, population, code, continent FROM country ORDER BY continent, name"
    cmd.Connection = conn
    
    myAdapter.SelectCommand = cmd
    myAdapter.Fill(myData)
    
    myReport.Load(".\world_report.rpt")
    myReport.Database.Tables(0).SetDataSource(myData.Tables(0))
    myReport.Database.Tables(1).SetDataSource(myData.Tables(1))
    myViewer.ReportSource = myReport
Catch ex As Exception
    MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try

[C#]

using CrystalDecisions.CrystalReports.Engine;
using System.Data;
using MySql.Data.MySqlClient;

ReportDocument myReport = new ReportDocument();
DataSet myData = new DataSet();
MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
MySql.Data.MySqlClient.MySqlDataAdapter myAdapter;

conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();
myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter();

conn.ConnectionString = "server=127.0.0.1;uid=root;" +
    "pwd=12345;database=test;";

try
{
    cmd.CommandText = "SELECT name, population, countrycode FROM city ORDER " +
        "BY countrycode, name; SELECT name, population, code, continent FROM " +
        "country ORDER BY continent, name";
    cmd.Connection = conn;

    myAdapter.SelectCommand = cmd;
    myAdapter.Fill(myData);

    myReport.Load(@".\world_report.rpt");
    myReport.Database.Tables(0).SetDataSource(myData.Tables(0));
    myReport.Database.Tables(1).SetDataSource(myData.Tables(1));
    myViewer.ReportSource = myReport;
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
    MessageBox.Show(ex.Message, "Report could not be created",
        MessageBoxButtons.OK, MessageBoxIcon.Error);
}  
 

It is important to order the SELECT queries in alphabetical order, as this is the order the report will expect its source tables to be in. One SetDataSource statement is needed for each table in the report.

This approach can cause performance problems because Crystal Reports must bind the tables together on the client-side, which will be slower than using a pre-saved dataset.

MySQL and the .NET languages handle date and time information differently, with MySQL allowing dates that cannot be represented by a .NET data type, such as '0000-00-00 00:00:00'. These differences can cause problems if not properly handled.

In this section we will demonstrate how to properly handle date and time information when using MySQL Connector/NET.

The differences in date handling can cause problems for developers who use invalid dates. Invalid MySQL dates cannot be loaded into native .NET DateTime objects, including NULL dates.

Because of this issue, .NET DataSet objects cannot be populated by the Fill method of the MySqlDataAdapter class as invalid dates will cause a System.ArgumentOutOfRangeException exception to occur.

The best solution to the date problem is to restrict users from entering invalid dates. This can be done on either the client or the server side.

Restricting invalid dates on the client side is as simple as always using the .NET DateTime class to handle dates. The DateTime class will only allow valid dates, ensuring that the values in your database are also valid. The disadvantage of this is that it is not useful in a mixed environment where .NET and non .NET code are used to manipulate the database, as each application must perform its own date validation.

Users of MySQL 5.0.2 and higher can use the new traditional SQL mode to restrict invalid date values. For information on using the traditional SQL mode, see Section 5.2.5, “The Server SQL Mode”.

Although it is strongly recommended that you avoid the use of invalid dates within your .NET application, it is possible to use invalid dates by means of the MySqlDateTime datatype.

The MySqlDateTime datatype supports the same date values that are supported by the MySQL server. The default behavior of MySQL Connector/NET is to return a .NET DateTime object for valid date values, and return an error for invalid dates. This default can be modified to cause MySQL Connector/NET to return MySqlDateTime objects for invalid dates.

To instruct MySQL Connector/NET to return a MySqlDateTime object for invalid dates, add the following line to your connection string:

  Allow Zero Datetime=True
  

Please note that the use of the MySqlDateTime class can still be problematic. The following are some known issues:

Because of the known issues, the best recommendation is still to use only valid dates in your application.

The .NET DateTime datatype cannot handle NULL values. As such, when assigning values from a query to a DateTime variable, you must first check whether the value is in fact NULL.

When using a MySqlDataReader, use the .IsDBNull method to check whether a value is NULL before making the assignment:

[VB]

If Not myReader.IsDBNull(myReader.GetOrdinal("mytime")) Then
    myTime = myReader.GetDateTime(myReader.GetOrdinal("mytime"))
Else
    myTime = DateTime.MinValue
End If
  

[C#]

if (! myReader.IsDBNull(myReader.GetOrdinal("mytime")))
    myTime = myReader.GetDateTime(myReader.GetOrdinal("mytime"));
else
    myTime = DateTime.MinValue;
  

NULL values will work in a dataset and can be bound to form controls without special handling.