IDbCommand.Prepare Method ()


Creates a prepared (or compiled) version of the command on the data source.

Namespace:   System.Data
Assembly:  System.Data (in System.Data.dll)

Sub Prepare

Exception Condition

The Connection is not set.


The Connection is not Open.

If the CommandType property is set to TableDirect, Prepare does nothing. If CommandType is set to StoredProcedure, the call to Prepare should succeed, although it may result in a no-op. The server automatically caches plans for reuse as necessary; therefore, there is no need to call this method directly in your client application.

The following example creates an instance of the derived class, OleDbCommand, and opens the connection. The example then prepares a stored procedure on the data source by passing a string that is a SQL Select statement and a string to use to connect to the data source.

Public Sub OleDbCommandPrepare(ByVal connectionString As String)

    Using connection As OleDbConnection = New _

        ' Create the Command.
        Dim command As OleDbCommand = New OleDbCommand()

        ' Set the Connection, CommandText and Parameters.
        command.Connection = connection
        command.CommandText = _
          "INSERT INTO dbo.Region (RegionID, RegionDescription) VALUES (?, ?);"
        command.Parameters.Add("RegionID", OleDbType.Integer, 4)
        command.Parameters.Add("RegionDescription", OleDbType.VarWChar, 50)
        command.Parameters(0).Value = 20
        command.Parameters(1).Value = "First Region"

        ' Call  Prepare and ExecuteNonQuery.

        ' Change parameter values and call ExecuteNonQuery.
        command.Parameters(0).Value = 21
        command.Parameters(1).Value = "Second Region"
    End Using
End Sub

.NET Framework
Available since 1.1
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