Sets or gets a value which indicates whether the source column is nullable. This allows OracleCommandBuilder to correctly generate Update statements for nullable columns.
Assembly: System.Data.OracleClient (in System.Data.OracleClient.dll)
'Declaration Public Overrides Property SourceColumnNullMapping As Boolean 'Usage Dim instance As OracleParameter Dim value As Boolean value = instance.SourceColumnNullMapping instance.SourceColumnNullMapping = value
Property ValueType: System.Boolean
True if the source column is nullable, otherwise false.
DbCommandBuilder uses this property to determine whether the source column is nullable, and sets this property to true if it is nullable, and false if it is not. When OracleCommandBuilder is generating its Update statement, it examines the for each parameter. If the property is true, OracleCommandBuilder generates a WHERE clauses like the following (in this query expression, "FieldName" represents the name of the field):
((@IsNull_FieldName = 1 AND FieldName IS NULL) OR (FieldName = @Original_FieldName))
If for the field is false, OracleCommandBuilder generates the following WHERE clause:
FieldName = @OriginalFieldName
In addition, @IsNull_FieldName contains 1 if the source field contains null, and 0 if it does not. This mechanism allows for a performance optimization in Oracle Server, and provides for common code that works across multiple providers.
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
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