Mapping Data Types in the Data Flow
New: 5 December 2005
While moving data from sources through transformations to destinations, a data flow component must sometimes convert data types between the SQL Server 2005 Integration Services (SSIS) types defined in the DataType enumeration and the managed data types of the Microsoft .NET Framework defined in the System namespace. In addition, a component must sometimes convert one Integration Services data type to another before that type can be converted to a managed type.
Note
The mapping files in XML format that are installed by default to C:\Program Files\Microsoft SQL Server\90\DTS\MappingFiles are not related to the data type mapping discussed in this topic. These files map data types from one database version or system to another (for example, from SQL Server 2000 to SQL Server 2005, or from SQL Server 2005 to Oracle), and are used only by the SQL Server Import and Export Wizard. For more information on these mapping files, see Creating Packages Using the SQL Server Import and Export Wizard.
Mapping between Integration Services and Managed Data Types
Sometimes a data flow component must convert data types between the SQL Server 2005 Integration Services (SSIS) types defined in the DataType enumeration and the managed data types of the Microsoft .NET Framework defined in the System namespace. The following table lists the conversions that are currently performed by the BufferTypeToDataRecordType and the DataRecordTypeToBufferType methods of the PipelineComponent class.
Warning
Developers should use these methods of the PipelineComponent class with caution, and may want to code data type mapping methods of their own that are more suited to the unique needs of their custom components. The existing methods do not consider numeric precision or scale, or other properties closely related to the data type itself. Microsoft may modify or remove these methods, or modify the mappings that they perform, in a future version of Integration Services.
| Integration Services Data Type | Managed Data Type |
|---|---|
System.String |
|
Array of System.Byte |
|
System.DateTime |
|
System.Decimal |
|
System.Guid |
|
System.Byte |
|
System.Int16 |
|
System.Int32 |
|
System.Int64 |
|
System.Boolean |
|
System.Single |
|
System.Double |
|
System.Byte |
|
System.UInt16 |
|
System.UInt32 |
|
System.UInt64 |
Converting Integration Services Data Types to Fit Managed Data Types
Sometimes a data flow component must also convert one Integration Services data type to another before that type can be converted to a managed type. The following table lists the conversions that are currently performed by the ConvertBufferDataTypeToFitManaged method of the PipelineComponent class.
Warning
Developers should use these methods of the PipelineComponent class with caution, and may want to code data type mapping methods of their own that are more suited to the unique needs of their custom components. The existing methods do not consider numeric precision or scale, or other properties closely related to the data type itself. Microsoft may modify or remove these methods, or modify the mappings that they perform, in a future version of Integration Services.
| Original Data Type | Converted Data Type |
|---|---|
DT_NUMERIC |
|
DT_DBTIMESTAMP |
|
DT_BOOL |
DT_I4 |
DT_WSTR |
|
DT_WSTR |
|
DT_BYTES |
See Also
Reference
BufferTypeToDataRecordType
DataRecordTypeToBufferType
ConvertBufferDataTypeToFitManaged
Other Resources
Integration Services Data Types