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Working with Data Types in the Data Flow

When developing a custom data flow component in Integration Services, you work constantly with data types, copying data into and out of data flow buffers and transforming values. The information in this topic helps you to choose the correct Integration Services data types, and to use the correct methods when working with them.

The PipelineBuffer class provides a series of Set methods for copying data into buffer columns, and a corresponding series of Get methods for retrieving data from buffer columns. The following tables show you which method to use with each Integration Services data type.

Set Methods to use with Data Types

Data Types to Use with the Set Methods

While moving data from sources through transformations to destinations, a data flow component must sometimes convert data types between the SQL Server Integration Services 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 Note

The mapping files in XML format that are installed by default to C:\Program Files\Microsoft SQL Server\110\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 to Oracle), and are used only by the SQL Server Import and Export Wizard. For more information on these mapping files, see SQL Server Import and Export Wizard.

Mapping between Integration Services and Managed Data Types

The PipelineComponent.BufferTypeToDataRecordType and the PipelineComponent.DataRecordTypeToBufferType methods map Integration Services data types to managed data types.

Caution note Caution

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.

The following table lists how the BufferTypeToDataRecordType and the DataRecordTypeToBufferType methods map various Integration Services data types to managed data types.

Integration Services Data Type

Maps to this Managed Data Type

DT_WSTR

System.String

DT_BYTES

Array of System.Byte

DT_DBTIMESTAMP

System.DateTime

DT_DBTIMESTAMP2

System.DateTime

DT_DBTIMESTAMPOFFSET

System.DateTimeOffset

DT_DBDATE

System.DateTime

DT_DBTIME

System.TimeSpan

DT_DBTIME2

System.TimeSpan

DT_DATE

System.DateTime

DT_FILETIME

System.DateTime

DT_NUMERIC

System.Decimal

DT_GUID

System.Guid

DT_I1

System.SByte

DT_I2

System.Int16

DT_I4

System.Int32

DT_I8

System.Int64

DT_BOOL

System.Boolean

DT_R4

System.Single

DT_R8

System.Double

DT_UI1

System.Byte

DT_UI2

System.UInt16

DT_UI4

System.UInt32

DT_UI8

System.UInt64

Mapping 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 PipelineComponent.ConvertBufferDataTypeToFitManaged method class maps Integration Services data types to other Integration Services data types that can then be mapped to managed data types by using the PipelineComponent.BufferTypeToDataRecordType method.

Caution note Caution

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.

The following table lists how the ConvertBufferDataTypeToFitManaged method maps Integration Services data types to other Integration Services data types.

Note Note

The ConvertBufferDataTypeToFitManaged method does not return a value for the DT_DBTIMESTAMPOFFSET data type, and a UnsupportedBufferDataTypeException occurs. You must convert the DT_DBTIMESTAMPOFFSET data type to one of the Integration Services date/time data types that can be mapped to a managed data type. For a list of Integration Services date/time data types that can be mapped to a managed data types, see the table in the previous section, "Mapping between Integration Services and Managed Data Types." For information about converting data types, see Integration Services Data Types.

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