When you create a mapping, you create a set of instructions for the Integration Service to read data from the source table, transform it, and write it to a target table. The Integration Service transforms data based on dataflow in the mapping, starting at the first transformation in the mapping, and the datatype assigned to each port in a mapping.
The Designer displays two types of datatypes:
Specific to the source and target databases, flat files, or ERP systems. Native datatypes appear in the Source Analyzer and Target Designer. They also appear in source and target definitions in the Mapping Designer and in source definitions in the Mapplet Designer.
Set of datatypes that appear in the transformations. They are internal datatypes based on ANSI SQL-92 generic datatypes, which the Integration Service uses to move data across platforms. Because the transformation datatypes are generic, you can use different source and target platforms. For example, you can read information from an Oracle source and write it to a Sybase target. Likewise, you can read information from a flat file and write it to a Microsoft SQL Server database. The transformation datatypes appear in all transformations in a mapping.
When the Integration Service reads source data, it converts the native datatypes to the comparable transformation datatypes before transforming the data. When the Integration Service writes to a target, it converts the transformation datatypes to the comparable native datatypes.
When you specify a multibyte character set, the datatypes allocate additional space in the database to store characters of up to three bytes.