Data type mappings

The data types at the data source must map to corresponding Db2® data types so that the federated server can retrieve data from data sources.

Some examples of default data type mappings are:
  • The Oracle type FLOAT maps to the data type DOUBLE
  • The Oracle type DATE maps to the data type TIMESTAMP
  • The Db2 for z/OS® type DATE maps to the data type DATE

For most data sources, the default type mappings are in the wrappers. The default type mappings for Db2 data sources are in the DRDA wrapper. The default type mappings for Informix® are in the INFORMIX wrapper, and so forth.

For some non-relational data sources, you must specify data type information in the CREATE NICKNAME statement. The corresponding data types must be specified for each column of the data source object when the nickname is created. Each column must be mapped to a particular field or column in the data source object.

For relational data sources, you can override the default data type mappings. For example, by default the Informix INTEGER data type maps to the INTEGER data type. You could override the default mappings and map the Informix INTEGER data type to DECIMAL(10,0) data type.