Data types mappings for relational data sources include forward
type mappings, reverse type mappings, and type mappings that are specific
to Unicode. Each of the nonrelational data sources support specific
data types.
Default forward data type mappings
The two kinds of mappings between data source data types and federated
database data types are forward type mappings and reverse type mappings. In
a forward type mapping, the mapping is
from a remote type to a comparable local type.
Unicode default data type mappings
Specific data sources support forward data type mappings and reverse
data type mappings for Unicode databases.
Data types supported for nonrelational data sources
For most of the nonrelational data sources, you must specify
the column information, including data type, when you create the nicknames
to access the data source.