Mapping is setting up a correspondence between a PL/SQL datatype and a Java datatype.
When you build a PL/SQL call spec, the PL/SQL and Java parameters, as well as the function result, are related by position and must have compatible datatypes. The following table lists all the datatype mappings currently allowed between PL/SQL and Java. If you rely on a supported datatype mapping, Oracle will convert from one to the other automatically.
Oracle supports only automatic conversion for SQL datatypes. PL/SQL-specific datatypes, including BINARY_INTEGER, PLS_INTEGER, BOOLEAN, and index-by table types, are not supported. In those cases, you will have to perform manual conversion steps to transfer data between these two execution environments.