9.4 Advanced JDBC Data Types

The ISO (International Organization for Standardization) and IEC (the International Electrotechnical Commission) have defined new data types that are commonly referred to as SQL99 types. Of these new SQL99 data types, BLOB, CLOB, ARRAY, and REF are predefined types, whereas the SQL structured type and the DISTINCT type are user-defined types (UDTs). These new types, with the exception of DISTINCT, are mapped to interfaces that were introduced in the JDBC 2.0 core API. This section describes each data type briefly; more complete information on each type can be found in the reference chapter for the corresponding interface. There is a chapter on the DISTINCT data type, but because DISTINCT types are mapped to a built-in type, there is no separate interface for it.
The new data types introduced in the JDBC 2.0 core API represent a significant expansion in the types of data that can be used in a relational database. In general, they are more like objects; in fact, two of the new data types are UDTs that can optionally be custom mapped to classes