CallableStatement

CallableStatement is a sub-interface of the JDBC API's PreparedStatement that enables calling stored procedures and functions in a relational database. It supports input, output, and input/output parameters and may produce one or more result sets.

A CallableStatement is created from a Connection by using prepareCall with a call string that uses JDBC escape syntax, for example { call procedure_name(?, ?) } or { ? = call function_name(?) }. Input parameters are supplied with the standard setX methods inherited from PreparedStatement. Output or INOUT parameters are declared with registerOutParameter, specifying the parameter index and SQL type (and optionally a type name for user-defined types).

After setting inputs and registering outputs, the statement is executed via execute, executeQuery, or executeUpdate. Output values are retrieved after execution using the appropriate getter methods (for example getInt, getString, getObject) by parameter index. If the call returns a ResultSet, it can be processed as usual; the ResultSet may be retrieved via getResultSet or obtained in the usual manner depending on the driver.

Notes: Parameters are indexed starting at 1. Parameter metadata can be obtained with getParameterMetaData. Not all drivers support every feature, and some may provide extended behavior such as named parameters or additional metadata. Always close the CallableStatement to release resources, ideally using try-with-resources or a finally block. When used within a transaction, ensure proper commit or rollback handling.