Result Set and Statement Extensions

The JDBC Statement object returns an OracleResultSet object, typed as a java.sql.ResultSet. If you want to apply only standard JDBC methods to the object, keep it as a ResultSet type. However, if you want to use the Oracle extensions on the object, you must cast it to an OracleResultSet type. Although the type by which the Java compiler will identify the object is changed, the object itself is unchanged.

For example, assuming you have a standard Statement object stmt, do the following if you want to use only standard JDBC ResultSet methods:

ResultSet rs = stmt.executeQuery("SELECT * FROM emp");

If you need the extended functionality provided by the Oracle extensions to JDBC, you can select the results into a standard ResultSet object, as above, and then cast that object into an OracleResultSet object later.

Similarly, when you want to execute a stored procedure using a callable statement, the JDBC drivers will return an OracleCallableStatement object typed as a java.sql.CallableStatement. If you want to apply only standard JDBC methods to the object, then keep it as a CallableStatement type. However, if you want to use the Oracle extensions on the object, you must cast it to an OracleCallableStatement type. Although the type by which the Java compiler will identify the object is changed, the object itself is unchanged.

You use the standard JDBC java.sql.Connection.prepareStatement() method to create a PreparedStatement object. If you want to apply only standard JDBC methods to the object, keep it as a PreparedStatement type. However, if you want to use the Oracle extensions on the object, you must cast it to an OraclePreparedStatement type. While the type by which the Java compiler will identify the object is changed, the object itself is unchanged.

Key extensions to the result set and statement classes include getOracleObject() and setOracleObject() methods that you can use to access and manipulate data in oracle.sql.* formats, instead of standard Java formats. For more information, see the next section: "Comparison of Oracle get and set Methods to Standard JDBC".

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