This chapter explains how to use the SQL statements that create, change, and drop stored PL/SQL units.
For instructions for reading the syntax diagrams in this chapter, see Oracle Database SQL Language Reference.
CREATE [OR REPLACE] Statements
Each of the following SQL statements creates a PL/SQL unit and stores it in the database:
Each of these CREATE statements has an optional OR REPLACE clause. Specify OR REPLACE to re-create an existing PL/SQL unit—that is, to change its declaration or definition without dropping it, re-creating it, and regranting object privileges previously granted on it. If you redefine a PL/SQL unit, the database recompiles it.
None of these CREATE statements can appear in a PL/SQL block.
If you want to recompile an existing PL/SQL unit without re-creating it (without changing its declaration or definition), use one of the following SQL statements:
Two reasons to use an ALTER statement are:
To explicitly recompile a stored unit that has become invalid, thus eliminating the need for implicit run-time recompilation and preventing associated run-time compilation errors and performance overhead.
To recompile a unit with different compilation parameters.
For information about compilation parameters, see PL/SQL Units and Compilation Parameters.
The ALTER TYPE statement has additional uses. For details, see ALTER TYPE Statement.
To drop an existing PL/SQL unit from the database, use one of the following SQL statements: