Parameters

Each parameter has a data type.The NOT NULL constraint can also be specified for any parameter, to prevent NULL being passed or assigned to it.

A collation can be specified for string-type parameters, using the COLLATE clause.

Input Parameters: Input parameters are presented as a parenthesized list following the name of the function.They are passed by value into the procedure, so any changes inside the procedure has no effect on the parameters in the caller.Input parameters may have default values.Parameters with default values specified must be added at the end of the list of parameters.
Output Parameters: The optional RETURNS clause is for specifying a parenthesised list of output parameters for the stored procedure.

SQL Security

The SQL SECURITY clause specifies the security context for executing other routines or inserting into other tables.When SQL Security is not specified, the default value of the database is applied at runtime.

The SQL SECURITY clause can only be specified for PSQL procedures, and is not valid for procedures defined in a package.

See also SQL Security in chapter Security.