Overview of DBMS_LOB

The DBMS_LOB package provides most LOB operations for reading and modifying BLOB and CLOB values.

Privilege requirements for DBMS_LOB

The DBMS_LOB package must be created in the SYS schema. However, the operations provided by this package are executed under the privileges of the current user, not in the SYS schema.

Any DBMS_LOB subprogram called from an anonymous PL block is executed under the privileges of the current user. Any DBMS_LOB subprogram called from a stored subprogram is executed under the privileges of the owner of the stored subprogram.

When creating a subprogram, you can set the AUTHID parameter to specify whether the subprogram should use the privileges of the definer or the invoker. Here are two examples:

CREATE PROCEDURE proc1 AUTHID DEFINER ...

or

CREATE PROCEDURE proc1 AUTHID CURRENT_USER ...

Data types used by DBMS_LOB

Considerations for using DBMS_LOB

All DBMS_LOB subprograms operate based on LOB locators. To successfully execute DBMS_LOB subprogram operations, you must provide an input locator that represents an existing LOB in the database tablespace or external file system.

All DBMS_LOB APIs now support operations on remote LOB locators. Any API that uses two locators must have both LOB values in the same database.

Overview of DBMS_LOB subprograms

The following table lists the DBMS_LOB subprograms supported in the current version of OceanBase Database and their brief descriptions.