Overview of DBMS_LOB

The DBMS_LOB package provides most LOB operations, such as reading and modifying BLOB and CLOB values.

Privilege requirements for DBMS_LOB

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

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

When creating a subprogram, you can set the AUTHID parameter to specify whether the subprogram uses 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 complete a DBMS_LOB subprogram operation, 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.