Purpose
You can use the CREATE CONTEXT statement to create a namespace for a context (a group of application-defined attributes that are used to validate and protect the application) and associate the namespace with the package that is externally created to set this context.
You can use the DBMS_SESSION.SET_CONTEXT procedure in the specified package to set or reset the context attributes.
Notice
To create a context namespace, you must have the CREATE ANY CONTEXT system privilege.
Syntax
CREATE [ OR REPLACE ] CONTEXT namespace
USING [ schema. ] package_name
[ INITIALIZED { EXTERNALLY | GLOBALLY }
| ACCESSED GLOBALLY
] ;
Parameters
Parameter |
Description |
|---|---|
| OR REPLACE | Uses a different package to redefine the existing context namespace. |
| namespace | The name of the context namespace to be created or modified. Context namespaces are always stored in the schema SYS. |
| schema | The schema to which the package belongs. If you do not specify this parameter, the current schema is used. |
| package_name | The name of the PL package that is used to set or reset the context attributes in the namespace of the current session. |
| ACCESSED GLOBALLY | Specifies that any application context set in the namespace can be accessed in the entire instance. This setting allows multiple sessions to share application attributes. |
Examples
Create a context namespace named
dev_context.obclient> CREATE OR REPLACE CONTEXT dev_context USING SYS.DBMS_SESSION ACCESSED GLOBALLY; Query OK, 0 rows affectedUse the
SYS_CONTEXT()function to control data access based on this context. In the following example, theemp_mgmtpackage defines thedeptnoattribute as the identifier of the specified department. You can create a view based on thedeptnovalue to restrict access to employee data in the base table.obclient> CREATE VIEW dev_emp_view AS SELECT * FROM emp WHERE deptno = SYS_CONTEXT('dev_context', 'deptno'); Query OK, 0 rows affected