12_les_11_App_Context数据库安全审计.ppt

Using Application Contexts Objectives After completing this lesson, you should be able to do the following: Describe how an application context is used Describe the sources of application context values Implement a local context Implement an application context that is accessed globally Application Context: Description An application context is a memory container with attributes: The container is called a namespace. A namespace has attributes. Each namespace is independent of others. The namespace is populated by a package. Namespace Using the Application Context An application context: Is read by applications Can be used to: Authorize users Limit access to data, called by a FGAC policy Set attributes used in the application Setting the Application Context The context attributes are set by a package, which: Creates attributes in the context Assigns values to the attributes of the context Is usually called when a user connects Each application can use one or more contexts. A context may be used by multiple applications. USERENV is a built-in context with session properties and is available to all applications. Application Context Data Sources The built-in USERENV context contains session primitives as attributes. Example: Client IP address A local context uses database objects. The developer sets these attributes. Example: The EMPLOYEE_ID column in the EMPLOYEES table An externalized context can get values from an external source, such as Oracle Call Interface (OCI). A global context uses values from the directory-entry attributes. Implementing a Local Context Create an application context. Create a PL/SQL package that sets the context. Call the package to set the context attribute. Read the context attribute in the application. Step 1: Create an Application Context Create a unique context: Names the context HRAPP Associates it with an HR_CONTEXT package You can set the context attributes only in the: Package named in CREATE CONTEXT Function associated with a polic