OCP-1Z0-053-V12.02-429题

429.Which of the following supplied functions is used to identify external tables, directories, and BFILES?

A. DBMS_TDB.CHECK_DIRECTORIES

B. DBMS_TDB.CHECK_EXTERNAL

C. DBMS_TDB.CHECK_BFILE

D. DBMS_TDB.CHECK_EXT

Answer: B

答案解析：

参考：http://docs.oracle.com/cd/E11882_01/appdev.112/e40758/d_tdb.htm#ARPLS68854

The DBMS_TDB package reports whether a database can be transported between platforms using the RMAN CONVERT DATABASE command. The package verifies that databases on the current host platform are of the same endian format as the destination platform, and that the state of the current database does not prevent transport of the database.

Overview

In many cases, Oracle supports transporting databases between platforms which have the same endian format. However, even when the endian formats are the same, a database must undergo a conversion process to move from one platform to another. There are also preconditions required for the process of transporting a database, such as having the database to be transported open read-only.

The DBMS_TDB package serves two purposes:

• Confirming that Oracle supports transporting a database from a given source platform to a given target platform

• Determining whether a database to be transported has been properly prepared for transport, and if not, identifying the condition that prevents database transport

The actual conversion is performed using the Recovery Manager CONVERT DATABASE command. For a complete discussion of the requirements for transporting a database, the process of converting a database for transport across platforms, and examples of the use of the DBMS_TDB subprograms in the conversion process, see Oracle Database Backup and Recovery User's Guide.

 

CHECK_EXTERNAL Function

This function determines whether a database has external tables, directories, or BFILEs.

Syntax

DBMS_TDB.CHECK_EXTERNAL

   RETURN BOOLEAN;

Return Values

If the database has external tables, directories, or BFILEs, return TRUE. Otherwise, return FALSE.

Usage Notes

• If SERVEROUTPUT is ON, then the function will output the names of the external tables, directories, and BFILEs in the database.

• The database must be open read-write.

Examples

This example illustrates the use of CHECK_EXTERNAL with a database that has several external tables, directories, and BFILEs:

SQL> SET SERVEROUTPUT ON

SQL> DECLARE

        external BOOLEAN;

     BEGIN

       external := DBMS_TDB.CHECK_EXTERNAL;

     END;

     /

The following external tables exist in the database:

SH.SALES_TRANSACTIONS_EXT

The following directories exist in the database:

SYS.MEDIA_DIR, SYS.DATA_FILE_DIR, SYS.LOG_FILE_DIR, SYS.DATA_PUMP_DIR

The following BFILEs exist in the database:

PM.PRINT_MEDIA

 

PL/SQL procedure successfully completed.