151 DBMS_TDB

DBMS_TDB包报告是否可以使用RMAN CONVERT database命令在平台之间传输数据库。包验证当前主机平台上的数据库是否与目标平台具有相同的端口号格式，以及当前数据库的状态是否阻止数据库的传输。

Using DBMS_TDB

This section contains topics which relate to using DBMS_TDB.

Overview
Constants
Views
Operational Notes

Overview

在许多情况下，Oracle支持在具有相同endian格式的平台之间传输数据库。然而，即使endian格式相同，数据库也必须经过转换过程才能从一个平台转移到另一个平台。传输数据库的过程还需要一些先决条件，比如将数据库以只读方式打开传输。

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.

Security Model

Use of this package requires the DBA privilege.

Constants

DBMS_TDB包定义了几个应用于指定参数值的枚举常量。枚举常量必须以包名作为前缀，例如，DBMS_TDB.SKIP_NONE。

The DBMS_TDB package uses the constants shown in Table 151-1.

Table 151-1 DBMS_TDB Constants

Name	Type	Value	Description
`SKIP_NONE`	`NUMBER`	`0`	Check all files when checking whether a database is ready for transport.
`SKIP_OFFLINE`	`NUMBER`	`2`	Skip files in offline tablespaces when checking whether a database is ready for transport.
`SKIP_READONLY`	`NUMBER`	`3`	Skip files in readonly tablespaces when checking whether a database is ready for transport.

Views

The DBMS_TDB package uses the following view listed in Oracle Database Reference:

V$DB_TRANSPORTABLE_PLATFORM, which specifies which combinations of source and target platforms support database transport

Operational Notes

The subprograms in this package are useful both in determining whether the desired cross-platform database conversion is possible, and in checking whether the database is ready for conversion. See Oracle Database Backup and Recovery User's Guide for details on the different uses of these subprograms are used in the conversion process.
The subprograms in this package return simple TRUE or FALSE results to indicate whether database transport is possible. Use the subprograms with SERVEROUTPUT ON for informative messages about why transport is not possible.

Summary of DBMS_TDB Subprograms

Table 151-2 DBMS_TDB Package Subprograms

Subprogram	Description
CHECK_DB Function	检查是否可以将数据库传输到目标平台
CHECK_EXTERNAL Function	检查数据库是否具有外部表、目录或BFILEs

CHECK_DB Function

此函数检查是否可以将数据库传输到目标平台。它测试对于给定的源和目标平台是否支持传输，以及数据库当前是否处于传输的正确状态。
如果不打算传输数据库的只读或脱机部分，可以指定是否跳过检查。
函数重载。每种语法形式的不同功能和定义一起给出。

Syntax

DBMS_TDB.CHECK_DB (target_platform_name   IN VARCHAR2, skip_option            IN  NUMBER)RETURN BOOLEAN;DBMS_TDB.CHECK_DB (target_platform_name   IN VARCHAR2)RETURN BOOLEAN;DBMS_TDB.CHECK_DB RETURN BOOLEAN;

Parameters

Table 151-3 CHECK_DB Function Parameters

Parameter	Description
`target_platform_name`	The name of the destination platform, as it appears in `V$DB_TRANSPORTABLE_PLATFORM`.
`skip_option`	Specifies which, if any, parts of the database to skip when checking whether the database can be transported. Supported values are listed in Table 151-1, "DBMS_TDB Constants".

Return Values

If the database cannot be transported to the target platform or is not ready to be transported, returns FALSE. If the database is ready for transport, returns TRUE.

Usage Notes

If SERVEROUTPUT is ON, then the output will contain the reasons why the database cannot be transported and how to fix the problems. For details on possible reasons and fixes, see Table 151-4, "Reasons for CHECK_DB Function to Return FALSE".

Table 151-4 Reasons for CHECK_DB Function to Return FALSE

Cause	Action
Unrecognized target platform name.	Check `V$DB_TRANSPORTABLE_PLATFORM` for recognized platform names.
Target platform has a different endian format.	Conversion is not supported.
Database is not open read-only.	Open database read-only and retry.
There are active or in-doubt transactions in the database.	Open the database read-write. After the active transactions are rolled back, open the database read-only and retry the operation. This situation can occur if users flash back the database and open it read only. The active transactions will be rolled back when the database is opened read-write.
Deferred transaction rollback needs to be done.	Open the database read-write and bring online the necessary tablespaces. Once the deferred transaction rollback is complete, open the database read-only and retry the operation.
Database compatibility version is below 10.0.0.	Change the `COMPATIBLE` initialization parameter to 10.0.0 or higher, open the database read-only, and retry the operation.
Some tablespaces have not been open read-write with compatibility version is 10.0.0 or higher.	Change the `COMPATIBLE` initialization parameter to 10.0.0 or higher, then open the affected tablespaces read-write. Shut down the database, open it read-only, and retry the operation.

Examples

This example illustrates the use of CHECK_DB with a database that is open read-write:

SQL> SET SERVEROUTPUT ON
SQL> DECLAREdb_ready BOOLEAN;BEGINdb_ready := DBMS_TDB.CHECK_DB('Microsoft Windows IA (32-bit)');END;/Database is not open READ ONLY. Please open database READ ONLY and retry.PL/SQL procedure successfully completed.

CHECK_EXTERNAL Function

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