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Oracle 视图 DBA_LOGSTDBY_NOT_UNIQUE 官方解释，作用，如何使用详细说明

本站中文解释

Oracle视图DBA_LOGSTDBY_NOT_UNIQUE是数据库中包含非唯一LOB分区要求的数据表的系统查看视图。它显示由DBA创建的特定类型的表的条目，它们的行或分区未使用唯一的LOB存储分配机制。通过该视图，可以方便地检查文件系统中的使用情况，或者查看是否存在不应使用的LOB存储分配的情况。

使用方法: 如果要检查某个表是否使用非唯一LOB分配机制，则可以使用dba_logstdb_Not_unique视图。例如，可以执行下列查询：

SELECT table_name
FROM dba_logstdb_Not_unique
WHERE object_name = ”;

官方英文解释

DBA_LOGSTDBY_NOT_UNIQUE displays all tables that have no primary and no non-null unique indexes.

Most of the tables displayed by this view are supported because their columns contain enough information to be maintained in a logical standby database. Some tables, however, cannot be supported because their columns do not contain the necessary information. Unsupported tables usually contain a column defined using an unsupported data type.

In a CDB, the data displayed pertains to the container in which the view is queried.

Column Datatype NULL Description

OWNER

VARCHAR2(128)

Schema name of the non-unique table

TABLE_NAME

VARCHAR2(128)

Table name of the non-unique table

BAD_COLUMN

VARCHAR2(1)

  • Y – Table column is defined using an unbounded data type, such as LONG or BLOB. If two rows in the table match except in their LOB columns, then the table cannot be maintained properly. Log apply services will attempt to maintain these tables, but you must ensure the application does not allow uniqueness only in the unbounded columns.

  • N – Enough column information is present to maintain the table in the logical standby database but the log transport services and log apply services would run more efficiently if you added a primary key. You should consider adding a disabled RELY constraint to these tables.


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