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Oracle 参数 ALLOW_ROWID_COLUMN_TYPE 官方解释，作用，如何配置最优化建议

本站中文解释

:

ALLOW_ROWID_COLUMN_TYPE参数用于控制是否允许Oracle数据库中在每列定义一个ROWID类型值，以便跟踪表中具体记录。该参数允许在表中使用ROWID列以替代一个普通列，可以帮助提高查询的效率。

它是一个系统参数，默认为FALSE，如果希望使用ROWID类型，可以将其设置为TRUE。

要正确设置ALLOW_ROWID_COLUMN_TYPE参数，你必须先按CTRL+S键保存当前更改，然后按F9键以实际生效。你还可以使用以下SQL语句将参数设置为TRUE：

ALTER SYSTEM SET ALLOW_ROWID_COLUMN_TYPE = TRUE SCOPE=SPFILE;

官方英文解释

ALLOW_ROWID_COLUMN_TYPE determines whether table columns of data type ROWID are allowed to be created.

Note:

This parameter is valid only for Oracle Autonomous Database on dedicated Exadata infrastructure. On other types of Oracle databases, the value of this parameter is ignored and ROWID columns are always allowed to be created.

Property Description

Parameter type

Boolean

Default value

false

Modifiable

ALTER SESSION, ALTER SYSTEM

Modifiable in a PDB

Yes

Range of values

true | false

Basic

No

Oracle RAC

Multiple instances should use the same value

Values:

  • false

    Columns of data type ROWID are not allowed.

    You cannot specify ROWID columns when creating tables, nor can you add ROWID columns to existing tables. If the value of this parameter is changed from true to false at a time when ROWID columns exist in the database, then those columns are allowed to remain. However, Oracle recommends that you leave this parameter set to its default value of false and avoid introducing ROWID columns into Oracle Autonomous Database on dedicated Exadata infrastructure.

  • true

    Columns of data type ROWID are allowed.

    If you choose this setting, be aware that ROWID columns are incompatible with rolling upgrade operations and other internal operations that physically move table rows. At a minimum, database activities involving ROWID columns should be suspended during upgrades. Applications using ROWID columns should introduce correctness validation to mitigate against logical errors in the application if a row relocates.


数据运维技术 » Oracle 参数 ALLOW_ROWID_COLUMN_TYPE 官方解释，作用，如何配置最优化建议
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