ENABLE VALIDATE

最新推荐文章于 2024-08-07 11:52:49 发布

转载最新推荐文章于 2024-08-07 11:52:49 发布 · 182 阅读

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#数据库

本文详细介绍了在数据库中使用约束验证来确保数据完整性的方法。当启用并验证约束时，所有旧数据和新数据都必须符合该约束条件。如果表中的任意一行违反了完整性约束，则该约束保持禁用状态，并且Oracle会返回错误。此外，如果设置了主键约束并在ENABLE VALIDATE模式下进行验证，系统将检查主键列是否包含空值。

specifies that all old and new data also complies with the
constraint. An enabled validated constraint guarantees that all data is and will
continue to be valid.

If any row in the table violates the integrity constraint, the constraint remains
disabled and Oracle returns an error. If all rows comply with the constraint, Oracle
enables the constraint. Subsequently, if new data violates the constraint, Oracle
does not execute the statement and returns an error indicating the integrity
constraint violation.

If you place a primary key constraint in ENABLE VALIDATE mode, the validation
process will verify that the primary key columns contain no nulls. To avoid this
overhead, mark each column in the primary key NOT NULL before entering data
into the column and before enabling the primary key constraint of the table.

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