Azure SQL 資料庫 Azure SQL 受控執行個體 UNIQUE和CHECK是兩種類型的條件約束,可用來強制執行 SQL Server 資料表中的資料完整性。 這些都是重要的資料庫物件。 本文包含下列章節。 UNIQUE 條件約束 CHECK 條件約束 相關工作 UNIQUE 條件約束 條件約束是 SQL Server 資料庫引擎為您...
如需資料行層級 CHECK 條件約束,請參閱sys.check_constraints (Transact-SQL)。 is_sparsebit1 = 資料行是疏鬆數據行。 如需詳細資訊,請參閱使用疏鬆資料行。 is_column_setbit1 = 資料行是資料行集。 如需詳細資訊,請參閱使用資料行集。 generated_always_typetinyint適用於:SQL Server 2016 (13...
有关列级 CHECK 约束,请参阅sys.check_constraints (Transact-SQL)。 is_sparsebit1 = 列为稀疏列。 有关详细信息,请参阅使用稀疏列。 is_column_setbit1 = 列为列集。 有关详细信息,请参阅使用列集。 generated_always_typetinyint适用于:SQL Server 2016 (13.x) 及更高版本、SQL 数据库。 7、8、...
controls used to validate data changes at the Publisher, such as constraints, should be present at the Subscriber or should be handled in the application. For information about replication agents and constraints at the Subscriber, seeControlling Constraints, Identities, and Triggers with NOT FOR ...
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Learn about SQl Constraints namely Not Null, Unique, Check, Primary Key and Foriegn Key in this tutorial.
Note that this implementation is for immediately-checked constraints only. Deferred constraints -- i.e. constraints that are checked at transaction-end rather than statement-end are another task and will be implemented for all constraint types (not just foreign key constraints) when the time comes...
Scope of rows:all constraints Ordered byschema, table name, constraint type Sample results QueryColumnsRowsSample results Confused about your SQL Server database? You don't have to be. There's an easy way to understand the data in your databases. ...
Physical database design is the process of producing a description of the database (often in terms of DDL scripts, for example) in terms of secondary storage. It will include descriptions of the base tables and views, the indexes, constraints, and so on.Sidebar...
116 12.2. Unique Constraints ... 119 12.3. Column ... 120 12.4. Identity