Check constraints contain an expression the database will evaluate when you modify or insert a row. If the expression evaluates to false, the database will not save the row. Building a check constraint is similar to building a WHERE clause. You can use many of the same operators (>, <, ...
本文转自:https://stackoverflow.com/questions/14229277/sql-server-2008-get-table-constraints You should use the currentsyscatalog views (if you're on SQL Server2005or newer - thesysobjectsviews aredeprecatedand should be avoided) - check out theextensive MSDN SQL Server Books Online documentation ...
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. ...
This article shows you how to create unique constraints using SQL Server Management Studio and Transact-SQL.
PERIOD FOR SYSTEM_TIME([ValidFrom], [ValidTo]) ) ON [PRIMARY] /* Create aligned primary key */ ALTER TABLE [dbo].[Staging_Department_Partition2] ADD CONSTRAINT [Staging_Department_Partition2_PK] PRIMARY KEY CLUSTERED ([DeptID] ASC) ON [PRIMARY]; /* Create and enforce const...
UNIQUE constraints and CHECK constraints are two types of constraints that can be used to enforce data integrity.
如果OLE DB 提供程序支持 OLE DB 2.6 架构行集 CHECK,则 SQL Server 查询优化器还会使用远程数据源中基表上定义的 CHECK_CONSTRAINTS_BY_TABLE 约束。 架构行集的 CHECK_CLAUSE 列应返回符合 SQL-92 语法的 CHECK 子句谓词。 查询优化器使用约束信息来消除或简化已知始终为 false 或始终为 true 的谓词,...
You can create a unique constraint in SQL Server by using SQL Server Management Studio or Transact-SQL to ensure no duplicate values are entered in specific columns that don't participate in a primary key. Creating a unique constraint automatically creates a corresponding unique index....
CHECK constraints Related tasks UNIQUE constraints Constraints are rules that the SQL Server Database Engine enforces for you. For example, you can useUNIQUEconstraints to make sure that no duplicate values are entered in specific columns that don't participate in a primary key. Although both aUN...
Check constraints Temporal tables Tutorials Reference Track changes Triggers User-defined functions Views XML data Development Internals & architecture Installation Migrate & load data Manage, monitor, & tune Query data Reporting & Analytics Security Tools Tutorials SQL Server on Linux SQL on Azure Azure...