This article shows you how to create unique constraints using SQL Server Management Studio and Transact-SQL.
CREATE UNIQUE INDEX UQ_Email语句用于创建一个唯一索引,名为UQ_Email。 ON Employees (Email)指定了索引是在Employees表的Email字段上创建的。 如果想使用唯一约束来实现一样的目的,也可以如下操作: ALTERTABLEEmployeesADDCONSTRAINTUQ_EmailUNIQUE(Email); 1. 2. ALTER TABLE Employees用于修改已有的表结构。 ADD C...
For more information, see Unique Constraints and Check Constraints and Primary and Foreign Key Constraints. Index independent of a constraint Multiple unique nonclustered indexes can be defined on a table. For more information, see CREATE INDEX (Transact-SQL). Indexed view To create an indexed view...
IUniqueConstraint CreateUniqueConstraint(Microsoft.SqlServer.Management.SqlParser.Metadata.ITabular parent, Microsoft.SqlServer.Management.SqlParser.Metadata.IRelationalIndex index); Parameters parent ITabular index IRelationalIndex Returns IUniqueConstraint Applies to 產品版本 Micros...
MySQL / SQL Server / Oracle / MS Access: CREATE TABLE Persons ( Id_P int NOT NULL, LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255),CONSTRAINTuc_PersonIDUNIQUE(Id_P,LastName)) SQL UNIQUE Constraint on ALTER TABLE...
A unique index, UNIQUE constraint, or PRIMARY KEY constraint cannot be created if duplicate key values exist in the data. A unique nonclustered index can contain included nonkey columns. For more information, seeCreate an index with included columns. ...
Package: Microsoft.SqlServer.SqlManagementObjects v150.18208.0 C# Copy public Microsoft.SqlServer.Management.SqlParser.Metadata.IUniqueConstraint CreateUniqueConstraint(Microsoft.SqlServer.Management.SqlParser.Metadata.ITabular parent, Microsoft.SqlServer.Management.SqlParser.Metadata.IRelat...
2)SQL约束(6 个) (1)NOT NULL(一种写法) createtablecourse( cidintnotnull,cnamevarchar(255), tidint); (2)UNIQUE(三种写法) createtablecourse( cidintnotnull, cnamevarchar(255)notnullunique,tidint,unique(cid),CONSTRAINTuc_courseIDunique(cid, tid)--命名多列约束); ...
] type_name [ (precision [ , scale ]) ] <column_constraint> ::= [ CONSTRAINT constraint_name ] { { PRIMARY KEY | UNIQUE } { NONCLUSTERED | NONCLUSTERED HASH WITH ( BUCKET_COUNT = bucket_count ) } [ ( <column_name> [ ,... n ] ) ] | [ FOREIGN KEY ] REFERENCES [ schema_...
SQL Copy INSERT INTO dbo.DocExc (ColumnD) VALUES (49); Next, attempt to add values that fail the check constraint. SQL Copy INSERT INTO dbo.DocExc (ColumnD) VALUES (55); Related content ALTER TABLE (Transact-SQL) ALTER TABLE column_constraint (Transact-SQL) Unique constraints and ...