This article shows you how to create unique constraints using SQL Server Management Studio and Transact-SQL.
You can create a check constraint in a table to specify the data values that are acceptable in one or more columns in SQL Server by using SQL Server Management Studio or Transact-SQL. For more information on adding column constraints, see ALTER TABLE column_constraint. For more information, ...
Use SQL Server Management Studio In Object Explorer, right-click the table to which you want to add a unique constraint, and selectDesign. InTable Designer, select the row selector for the database column you want to define as the primary key. If you want to select multiple columns, hold...
可以使用 SQL Server Management Studio 或 Transact-SQL 在表中创建检查约束,以指定 SQL Server 的一个或多个列中可接受的数据值。 要详细了解如何添加列约束,请参阅 ALTER TABLE column_constraint。 有关详细信息,请参阅 Unique 约束和 check 约束。 备注 若要查询现有的检查约束,请使用 sys.check_constraints...
Use SQL Server Management Studio InObject Explorer, expand the table to which you want to add a check constraint, right-clickConstraintsand selectNew Constraint. In theCheck Constraintsdialog box, select in theExpressionfield and then select the ellipses(...). ...
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); ...
Transact-SQL 구문 표기 규칙 구문 syntaxsql 복사 CREATE TABLE { database_name.schema_name.table_name | schema_name.table_name | table_name } ( { <column_definition> } | <computed_column_definition> | <column_set_definition> | [ ] [ ,... n ] | [ ] } [ ,...
有关Windows 和 SQL 排序规则名称的详细信息,请参阅 Windows 排序规则名称和SQL 排序规则名称。 有关详细信息,请参阅 COLLATE。 约束 可选关键字,表示 PRIMARY KEY、NOT NULL、UNIQUE、FOREIGN KEY 或 CHECK 约束定义的开始。 constraint_name 约束的名称。 约束名称必须在表所属的架构中唯一。 NULL |NOT NULL ...
syntaxsql 複製 <function_option> ::= { [ ENCRYPTION ] | [ SCHEMABINDING ] | [ RETURNS NULL ON NULL INPUT | CALLED ON NULL INPUT ] | [ EXECUTE_AS_Clause ] | [ INLINE = { ON | OFF } ] } ::= ( { <column_definition> <column_constraint> | <computed_column_definition> } [...
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...