[CONSTRAINT constraint_name(约束名)] <约束类型> 约束不指定名称时,系统会给定一个名称。 在SQL Server 2005中有6种约束:主键约束(primary key constraint)、惟一性约束(unique constraint)、检查约束(check constraint)、默认约束(default constraint)、外部键约束(foreign key constraint)和空值(NULL)约束。 PRIMARY...
alter table 表名 add constraint 约束名称 约束类型 (列名) references 被引用的表名称(列名) 例子: alter table emp add constraint jfkdsj foreign key (did) references dept (id) SQL常用命令使用方法: 数据记录筛选: select*from Products:查询出Products表里面的所有信息 select ProductID,ProductName from P...
ALTER TABLE HumanResources.EmployeeDepartmentHistory CHECK CONSTRAINT FK_EmployeeDepartmentHistory_Department_DepartmentID; GO H. 重建資料分割索引 下列範例會重建 5 資料庫中分割區索引 IX_TransactionHistory_TransactionDate 的單一分割區,分割區編號是 AdventureWorks2022。 分割區 5 在 ONLINE=ON 重建,而且低優先...
Alter table [表名] add constraint [ 约束名] unique([列名])6：添加表中某列的默认值 Alter table [表名] add constraint [约束名] default(默认值) for [列名]7：添加约束 Alter table [表名] add constraint [约束名] check (内容)8:添加外键约束 Alter table [表名] add constraint [约束名] ...
ADD CONSTRAINT constraint_name constraint_type (column_name); ALTER TABLE table_name ENABLE/DISABLE TRIGGER trigger_name; 在PostgreSQL中,ALTER命令也提供了类似的功能,并且还允许重命名列: ALTER TABLE table_name RENAME COLUMN old_column_name TO new_column_name; ...
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); ...
SERVER ROLE SERVICE SERVICE MASTER KEY SYMMETRIC KEY TABLE テーブル カラム制約 TABLE column_definition TABLE computed_column_definition TABLE index_option TABLE table_constraint TRIGGER USER VIEW WORKLOAD GROUP XML SCHEMA COLLECTION バックアップと復元 CREATE 照合順序 DROP アクセス許可 サービスブ...
For more information, see the SQL Server and Azure SQL index architecture and design guide. If a table is in a transactional replication publication, you can't disable an index that is associated with a primary key constraint. These indexes are required by replication. To disable such an ...
Sintaxis para SQL Server, Azure SQL Database y Azure SQL Instancia administrada.syntaxsql Copiar ALTER INDEX { index_name | ALL } ON { REBUILD { [ PARTITION = ALL [ WITH ( <rebuild_index_option> [ , ...n ] ) ] ] | [ PARTITION = partition_number [ WITH ( <single_partition...
Only the rows violating the uniqueness constraint fails. OFF An error message occurs when duplicate key values are inserted into a unique index. The entire INSERT operation is rolled back.IGNORE_DUP_KEY can't be set to ON for indexes created on a view, non-unique indexes, XML indexes, ...