altertablePersonsalterCOLUMNcityset DEFAULT'Renne'; 2、撤销表约束 需要之前有约束的命名,就是之前得是使用 CONSTRAINT 定义约束 1)UNIQUE、PRIMARY KEY、FOREIGN KEY、CHECK(一种写法) altertablePersonsdrop constraint约束名; 2)DEFAULT(一种写法) altertablePersonsalterCOLUMNCityDROPDEFAULT; 3、添加列 altertable...
CREATE TABLE dbo.doc_exe (column_a INT CONSTRAINT column_a_un UNIQUE) ; GO ALTER TABLE dbo.doc_exe ADD -- Add a PRIMARY KEY identity column. column_b INT IDENTITY CONSTRAINT column_b_pk PRIMARY KEY, -- Add a column that references another column in the same table. column_c INT NULL...
SQL Server、Azure SQL 数据库和Azure SQL 托管实例的语法。syntaxsql 复制 ALTER INDEX { index_name | ALL } ON { REBUILD { [ PARTITION = ALL [ WITH ( <rebuild_index_option> [ , ...n ] ) ] ] | [ PARTITION = partition_number [ WITH ( <single_partition_rebuild_index_option> ...
Transact-SQL 语法约定语法SQL Server、Azure SQL 数据库和Azure SQL 托管实例的语法。syntaxsql 复制 ALTER INDEX { index_name | ALL } ON { REBUILD { [ PARTITION = ALL [ WITH ( <rebuild_index_option> [ , ...n ] ) ] ] | [ PARTITION = partition_number [ WITH ( <single_partition_...
ALTER TABLE [Testowners] ALTER COLUMN [owner_id] [int] IDENTITY(1,1) NOT NULL PRIMARY KEY --allowed , if the column didn't exist ALTER TABLE [Testowners] ADD [owner_id2] [int] IDENTITY(1,1) NOT NULL PRIMARY KEY Lowell --help us help you! If you post a question, make sure yo...
SQL Server、Azure SQL 資料庫 和 Azure SQL 受控執行個體 的語法。syntaxsql 複製 ALTER INDEX { index_name | ALL } ON { REBUILD { [ PARTITION = ALL [ WITH ( <rebuild_index_option> [ , ...n ] ) ] ] | [ PARTITION = partition_number [ WITH ( <single_partition_rebuild_index_optio...
MySQL / SQL Server / Oracle / MS Access: ALTER TABLE PersonsADDCONSTRAINTpk_PersonIDPRIMARYKEY (Id_P,LastName) 注释:如果您使用 ALTER TABLE 语句添加主键,必须把主键列声明为不包含 NULL 值(在表首次创建时)。 撤销PRIMARY KEY 约束 如需撤销 PRIMARY KEY 约束,请使用下面的 SQL: ...
适用对象:SQL Server(从 SQL Server 2019 (15.x) 开始) 启用加速数据库恢复(ADR)。 默认情况下,ADR 在 SQL Server 2019 (15.x) 及更高版本中设置为 OFF。 使用此语法,可以为持久版本存储(PVS)数据指定特定的文件组。 如果未指定文件组,则 PVS 存储在 P...
CREATE TABLE MyCustomers (CustID INTEGER IDENTITY (100,1) PRIMARY KEY, CompanyName NvarChar (50)); INSERT INTO MyCustomers (CompanyName) VALUES ('A. Datum Corporation'); ALTER TABLE MyCustomers ALTER COLUMN CustId IDENTITY (200, 2);
DECLARE @x xml (ManuInstructionsSchemaCollection); GO --Or create a typed xml column. CREATE TABLE T ( i int primary key, x xml (ManuInstructionsSchemaCollection)); GO -- Clean up. DROP TABLE T; GO DROP XML SCHEMA COLLECTION ManuInstructionsSchemaCollection; Go USE master; GO DROP DAT...