Create a unique constraint on a nullable columnIn Object Explorer, connect to an instance of Database Engine. On the Standard bar, select New Query. Copy and paste the following example into the query window and select Execute. The example creates a filtered unique constraint using the CREATE ...
Create a unique constraint on a nullable column In Object Explorer, connect to an instance of Database Engine. On the Standard bar, select New Query. Copy and paste the following example into the query window and select Execute. The example creates a filtered unique constraint using the CREATE...
创建Primary Key altertable[TableName]addconstraint[PK_PrimaryKey]primarykeyclustered(Id); Edit Column Type ALTERTABLE[Product]ALTERCOLUMN[Name]nvarchar(max); Rename rename table 和 column 是很恐怖的操作. 因为 index, foreign key 都会用 table name 和 column name 命名. 所以它需要批量换 EXECsp_rena...
sysi.is_unique as '索引是否要求唯一',sysc.is_nullable as '索引是否允许为空',sysi.is_primary_key as '是否是主键约束',sysi.is_unique_constraint as '是否是唯一约束', sysk.create_date, sysk.modify_date from sys.indexes sysi left join sys.key_constraints sysk on sysi.object_id=sysk.pare...
AlterServerRoleStatement AlterServiceMasterKeyOption AlterServiceMasterKeyStatement AlterServiceStatement AlterSymmetricKeyStatement AlterTableAddTableElementStatement AlterTableAlterColumnOption AlterTableAlterColumnStatement AlterTableAlterIndexStatement AlterTableAlterPartitionStatement AlterTableChangeTrackingModificati...
Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Specifies the properties of a PRIMARY KEY, FOREIGN KEY, UNIQUE, or CHECK constraint that is part of a new column definition added to a table by using ALTER TABLE. Napomena For Microsoft Fabric, visit ALTER TABLE column_...
当动态添加 表的 列时,如果设置了该列的 默认值,那么再用alter table TableName drop column ColumnName语句时就会报错,因为存在了default约束。 1.查找出表中该列的约束名称 declare @name varchar(50) select @name = from sysobjects b join syscolumns a on = a.cdefault ...
SQ = 服务队列TA = 程序集 (CLR) DML 触发器TF = SQL table-valued-functionTR = SQL DML 触发器TT = 表类型UQ = UNIQUE 约束X = 扩展存储过程适用于:SQL Server 2014 (12.x) 及更高版本、Azure SQL Database、Azure Synapse Analytics、Analytics Platform System (PDW) 。ST = STATS_TREE适用于:...
描述:當取用者使用 DBCOLUMNDESC 的 wType成員定義數據行數據類型時,SQL Server Native Client OLE DB 提供者會使用DBPROP_COL_FIXEDLENGTH 來判斷數據類型對應。 如需詳細資訊,請參閱ITableDefinition 中的資料類型對應。 DBPROP_COL_NULLABLER/W︰讀取/寫入 ...
AlterServerRoleStatement AlterServiceMasterKeyOption AlterServiceMasterKeyStatement AlterServiceStatement AlterSymmetricKeyStatement AlterTableAddTableElementStatement AlterTableAlterColumnOption AlterTableAlterColumnStatement AlterTableAlterIndexStatement AlterTableAlterPartitionStatement A...