ALTER TABLE表名 MODIFY字段名 字段名描述; 给表里的字段加上约束条件 ALTER TABLE 表名 ADD CONSTRAINT 约束名 PRIMARY KEY (字段名); ALTER TABLE 表名 ADD CONSTRAINT 约束名 UNIQUE (字段名); 把表放在或取出数据库的内存区 ALTER TABLE 表名 CACHE; ALTER TABLE 表名 NOCACHE; 3.DROP (删除表, 索引...
3. 3. 使用ALTER TABLE语句修改字段长度 使用ALTER TABLE命令来修改字段的长度。以下是修改字段的具体代码: -- 修改字段长度ALTERTABLEemployeesALTERCOLUMNlast_nameVARCHAR(100);-- 这条语句将employees表中的last_name字段的长度修改为100 1. 2. 3. 4. 4. 验证修改是否成功 可以使用sp_help命令来查看表的结构...
CREATETABLEdbo.doc_exy (column_aINT); GOINSERTINTOdbo.doc_exy (column_a)VALUES(10); GOALTERTABLEdbo.doc_exyALTERCOLUMNcolumn_aDECIMAL(5,2); GO 有关使用ALTER TABLE修改列的详细信息,请参阅ALTER TABLE column_definition。 下一步 ALTER TABLE (Transact-SQL) ...
= 50 ' Create the index on the instance of SQL Server. idx.Create() ' Modify the page locks property. idx.DisallowPageLocks = True ' Run the Alter method to make the change on the instance of SQL Server. idx.Alter() ' Remove the index from the table. idx.Drop() ...
ALTER TABLE modifies a table definition by altering, adding, or dropping columns and constraints. ALTER TABLE also reassigns and rebuilds partitions, or disables and enables constraints and triggers.
ALTER TABLE modifies a table definition by altering, adding, or dropping columns and constraints. ALTER TABLE also reassigns and rebuilds partitions, or disables and enables constraints and triggers.
What is SQL Server? Connect to the Database Engine What's new? Editions and features Release notes Business continuity Database design Hierarchical Data Collation Databases Event notification FILESTREAM, FileTable & BLOB Indexes SQL Graph Sequence numbers ...
The option on the column. The DataType has to be null for this to be AddRowguidcol or DropRowguidcol. (?)PERSISTED used only in 2005" C# Copiar public Microsoft.SqlServer.TransactSql.ScriptDom.AlterTableAlterColumnOption AlterTableAlterColumnOption { get; set; } ...
ALTER TABLE modifies a table definition by altering, adding, or dropping columns and constraints. ALTER TABLE also reassigns and rebuilds partitions, or disables and enables constraints and triggers.
设置SQL Server、Azure SQL 数据库 和 Azure Synapse Analytics 中的数据库选项。 有关其他 ALTER DATABASE 选项,请参阅 ALTER DATABASE。备注 使用ALTER DATABASE 设置某些选项可能需要独占数据库访问权限。 如果 ALTER DATABASE 语句未及时完成,请检查数据库中的其他会话是否正在阻止 ALTER DATABASE 会话。有关语法...