The DROP COLUMN command is used to delete a column in an existing table.The following SQL deletes the "ContactName" column from the "Customers" table:ExampleGet your own SQL Server ALTER TABLE CustomersDROP COLUMN ContactName; DROP a UNIQUE Constraint...
The RazorSQL alter table tool includes a Drop Constraint option for dropping a constraint from a MS SQL Server database table. The drop constraint function allows the user to enter a constraint to drop from the table. The tool then generates the appropriate alter table drop constraint SQL comm...
The RazorSQL alter table tool includes a Drop Constraint option for dropping a constraint from a Informix database table. The drop constraint function allows the user to enter a constraint to drop from the table. The tool then generates the appropriate alter table drop constraint SQL command for...
生成SQL 片段以删除列的默认约束。 C# 复制 protected virtual void DropDefaultConstraint(string? schema, string tableName, string columnName, Microsoft.EntityFrameworkCore.Migrations.MigrationCommandListBuilder builder); 参数 schema String 包含表的架构。 tableName String 包含列的表...
set@sql=N'alter table [system] drop constraint DF_system_LastGraceDate' execsp_executesql@sql 如果我们不知道constraint name,我们可以先把他们找出来,然后再remove掉。 代码 --create alter table command as string and run it declare@sqlnvarchar(1024) ...
set@sql=N'alter table [system] drop constraint DF_system_LastGraceDate' execsp_executesql@sql 如果我们不知道constraint name,我们可以先把他们找出来,然后再remove掉。 代码 --create alter table command as string and run it declare@sqlnvarchar(1024) ...
The DROP TABLE command cannot be used to delete a table that isreferenced by a foreign key constraint. Thereferencing FOREIGN KEY constraintor the referencing table must be deleted first. If both the referencing table and the table with the primary key are being deleted in the same DROP TABLE...
TSqlTriggerEventTypeHelper UnaryExpression UnaryExpressionType UniqueConstraintDefinition UniqueRowFilter UnpivotedTableReference UnqualifiedJoin UnqualifiedJoinType UpdateCall UpdateDeleteSpecificationBase UpdateForClause UpdateMergeAction UpdateSpecification UpdateStatement ...
The below syntax is used to remove multiple databases from the SQL Server is as follows: DROP DATABASE Database_Name_1, Database_Name_2, Database_Name_3, Database_Name_N; Examples of DROP Database in SQL We will execute the SHOW DATABASES command to check which databases are residing ...
However, to drop a table that is referenced by a view or a foreign-key constraint of another table,CASCADEmust be specified. (CASCADEwill remove a dependent view entirely, but in the foreign-key case it will only remove the foreign-key constraint, not the other table entirely.) ...