' NOCHECK CONSTRAINT ' + name FROM sysobjects WHERE xtype = 'F' ORDER BY object_name(parent_obj) and to enable: SELECT 'ALTER TABLE ' + object_name(parent_obj) + ' WITH CHECK CHECK CONSTRAINT ' + name FROM sysobjects WHERE xtype = 'F' ORDER BY object_name(parent_obj) ...
这表明当我们开启(enable)内部触发器的时候,PostgreSQL不会验证(validate)约束,因此也不会验证数据是否会有冲突,因为外键约束的状态始终是有效的。 我们需要做的是先将其变成无效的: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 postgres=# alter table t2 alter CONSTRAINT t2_b_fkey...
④外键约束: foreign key (简称FK) ⑤检查约束: check (mysql不支持,oracle支持) (一)非空约束:not null 非空约束约束的字段不能NULL。 语法:建表时在字段和数据类型后面加上约束 create table 表名( 字段名 数据类型 not null, ... ...); 1. 2. 3. 4. 案例: create table room4( id bigint n...
index, all incoming and outgoingFOREIGN KEYconstraints on the underlying table are also disabled. The constraint names are listed in a warning message when the index is disabled. After you rebuild the index, all constraints must be manually enabled by using theALTER TABLE CHECK CONSTRAINTstatement....
After you rebuild the index, all constraints must be manually enabled by using the ALTER TABLE CHECK CONSTRAINT statement. Nonclustered indexes are automatically disabled when the associated clustered index is disabled. They can't be enabled until either the clustered index on the table or view is...
SQL> create table test(id int, name varchar2(10)); Table created SQL> alter table test add constraint ck_id check(id > 10); Table altered 3测试1: Enable Validate SQL> alter table test Enable validate constraint ck_id; Table altered ...
T-SQL GETDATE() ? ADD and SUBTRACT depending on the condition is CASE STATEMENT ADD COLUMN to variable table? Add prefix in data column Add Time in SQL HH:MM:SS to another HH:MM:SS Adding a column to a large (100 million rows) table with default constraint adding a extra column in...
%SQL% 选中Drop,在右端的Value中写入 drop table if exists %VIEW% 选中Enable,在右端的Value中选择Yes 确定保存。 注意,此修改是修改了PowerDesigner程序的设置,只需要配置一次即可;但是它不对PDM文件做改动,没有修改过的PowerDesigner不能生成视图的SQL。
SQL> alter table a add constraint ck_a check (1=1) disable; Table altered. SQL> alter table a modify constraint ck_a disable validate; Table altered. --oracle 的语法真奇怪,前面我使用的是alter table a disable validate constraint ck_a;也可以。
When you create any Foreign Key on the table, internally It creates a hidden trigger for check data integrity. You should enable/disable the trigger for achieving disable foreign key constraint. Create a sample Student Master table: 1 2