ALTER TABLE 时的 SQL CHECK 约束 当表已被创建时,如需在 "P_Id" 列创建 CHECK 约束,请使用下面的 SQL: MySQL / SQL Server / Oracle / MS Access: ALTER TABLE Persons ADD CHECK (P_Id>0) 如需命名 CHECK 约束,并定义多个列的 CHECK 约束,请使用下面的 SQL 语法: MySQL / SQL Server / Oracle ...
status--是否启用 from user_constraints--[all_constraints|dba_constraints] where constraint_name='CHECK_TB_SUPPLIER_ID'; 8. 删除CHECK约束 8.1 语法 ALTERTABLE table_name DROPCONSTRAINT constraint_name; 8.2 示例 ALTERTABLE tb_supplier DROPCONSTRAINT check_tb_supplier_id;...
Create Named CHECK Constraint It's a good practice to createnamed constraintsso that it is easier to alter and drop constraints. Here's an example to create a namedCHECKconstraint: -- create a named constraint named amountCK-- the constraint makes sure that amount is greater than 0CREATETABLE...
Constraints on a table in Oracle can be found using the below views user_constraints: It provides information about constraints owned by the current user. all_constraints:shows information about constraints accessible to the current user, including those owned by other users. dba_constraints: provides...
Constraints have names. It is good practice to specify the names with a standard naming convention, but if they are not explicitly named, Oracle will generate names. 由上可知,每一个约束都有名称,最好的做法是在定义约束是显式的命名,如果没有显式命名,那么系统会提供一个名字。
SQL 型 V4.3.5 参考指南 系统视图 MySQL 租户系统视图 字典视图 information_schema.CHECK_CONSTRAINTS 更新时间:2025-01-30 23:00:01 编辑 功能 记录了CREATE TABLE操作时,有关表和列相关的约束信息。 说明 从V3.2.3 版本开始引入。 字段说明 字段名称类型是否可以为 NULL描述 ...
我测试了一下,事实证明是可以的,Oracle的Check Constraints可以通过imp,使用indexfile来获得,并且可以通过手工执行脚本来加载。 以下是一个简单的测试过程。创建测试表: [oracle@oracle ~]$ sqlplus EYGLE/EYGLE SQL*Plus: Release 10.2.0.5.0 - Production on Tue Jul 13 23:48:35 2010 ...
oracle数据库 如何查询某个表的约束条件 使用下面语句从all_constraints视图中查看某表上的约束: SELECT constraint_name, table_name, r_owner, r_constraint_name...all_constraints WHERE table_name = 'table_name' and owner = 'owner_name'; 另一个视图ALL_CONS_COLUMNS也包括组成表上约束列的信息 3.3K...
oracle database-design constraint check-constraints Share Improve this question Follow edited Sep 27, 2024 at 8:06 Martin Smith 87.2k1515 gold badges253253 silver badges347347 bronze badges asked Sep 26, 2024 at 13:41 mhabes 111 bronze badge Add a comment Know so...
the SQL mode in effect at evaluation time. If any component of the expressiondepends on the SQL mode, different results may occur for different uses of the table unless the SQL mode is the same during all uses. The Information Schema CHECK_CONSTRAINTStable...