1.删除主键 alter table ACC6 drop CONSTRAINT SYS_C0015557[主键名] 如果是alter table ACC6 drop primary key(aae002,aac001,aae140,aab001) 这在oracle执行是会出错的 2.增加主键 ALTER TABLE supplier add CONSTRAINT constr_pk[主键名] PRIMARY KEY (supplier_id[列名]); 如alter table ACC6 add CONSTR...
1.primary key ☆如果一个table有primary key,那么这个primary key 的value就不能为null,而且每条record就不能重复(完全相同),否则会发生如下错误 A.当primary key置为null时:ERROR 1048 (23000): Column 'id' cannot be null B.当primary key 重复时:ERROR 1062 (23000): Duplicate entry '1' for key '...
Oracle Database - Enterprise Edition - Version 10.1.0.2 and laterInformation in this document applies to any platform.Symptoms After import of a table that contains a primary key constraint and corresponding index, a drop constraint does not drop the corresponding PK index. When trying to insert...
在OceanBase 数据库 MySQL 模式以及 Oracle 模式中直接删除含主键的列可以通过先删除主键、再删除对应的列的方式,来实现删除主键列的目的。涉及的语句如下。 ALTER TABLE table_a DROP PRIMARY KEY; ALTER TABLE table_a DROP COLUMN ID; OceanBase 数据库 MySQL 模式下删除主键的操作。
Oracle Drop列 在本教程中,将学习如何使用Oracle删除列语句从表中删除一个或多个列。 Oracle使用SET UNUSED COLUMN子句删除列 从大表中删除列的过程可能耗费时间和资源。 因此,通常使用ALTER TABLE SET UNUSED COLUMN语句来逻辑删除列,如下所示: ALTER TABLE table_name...
SQL Server / Oracle / MS Access:ALTER TABLE Persons DROP CONSTRAINT PK_Person; MySQL:ALTER TABLE Persons DROP PRIMARY KEY; DROP a FOREIGN KEY ConstraintTo drop a FOREIGN KEY constraint, use the following SQL:SQL Server / Oracle / MS Access:...
[oracle@DB-Server ~]$ oerr ora 2429 02429, 00000, "cannot drop index used for enforcement of unique/primary key" // *Cause: user attempted to drop an index that is being used as the // enforcement mechanism for unique or primary key. ...
ORA-02291: integrity constraint (SYS.T_FK) violated - parent key not found (違反了constraint,員工基本資料表根本沒有3號這個員工,何來的銷售紀錄。) SQL> drop table t; drop table t * ERROR at line 1: ORA-02449: unique/primary keys in table referenced by foreign keys ...
primary key Cause:alter table drop primary key - primary key does not exist.Action: None ...
NOTE: A primary key (PK) is a constraint. Each set of values in its columns can only appear once. So you can't have duplicates. It also has a not null constraint. And creates a unique index in the background.To create one, add the organization index clause to the table definiti...