Oracle(二)DDL语句create、alert、drop、truncate 二.数据定义 (DDL) 部分 www.2cto.com 1 . CREATE (创建表, 索引, 视图, 同义词, 过程, 函数, 数据库链接等) ORACLE常用的字段类型有 CHAR 固定长度的字符串 VARCHAR2 可变长度的字符串 www.2cto.com NUMBER (M,N) 数字型M是位数总长度, N是小数...
Re: How to drop unique constraint 48078 Roland Bouman February 18, 2006 01:25PM Sorry, you can't reply to this topic. It has been closed. This forum is currently read only. You can not log in or make any changes. This is a temporary situation. ...
To drop a UNIQUE constraint, use the following SQL:SQL Server / Oracle / MS Access:ALTER TABLE Persons DROP CONSTRAINT UC_Person; MySQL:ALTER TABLE Persons DROP INDEX UC_Person; DROP a PRIMARY KEY ConstraintTo drop a PRIMARY KEY constraint, use the following SQL:...
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 ...
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 ...
ORA-02429 错误表示“cannot drop index used for enforcement of unique/primary key”,即无法删除用于强制执行唯一性或主键约束的索引。 2. 为什么会出现这个错误 在Oracle 数据库中,当为表定义唯一性约束(UNIQUE)或主键约束(PRIMARY KEY)时,数据库会自动创建一个索引来维护这些约束的完整性。如果尝试删除这个由数...
请注意,若要删除的限制是与索引有关的 (如UNIQUE),在 MySQL 上,我们需要使用DROP INDEX。 Oracle: ALTER TABLE Customer DROP CONSTRAINT Con_First; SQL Server: ALTER TABLE Customer DROP CONSTRAINT Con_First; SQL 主键>> 本页最近于 2023年12月29日更新 ...
[oracle@localhost ~]$ 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. ...
DATETIME数据类型在Oracle数据库环境中,表示为DATE类型。3.3.3 字符数据类型字符数据类型可以用来存储各种字母、数字符号和特殊符号。在SQL Server 2005中,字符数据类型包括字符串数据类型和Unicode数据类型。1.字符串数据类型字符串数据的类型包括char、varchar和text,它们都是非Unicode数据类型。字符数据是由任何字母、符号...
Re: How to drop unique constraint 48062 Roland Bouman February 18, 2006 01:25PM Sorry, you can't reply to this topic. It has been closed. Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily...