操作表的约束简单介绍 完整性的约束关键字 含义 NOT NULL约束字段值不能为空 DEFAULT约束字段的默认值 UNIQUE KEY(UK)约束字段的值是唯一的PRIMARY KEY(PK)约束字段为表的主键,可以作为该表记录的唯一标识 AUTO_INCREMENT约束字段的值为自动增加 FOREIGN KEY(FK)约束字段为表的外键原表及展示:设置非空约束:NOT ...
简而言之,第一范式就是无重复的域。...; 1.主键约束:primary key 一个或多个字段的组合,填入的数据必须能在本表中唯一标识本行;必须提供数据,即NOT NULL; 一个表只能存在一个 2.外键约束:foreign...5.唯一约束:unique 一个或多个字段的组合,填入的数据必须能在本表中唯一标识本行;允许为NULL...
Yes but the default configuration values of Suhosin are known to cause problems with some operations, for example editing a table with many columns and no primary key or with textual primary key. Suhosin configuration might lead to malfunction in some cases and it can not be fully avoided as ...
Yes but the default configuration values of Suhosin are known to cause problems with some operations, for example editing a table with many columns and no primary key or with textual primary key. Suhosin configuration might lead to malfunction in some cases and it can not be fully avoided as ...
Yes but the default configuration values of Suhosin are known to cause problems with some operations, for example editing a table with many columns and no primary key or with textual primary key. Suhosin configuration might lead to malfunction in some cases and it can not be fully avoided as ...
Yes but the default configuration values of Suhosin are known to cause problems with some operations, for example editing a table with many columns and no primary key or with textual primary key. Suhosin configuration might lead to malfunction in some cases and it can not be fully avoided as ...
Yes but the default configuration values of Suhosin are known to cause problems with some operations, for example editing a table with many columns and no primary key or with textual primary key. Suhosin configuration might lead to malfunction in some cases and it can not be fully avoided as ...
Created a new database inviroment and installed a new version of concrete5 on to de database. When uploading the exported .sql file i get a error #1062 - Duplicate entry '1' for key 'PRIMARY' Reply InMotionFan says: May 15, 2015 at 9:39 pm Hello Minkoko, Sorry to hear you’...
Yes but the default configuration values of Suhosin are known to cause problems with some operations, for example editing a table with many columns and no primary key or with textual primary key. Suhosin configuration might lead to malfunction in some cases and it can not be fully avoided as ...
PRIMARY KEY (`railID`), INDEX `fk_rails_rooms1_idx` (`rooms_roomID` ASC) VISIBLE, CONSTRAINT `fk_rails_rooms1` FOREIGN KEY (`rooms_roomID`) REFERENCES `practice`.`rooms` (`roomID`) ON DELETE NO ACTION ON UPDATE NO ACTION)