Question

我现在尝试用外键链接我的表，但是下面的表我有一些问题。

我的表格

app.controller('MainCtrl', function($scope) {

  // need to define model in parent and pass to directive
  $scope.locationText = {
    value: ''
  };

  $scope.reset = function(){
    $scope.locationText.value = '';
  }

});

 app.directive('smartGooglemaps', function() {
    return {
      restrict:'E',
      replace:false,
      // transclude:true,
      scope: {
        locationgoogle: '=',
        locationText: '='
      },

      // ng-model="locationText.value"
      template: '<input id="google_places_ac" placeholder="Please enter a location" name="google_places_ac" type="text" class="input-block-level" ng-model="locationText.value"/>',

      link: function($scope, elm, attrs){

          // implement directive googlemaps logic, set text value etc.

          $scope.locationText.value = 'foo';

      }
  }
})

现在我想创建一个外键：

table users
- user_id INT(8) AUTO_INCREMENT //this is completly underlined
- username VARCHAR(150)
- password VARCHAR(50)
- auth_lvl VARCHAR(10) //this is "half underlined"
- ...

PRIMARY KEY: user_id
-------------------------------------------------
table groups
- group_id INT(11) AUTO_INCREMENT
- group_name VARCHAR(30)
- group_desc VARCHAR(60)

PRIMARY KEY: group_id
-------------------------------------------------
table users_groups
- user_id INT(10)
- group_id INT(10)

PRIMARY KEY: user_id, group_id (command was: PRIMARY KEY(user_id, group_id)
INDEX: group_id (these are seperated)
INDEX: user_id (these are seperated)

错误是：

ALTER TABLE `users_groups` 
    ADD FOREIGN KEY (`user_id`) 
        REFERENCES `DB`.`users` (`user_id`) 
        ON DELETE CASCADE 
        ON UPDATE RESTRICT

我想创建的第二个外键：

#1452 - Cannot add or update a child row: a foreign key constraint fails
(`db`.<result 2 when explaining filename '#sql-censored'>, CONSTRAINT 
`#sql-censored` FOREIGN KEY (`user_id`) REFERENCES `users` (`user_id`) 
ON DELETE CASCADE)

错误是：

ALTER TABLE `users_groups` 
    ADD FOREIGN KEY (`group_id`) 
        REFERENCES `DB`.`groups` (`group_id`) 
        ON DELETE CASCADE 
        ON UPDATE RESTRICT

这些有什么问题？我找不到错误：/

Answer 1

第一个似乎表明您的表中的数据不满足外键约束。第二个可能是由不同的数据类型INT（10）与INT（11）引起的。可能为所有列指定INTEGER将解决此问题。

Answer 2

<强>解决方案

我在users_groups中有一些行，其中user_id是用户的id，不再是users表格中的。

我删除了users中不存在的这些值后，一切正常！

MySQL错误＃1452 +创建外键时出错

2 个答案: