Yii2中如何使用Migration创建复合主键？

Posted 2023-03-14

【中文标题】Yii2中如何使用Migration创建复合主键？

【英文标题】：How to create composite primary key by using Migration in Yii2?

【发布时间】：2015-11-15 04:35:54

【问题描述】：

我尝试运行yii migrate，但它显示以下错误：

create table news-cate ...Exception: SQLSTATE[42000]: Syntax error or access violation: 1075 Incorrect table definition; there can be only one auto column and it must be defined as a key
The SQL being executed was: CREATE TABLE `news-cate` (
        `news-id` int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
        `cate-id` int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY

这是我的代码：

class m150821_083020_create_newscate_table extends Migration

    public function safeUp()
    
        $this->createTable('news-cate', [
            'news-id' => $this->primaryKey(),
            'cate-id' => $this->primaryKey(),
        ]);
        $this->addForeignKey("fk_news_cate_nid", "news-cate", "news-id", "news", "id", "RESTRICT", "CASCADE");
        $this->addForeignKey("fk_news_cate_cid", "news-cate", "cate-id", "category", "id", "RESTRICT", "CASCADE");
    

    public function safeDown()
    
        echo "m150821_083020_create_newscate_table cannot be reverted.\n";
        $this->dropTable("news-cate");
        return false;
    

那么如何在 Yii2 中使用 Migration 创建复合主键呢？

【参考方案1】：

最简单的方法

理想情况下，您要为两个表创建联结。您可以使用 Yii 命令行通过一行代码创建迁移：

php yii migrate/create create_junction_table_for_post_and_tag_tables --fields="created_at:bigInteger"

它会生成：

/**
 * Handles the creation for table `post_tag`.
 * Has foreign keys to the tables:
 *
 * - `post`
 * - `tag`
 */
class m160328_041642_create_junction_table_for_post_and_tag_tables extends Migration

    /**
     * @inheritdoc
     */
    public function up()
    
        $this->createTable('post_tag', [
            'post_id' => $this->integer(),
            'tag_id' => $this->integer(),
            'created_at' => $this->dateTime(),
            'PRIMARY KEY(post_id, tag_id)',
        ]);

        // creates index for column `post_id`
        $this->createIndex(
            'idx-post_tag-post_id',
            'post_tag',
            'post_id'
        );

        // add foreign key for table `post`
        $this->addForeignKey(
            'fk-post_tag-post_id',
            'post_tag',
            'post_id',
            'post',
            'id',
            'CASCADE'
        );

        // creates index for column `tag_id`
        $this->createIndex(
            'idx-post_tag-tag_id',
            'post_tag',
            'tag_id'
        );

        // add foreign key for table `tag`
        $this->addForeignKey(
            'fk-post_tag-tag_id',
            'post_tag',
            'tag_id',
            'tag',
            'id',
            'CASCADE'
        );
    

    /**
     * @inheritdoc
     */
    public function down()
    
        // drops foreign key for table `post`
        $this->dropForeignKey(
            'fk-post_tag-post_id',
            'post_tag'
        );

        // drops index for column `post_id`
        $this->dropIndex(
            'idx-post_tag-post_id',
            'post_tag'
        );

        // drops foreign key for table `tag`
        $this->dropForeignKey(
            'fk-post_tag-tag_id',
            'post_tag'
        );

        // drops index for column `tag_id`
        $this->dropIndex(
            'idx-post_tag-tag_id',
            'post_tag'
        );

        $this->dropTable('post_tag');
    

表结构是这样的：

+------------+------------+------+-----+---------+-------+
| Field      | Type       | Null | Key | Default | Extra |
+------------+------------+------+-----+---------+-------+
| post_id    | int(11)    | NO   | PRI | NULL    |       |
| tag_id     | int(11)    | NO   | PRI | NULL    |       |
| created_at | bigint(20) | YES  |     | NULL    |       |
+------------+------------+------+-----+---------+-------+

请查看下面提到的 URL 以供参考：

http://www.yiiframework.com/doc-2.0/guide-db-migrations.html

【参考方案2】：

更新

从 yii 2.06 版开始，您可以使用新的架构生成器：

<?php
use yii\db\Migration;
...
$this->createTable('news-cate', [
    'news-id' => $this->integer()->notNull(),
    'cate-id' => $this->integer()->notNull(),
]);
$this->addPrimaryKey('news-cate_pk', 'news-cate', ['news-id', 'cate-id']);
...
?>

原始答案

建表时不要添加主键，只声明类型：

use yii\db\Schema;

,,,

$this->createTable('news-cate', [
    'news-id' => Schema::TYPE_INTEGER . ' NOT NULL',
    'cate-id' => Schema::TYPE_INTEGER . ' NOT NULL',
]);

之后你可以像这样添加复合主键：

$this->addPrimaryKey('news-cate_pk', 'news-cate', ['news-id', 'cate-id']);

对于多列，addPrimaryKey() 方法中允许使用数组。

这比编写原始 sql 更好。

【讨论】：

这也是创建非整数类型主键的最佳方式。

这是否也会为复合主键创建唯一索引？

【参考方案3】：

试试这个方法

public function safeUp()

   $this->createTable('news-cate', [
        'news-id' =>'int NOT NULL',
        'cate-id' =>'int NOT NULL',
        'PRIMARY KEY (news-id,cate-id)'
      ]);
    $this->addForeignKey("fk_news_cate_nid", "news-cate", "news-id", "news", "id", "RESTRICT", "CASCADE");
    $this->addForeignKey("fk_news_cate_cid", "news-cate", "cate-id", "category", "id", "RESTRICT", "CASCADE");