Laravel 将 `id` 更改为 `AUTO_INCREMENT`

Question

我有一个persons 表和blogs 表。 我想将persons 表的id 列更改为AUTO_INCREMENT。

但它会引发错误。

人员表

id - integer (not auto_increment)
name - string

博客表

id - integer (auto_increment)
title - string
description - text
created_by - integer (foreign key) 

我创建了一个迁移来更改 id 的 persons 表。

更改用户迁移

Schema::table('persons', function (Blueprint $table) {
            $table->bigIncrements('id')->change();
        });

我抛出一个错误

  Illuminate\Database\QueryException  : SQLSTATE[HY000]: General error: 1833 Cannot change column 'id': used in a foreign key constraint 'blogs_created_by_foreign' of table 'db.blogs' (SQL: ALTER TABLE persons CHANGE id id BIGINT UNSIGNED AUTO_INCREMENT NOT NULL)

当我尝试这种方式时。

    public function up()
    {
        \DB::statement("LOCK TABLES  blogs WRITE, persons WRITE;");
        \DB::statement("ALTER TABLE blogs DROP FOREIGN KEY created_by, MODIFY id INT UNSIGNED;");
        \DB::statement("ALTER TABLE persons MODIFY id INT UNSIGNED AUTO_INCREMENT;");
        \DB::statement("ALTER TABLE blogs ADD CONSTRAINT created_by FOREIGN KEY (id) REFERENCES persons (id); UNLOCK TABLES;");

    }

错误：

SQLSTATE[HY000]: General error: 2014 Cannot execute queries while other unbuffered queries are active.  Consider using PDOStatement::fetchAll().  Alternatively, if your code is only ever going to run against mysql, you may enable query buffering by setting the PDO::MYSQL_ATTR_USE_BUFFERED_QUERY attribute. (SQL: LOCK TABLES  blogs WRITE, persons WRITE;)

Answer 1

禁用外键检查然后启用它

DB::statement('SET FOREIGN_KEY_CHECKS=0;');
        Schema::table('persons', function (Blueprint $table) {
            $table->bigIncrements('id')->change();
        });
        DB::statement('SET FOREIGN_KEY_CHECKS=1;');