我有一个错误en laravel:语法错误或访问冲突:1075表定义不正确.我该如何解决这个问题

Question

**SQLSTATE[42000]：语法错误或访问冲突：1075表定义不正确；只能有一个auto列，并且必须将其定义为键(SQL:create tableloans(id_loanint unsigned not null auto_increment主键、book_idbigint unsigned not null auto_increment主键、user_idbigint signed not null autom_increment primary key、date_vtodate not null(默认字符集utf8mb4 collate'utf8mb04_unicode_ci'(。如何解决此问题？

**

迁移

public function up()
{
Schema::create('books', function (Blueprint $table) {
$table->increments('id_book');
$table->string('title');
$table->integer('amount');
});
}
public function up()
{
Schema::create('users', function (Blueprint $table) {
$table->increments('id');
$table->string('name');
$table->string('username');
$table->string('password');
$table->string('role');
});
}
public function up()
{
Schema::create('loans', function (Blueprint $table) {
$table->increments('id_loan');
$table->bigIncrements('book_id')->unsigned();
$table->bigIncrements('user_id')->unsigned();
$table->date('date_vto');
$table->foreign('book_id')->references('id_book')->on('books')->onDelete('cascade');
$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
});
}

型号书籍

public function loans(){
return $this->hasMany(Loans::class);
}

模型贷款

public function books()
{
return $this->belongsTo(Books::class, 'book_id', 'id_book');
}
public function users()
{
return $this->belongsTo(Users::class, 'user_id', 'id');
}

模型用户

public function loans(){
return $this->hasMany(Loans::class);
}

Answer 1

这个错误不言自明：

$table->increments('id_loan');
$table->bigIncrements('book_id')->unsigned();
$table->bigIncrements('user_id')->unsigned();

您正在数据库中添加多个自动递增数据类型。您可以使用相同的数据类型，但不递增，对于bigIncrements，它是unsignedBigInteger。

你可以在文件中清楚地看到：

bigIncrements方法创建一个自动递增的未签名BIGINT(主键(等价列

$table->unsignedBigInteger('book_id')->unsigned();
$table->unsignedBigInteger('user_id')->unsigned();

请在迁移中替换，然后重试。