Laravel - 多个主键

Question

我是Laravel框架的新手,我也尝试用2个外键创建表,我希望它们成为这个表中的主要表.但是当我写php artisan migrate时我有一个错误

SQLSTATE [42000]:语法错误或访问冲突:1068
定义了多个doc_tag主键(SQL:alter table add primary key doc_tag_id_tag_primar
y(id_tag)

Schema::create('doc_tag', function(Blueprint $table)
{
    $table->integer('id_doc')->unsigned();
    $table->primary('id_doc');
    $table->foreign('id_doc')
                ->references('id')
                ->on('doc');
    $table->integer('id_tag')->unsigned();
    $table->primary('id_tag');
    $table->foreign('id_tag')
                ->references('id')
                ->on('tag');
});

我知道SQL代码是:(但我真的不知道如何在Laravel中翻译这个SQL代码)

CREATE TABLE IF NOT EXISTS `Doc_project`.`document_has_Tags` (
  `document_id_document` INT NOT NULL,
  `Tags_id_Tag` INT NOT NULL,
  PRIMARY KEY (`document_id_document`, `Tags_id_Tag`),
  INDEX `fk_document_has_Tags_Tags1_idx` (`Tags_id_Tag` ASC),
  INDEX `fk_document_has_Tags_document1_idx` (`document_id_document` ASC),
  CONSTRAINT `fk_document_has_Tags_document1`
    FOREIGN KEY (`document_id_document`)
    REFERENCES `Doc_project`.`document` (`id_document`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `fk_document_has_Tags_Tags1`
    FOREIGN KEY (`Tags_id_Tag`)
    REFERENCES `Doc_project`.`Tags` (`id_Tag`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)

这是一个N:N的关系

有人有想法吗？

Answer 1

Eloquent不支持多个主键,但如果您仍然需要它,请将数组发送到您的主键primary(...).

所以在你的情况下:

Schema::create('doc_tag', function(Blueprint $table)
{
    $table->integer('id_doc')->unsigned();
    $table->integer('id_tag')->unsigned();

    $table->primary(['id_tag', 'id_doc']);

    $table->foreign('id_doc')
                ->references('id')
                ->on('doc');    
    $table->foreign('id_tag')
                ->references('id')
                ->on('tag');
});