两个表之间的关系：在两个表之间建立关系

Question

I have two tables as post and gallery , and i have made a relationship gallery to post table. My requirement is, When user upload content it store in the post table(content field) , If user upload the images are video i want to store the images/video name in, gallery table and the gallery id refers to the post table. I dont know how to do it. please any one help me?

post table:

CREATE TABLE IF NOT EXISTS `post` (
`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`user_id` bigint(20) unsigned NOT NULL,
`gallery_id` bigint(20) unsigned NOT NULL,

`content` longtext,
`photo` varchar(128) DEFAULT NULL,
`video` varchar(128) DEFAULT NULL,

`created` timestamp NULL DEFAULT NULL,
`updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
KEY `fk_forum_post_user` (`user_id`),
KEY `fk_forum_post_gallery` (`gallery_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=10 ;

ALTER TABLE `post`
ADD CONSTRAINT `fk_post_gallery` FOREIGN KEY (`gallery_id`) REFERENCES `gallery`    (`id`) ON DELETE CASCADE ON UPDATE CASCADE,

gallery table

CREATE TABLE IF NOT EXISTS `gallery` (
`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`user_id` bigint(20) unsigned NOT NULL,
`type` int(11) NOT NULL DEFAULT '1' COMMENT '1- Photo, 2-Video, 3-Documents, 4-Unknown',


`profile_picture` varchar(50) DEFAULT NULL,
`forum_image` varchar(200) DEFAULT NULL,
`forum_video` varchar(200) DEFAULT NULL,
`forum_video_link` varchar(200) DEFAULT NULL,

`created` timestamp NULL DEFAULT NULL,
`updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
KEY `fk_gallery_user` (`user_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=60 ;

is any other idea is to do or how can i move forward?

Answer 1

There are a lot of ways you can perform this tasks. you can perform logic on code level as well as on database level. however here is a quick answer . hope this could help you

• First Remove the column ( gallery_id ) as it is possible that user may have more than one images or video for single post or user may not want to upload any image / video in this case your gallery id would be null.
• In this case your Pk would be only postId
• your gallery table is fine
• Make a third table name PostGalleryRealation
• make 2 column in this table PostId as fk from post table and galleryid as fk from gallery table.
• this is basically for one to many relation as one post may have more than one gallery
• insert the post id and gallery id in PostGalleryRealation table
• Finally you can write this query to fetch the result for you.

I did not test the query, so it's just a basic idea

 Select p.id, p.content, p.created, g.type, g.profilepicture, g.forum_image 
   from post p, gallery g, postgalleryrelation pgr 
  where p.id = pgr.postid 
    and g.id = pgr.galleryid
    and p.id = 1

It's just an idea. You can do much better.

Answer 2

YII have relation option while creating CRUD using gii . For that, you have to create tables with foreign key relationship. So YII will automatically create the relation in coding level. You have to choose the option Build Relation while creating model for both tables.

Check the Yii relation tutorials for more information