Mapper feature is separated in another package called
loon-data. It's not production-ready.
Mapper takes care of mapping object to a model which have relationships with other models. It's usually used in map relational database query result to model.
A complex example:
class Comment {
@Property()
public id: number;
@Property()
public postId: number;
@Property()
public name: string;
@Property()
public comment: string;
}
class Tag {
@Property()
public id: number;
}
class Author {
@Property()
public id: number;
@Property()
public username: string;
@Property()
public password: string;
@Property()
public email: string;
@Property()
public bio: string;
@Property('favourite_section')
public favouriteSection: string;
}
class Post {
@Property()
public id: number;
@Property()
public subject: string;
public author: Author;
public comments: Comment[];
public tags: Tag[];
}
class Blog {
@Property()
public id: number;
@Property()
public title: string;
public author: Author;
public posts: Post[];
}
const AuthorMap: AssociationMap = {
property: 'author',
type: Author,
prefix: 'author_'
};
const BlogMap: DataMap = {
type: Blog,
prefix: 'blog_',
associations: [
AuthorMap
],
collections: [
{
property: 'posts',
type: Post,
prefix: 'post_',
associations: [
AuthorMap
],
collections: [
{
property: 'comments',
type: Comment,
prefix: 'comment_'
},
{
property: 'tags',
type: Tag,
prefix: 'tag_'
}
]
}
]
};
/**
* SQL:
* select(
* 'B.id as blog_id',
* 'B.title as blog_title',
* 'B.author_id as blog_author_id',
* 'A.id as author_id',
* 'A.username as author_username',
* 'A.password as author_password',
* 'A.email as author_email',
* 'A.bio as author_bio',
* 'A.favourite_section as author_favourite_section',
* 'P.id as post_id',
* 'P.blog_id as post_blog_id',
* 'P.author_id as post_author_id',
* 'P.created_on as post_created_on',
* 'P.section as post_section',
* 'P.subject as post_subject',
* 'P.draft as post_draft',
* 'P.body as post_body',
* 'C.id as comment_id',
* 'C.post_id as comment_post_id',
* 'C.name as comment_name',
* 'C.comment as comment_text',
* 'T.id as tag_id',
* 'T.name as tag_name'
* )
* .from('blogs1 as B')
* .leftOuterJoin('authors1 as A', 'A.id', 'B.author_id')
* .leftOuterJoin('posts1 as P', 'P.blog_id', 'B.id')
* .leftOuterJoin('comments1 as C', 'C.post_id', 'P.id')
* .leftOuterJoin('posts_tags1 as PT', 'PT.post_id', 'P.id')
* .leftOuterJoin('tags1 as T', 'T.id', 'PT.tag_id')
* .where({'B.id': id})
*
* Tables:
* CREATE TABLE `authors1` (
* `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
* `username` varchar(255) DEFAULT NULL,
* `password` varchar(255) DEFAULT NULL,
* `email` varchar(255) DEFAULT NULL,
* `bio` varchar(255) DEFAULT NULL,
* `favourite_section` varchar(255) DEFAULT NULL,
* PRIMARY KEY (`id`)
* ) ENGINE=InnoDB AUTO_INCREMENT=89 DEFAULT CHARSET=utf8;
*
* CREATE TABLE `blogs1` (
* `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
* `title` varchar(255) DEFAULT NULL,
* `author_id` int(11) DEFAULT NULL,
* PRIMARY KEY (`id`)
* ) ENGINE=InnoDB AUTO_INCREMENT=45 DEFAULT CHARSET=utf8;
* CREATE TABLE `comments1` (
* `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
* `post_id` int(11) DEFAULT NULL,
* `name` varchar(255) DEFAULT NULL,
* `comment` varchar(255) DEFAULT NULL,
* PRIMARY KEY (`id`)
* ) ENGINE=InnoDB AUTO_INCREMENT=133 DEFAULT CHARSET=utf8;
* CREATE TABLE `posts_tags1` (
* `post_id` int(11) DEFAULT NULL,
* `tag_id` int(11) DEFAULT NULL
* ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
* CREATE TABLE `posts1` (
* `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
* `blog_id` int(11) DEFAULT NULL,
* `author_id` int(11) DEFAULT NULL,
* `created_on` varchar(255) DEFAULT NULL,
* `section` varchar(255) DEFAULT NULL,
* `subject` varchar(255) DEFAULT NULL,
* `draft` tinyint(1) DEFAULT NULL,
* `body` varchar(255) DEFAULT NULL,
* PRIMARY KEY (`id`)
* ) ENGINE=InnoDB AUTO_INCREMENT=89 DEFAULT CHARSET=utf8;
* CREATE TABLE `tags1` (
* `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
* `name` varchar(255) DEFAULT NULL,
* PRIMARY KEY (`id`)
* ) ENGINE=InnoDB AUTO_INCREMENT=89 DEFAULT CHARSET=utf8;
* CREATE TABLE `users1` (
* `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
* `username` varchar(255) DEFAULT NULL,
* `hashedPassword` varchar(255) DEFAULT NULL,
* PRIMARY KEY (`id`)
* ) ENGINE=InnoDB AUTO_INCREMENT=41 DEFAULT CHARSET=utf8;
*/
class BlogRepository {
@ResultMapping(BlogMap)
public queryBlog() {
return [
{
"blog_id": 44,
"blog_title": "great blog",
"blog_author_id": 87,
"author_id": 87,
"author_username": "Jack",
"author_password": "password",
"author_email": "jack@gmail.com",
"author_bio": null,
"author_favourite_section": "NO.1",
"post_id": 87,
"post_blog_id": 44,
"post_author_id": 87,
"post_created_on": "2077-07-07",
"post_section": "s1",
"post_subject": "first blog",
"post_draft": 1,
"post_body": "body 1",
"comment_id": 130,
"comment_post_id": 87,
"comment_name": "1",
"comment_text": "c1",
"tag_id": 87,
"tag_name": "great"
},
{
"blog_id": 44,
"blog_title": "great blog",
"blog_author_id": 87,
"author_id": 87,
"author_username": "Jack",
"author_password": "password",
"author_email": "jack@gmail.com",
"author_bio": null,
"author_favourite_section": "NO.1",
"post_id": 87,
"post_blog_id": 44,
"post_author_id": 87,
"post_created_on": "2077-07-07",
"post_section": "s1",
"post_subject": "first blog",
"post_draft": 1,
"post_body": "body 1",
"comment_id": 131,
"comment_post_id": 87,
"comment_name": "2",
"comment_text": "c2",
"tag_id": 87,
"tag_name": "great"
},
{
"blog_id": 44,
"blog_title": "great blog",
"blog_author_id": 87,
"author_id": 87,
"author_username": "Jack",
"author_password": "password",
"author_email": "jack@gmail.com",
"author_bio": null,
"author_favourite_section": "NO.1",
"post_id": 87,
"post_blog_id": 44,
"post_author_id": 87,
"post_created_on": "2077-07-07",
"post_section": "s1",
"post_subject": "first blog",
"post_draft": 1,
"post_body": "body 1",
"comment_id": 132,
"comment_post_id": 87,
"comment_name": "3",
"comment_text": "c3",
"tag_id": 87,
"tag_name": "great"
},
{
"blog_id": 44,
"blog_title": "great blog",
"blog_author_id": 87,
"author_id": 87,
"author_username": "Jack",
"author_password": "password",
"author_email": "jack@gmail.com",
"author_bio": null,
"author_favourite_section": "NO.1",
"post_id": 87,
"post_blog_id": 44,
"post_author_id": 87,
"post_created_on": "2077-07-07",
"post_section": "s1",
"post_subject": "first blog",
"post_draft": 1,
"post_body": "body 1",
"comment_id": 130,
"comment_post_id": 87,
"comment_name": "1",
"comment_text": "c1",
"tag_id": 88,
"tag_name": "cloud"
},
{
"blog_id": 44,
"blog_title": "great blog",
"blog_author_id": 87,
"author_id": 87,
"author_username": "Jack",
"author_password": "password",
"author_email": "jack@gmail.com",
"author_bio": null,
"author_favourite_section": "NO.1",
"post_id": 87,
"post_blog_id": 44,
"post_author_id": 87,
"post_created_on": "2077-07-07",
"post_section": "s1",
"post_subject": "first blog",
"post_draft": 1,
"post_body": "body 1",
"comment_id": 131,
"comment_post_id": 87,
"comment_name": "2",
"comment_text": "c2",
"tag_id": 88,
"tag_name": "cloud"
},
{
"blog_id": 44,
"blog_title": "great blog",
"blog_author_id": 87,
"author_id": 87,
"author_username": "Jack",
"author_password": "password",
"author_email": "jack@gmail.com",
"author_bio": null,
"author_favourite_section": "NO.1",
"post_id": 87,
"post_blog_id": 44,
"post_author_id": 87,
"post_created_on": "2077-07-07",
"post_section": "s1",
"post_subject": "first blog",
"post_draft": 1,
"post_body": "body 1",
"comment_id": 132,
"comment_post_id": 87,
"comment_name": "3",
"comment_text": "c3",
"tag_id": 88,
"tag_name": "cloud"
},
{
"blog_id": 44,
"blog_title": "great blog",
"blog_author_id": 87,
"author_id": 87,
"author_username": "Jack",
"author_password": "password",
"author_email": "jack@gmail.com",
"author_bio": null,
"author_favourite_section": "NO.1",
"post_id": 88,
"post_blog_id": 44,
"post_author_id": 87,
"post_created_on": "2077-07-17",
"post_section": "s2",
"post_subject": "second blog",
"post_draft": 0,
"post_body": "body 2",
"comment_id": null,
"comment_post_id": null,
"comment_name": null,
"comment_text": null,
"tag_id": 87,
"tag_name": "great"
}
];
}
}
const repo = new BlogRepository();
const blog = repo.queryBlog();
blog instanceof Blog # => trueIn this example, Blog have one to many relationship with Post, and have one to one relationship with Author.
Post have one to one relationship with Author, and have one to many relationship with Tag and Comment.
ResultMapping will return a single model result, it accept argument with interface DataMap.
DataMap have one required field is type, which specified the model you want to map.
prefix is for preventing complex data property name conflict.
associations is for the model to one relationship.
It accepts array of AssociationMap, which extends DataMap and have another one required field property.
collections is for the model to many relationship.
It accepts array of CollectionMap, which is the same as AssociationMap.
Currently the DataMap should have one property called id to distinguish the different results.
ResultsMapping is just like ResultMapping, but it returns an array of result.
class Developer {
@Property()
public name: string;
@Property({name: "skillsContent"})
public skills: string[];
}
class PeopleRepository {
@EntityMapping()
public insertDeveloper(developer: Developer) {
return developer; // developer is now an object
}
}The class will automatically convert back to object with @EntityMapping.