2.1 关联对象

基于动态实体

Java

BookTable table = BookTable.$;

List<Book> books = sqlClient
    .createQuery(table)
    .where(table.name().eq("Learning GraphQL"))
    .orderBy(table.edition().desc())
    .select(
        table.fetch(
            BookFetcher.$
                .allScalarFields()
                .authors(
                    AuthorFetcher.$
                        .allScalarFields()
                )
        )
    )
    .execute();

Kotlin

val books = sqlClient
    .createQuery(Book::class) {
        where(table.name  eq "Learning GraphQL")
        orderBy(table.edition.desc())
        select(
            table.fetchBy {
                allScalarFields()
                authors {
                    allScalarFields()
                }
            }
        )
    }
    .execute()

得到的结果为

[
    {
        "id":3,
        "name":"Learning GraphQL",
        "edition":3,
        "price":51,
        "authors":[
            {
                "id":2,
                "firstName":"Alex",
                "lastName":"Banks",
                "gender":"MALE"
            },
            {
                "id":1,
                "firstName":"Eve",
                "lastName":"Procello",
                "gender":"FEMALE"
            }
        ]
    },
    {
        "id":2,
        "name":"Learning GraphQL",
        "edition":2,
        "price":55,
        "authors":[
            {
                "id":2,
                "firstName":"Alex",
                "lastName":"Banks",
                "gender":"MALE"
            },
            {
                "id":1,
                "firstName":"Eve",
                "lastName":"Procello",
                "gender":"FEMALE"
            }
        ]
    },
    {
        "id":1,
        "name":"Learning GraphQL",
        "edition":1,
        "price":50,
        "authors":[
            {
                "id":2,
                "firstName":"Alex",
                "lastName":"Banks",
                "gender":"MALE"
            },
            {
                "id":1,
                "firstName":"Eve",
                "lastName":"Procello",
                "gender":"FEMALE"
            }
        ]
    }
]

查询静态DTO

在src/main/dto文件夹下新建任何一个扩展名为dto的文件，编辑代码如下

export com.yourcompany.yourproject.model.Book
    -> package com.yourcompany.yourproject.model.dto

BookView {
    #allScalars(this)
    authors {
        #allScalars(this)
    }
}

编译项目，生成Java/Kotlin类型BookView

Java

BookTable table = BookTable.$;

List<BookView> books = sqlClient
    .createQuery(table)
    .where(table.name().eq("Learning GraphQL"))
    .orderBy(table.edition().desc())
    .select(
        table.fetch(BookView.class)
    )
    .execute();

Kotlin

val books = sqlClient
    .createQuery(Book::class) {
        where(table.name  eq "Learning GraphQL")
        orderBy(table.edition.desc())
        select(
            table.fetch(BookView::class)
        )
    }
    .execute()

得到如下结果

[
    BookView(
        id=3, 
        name=Learning GraphQL, 
        edition=3, 
        price=51.00, 
        authors=[
            BookView.TargetOf_authors(
                id=2, 
                firstName=Alex, 
                lastName=Banks, 
                gender=MALE
            ), 
            BookView.TargetOf_authors(
                id=1, 
                firstName=Eve, 
                lastName=Procello, 
                gender=FEMALE
            )
        ]
    ), 
    BookView(
        id=2, 
        name=Learning GraphQL, 
        edition=2, 
        price=55.00, 
        authors=[
            BookView.TargetOf_authors(
                id=2, 
                firstName=Alex, 
                lastName=Banks, 
                gender=MALE
            ), 
            BookView.TargetOf_authors(
                id=1, 
                firstName=Eve, 
                lastName=Procello, 
                gender=FEMALE
            )
        ]
    ), 
    BookView(
        id=1, 
        name=Learning GraphQL, 
        edition=1, 
        price=50.00, 
        authors=[
            BookView.TargetOf_authors(
                id=2, 
                firstName=Alex, 
                lastName=Banks, 
                gender=MALE
            ), 
            BookView.TargetOf_authors(
                id=1, 
                firstName=Eve, 
                lastName=Procello, 
                gender=FEMALE
            )
        ]
    )
]