没有表连接的Grails"一对多"关系

Question

我是Grails和GORM的新手,我尝试实现"一对多"关系.我在doc中尝试了这个例子:

class Book {
    String title
}
class Author {
    static hasMany = [books: Book]
    String name 
}

以下是生成的表:

AUTHOR
- Id (PK)
- Name

BOOK
- Id (PK)
- Title

AUTHOR_BOOK
- Author_Books_Id
- Book_Id

我期待的更像是:

AUTHOR
- Id (PK)
- Name

BOOK
- Author_Id (PK)
- Book_Index (PK)
- Title

有没有办法实现这一点(摆脱连接表)？

Answer 1

您应该声明该书属于作者.使用belongsTo,您声明Book表中有外键,该外键保持对Author的id列的引用.像这样:

class Book {
    String title
    static belongsTo = [author: Author]
}

class Author {
    static hasMany = [books: Book]
    String name 
}