Grails GORM:如何创建复合主键并将其用于表关系？

Question

我有两个表,其中一个(遗留表:A)有两个字段应该作为复合外键,另一个(新表:B)应该使用复合主键作为each row:A has one row:B关系.如何根据GORM描述这些表格？

到目前为止,我已经能够创建一个反映旧表的域类:A

class A {

    ...
    //composite foreign key to link B class
    String className;
    String eventName;

    B b; //instance of B to be related

    static mapping = {
        table 'a_table';            
        id column: 'id';
        className column: 'class_name';
        eventName column: 'event_name';
        //b: ???
    }
}

哪个有效,但我无法创造new class:B和关系.

我试图将B声明为:

class B implements Serializable{

    static auditable = true;

    String name;
    String className;
    String eventName;

    static mapping = {
        //supposed to make a composite PK
        id composite:[className, eventName] 
    }
}

但这不会用a编译
ERROR context.GrailsContextLoader - Error executing bootstraps: Error evaluating ORM mappings block for domain [com.package.B]: No such property: eventName for class: org.codehaus.groovy.grails.orm.hibernate.cfg.HibernateMappingBuilder

我想要的是:

static mapping = {
    ...
    b composite: [b.className:className, b.eventName:eventName]
    //or whatever is the right way for this to be done.
}

为A类让GORM处理这种关系.

Answer 1

您是否尝试使用属性名称而不是使用属性值？

class B implements Serializable{
    String name;
    String className;
    String eventName;

    static mapping = {
        //supposed to make a composite PK
        id composite:['className', 'eventName'] 
    }
}

并在A中映射:

class A {
    static hasMany = [ b : B ]
}

无需拥有className或eventName进入A