如何从grails中的映射表中获取值？

Question

我在 grails 中创建了一个域类，它按照代码中的说明映射到 vehicleList。现在我想获取家庭 id = 1 的车辆列表。我可以使用familyInstance.vehicleList 获取此信息。

但我想知道有没有其他方法可以得到这个。我尝试应用标准，但对于createCriteria 和withCriteria，在我提到property("vehicleList") 的预测中显示错误arrayIndexOutOfBound 错误。应用基本的 MySql 查询，我可以直接从映射表中获取数据，但如果我想使用标准获取这些数据，该怎么做。

class Family {

    String name

    Integer noOfVehicle

    List vehicleList

    static hasMany = [vehicleList: String]

    static constraints = {
    }
}



class FamilyController {

 def edit(Family familyInstance) {

        def fi = familyInstance
        println "familyInstance ::: " + familyInstance

        //Try 1
        def familyCriteria = Family.createCriteria()
        def vehicleList = familyCriteria.list{
            createAlias('vehicleList','vlist')
            projections {
                property('vehicleList')
            }
            eq('id',familyInstance.id)
        }
        println "vehicleList ::: " + vehicleList

        //Try 2
        def vehicleList1 = familyInstance.vehicleList
        println "vehicleList1 ::: " + vehicleList1

        //Try 3
        def vehicleList2 = Family.withCriteria{
            createAlias('vehicleList','vlist')
            projections{
                property('vehicleList')
            }
            eq('id',familyInstance.id)
        }
        println "vehicleList2 ::: ===------>>>>>" + vehicleList2
        respond familyInstance
    }
}

数据库结构：

Error with projections

Answer 1

删除您的 createAlias 声明

Family.createCriteria().list{
    projections {
        property('vehicleList')
    }
    eq('id', familyInstance.id)
}

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