unicloud-db查询：未在schema内查询到meetinginfo表内userinfo字段的关联关系

meetinginfo表

{  
    "bsonType": "object",  
    "required": [],  
    "permission": {  
        "read": true,  
        "create": true,  
        "update": false,  
        "delete": false  
    },  
    "properties": {  
        "_id": {  
            "description": "ID，系统自动生成"  
        },  
        "meeting_id": {  

        },  
        "uid": {  
            "bsonType": "string",  
            "foreignKey": "userinfo.uid"  
        },  
        "signed": {  

        }  
    }  
}

userinfo表

{  
    "bsonType": "object",  
    "required": [],  
    "permission": {  
        "read": true,  
        "create": true,  
        "update": false,  
        "delete": false  
    },  
    "properties": {  
        "_id": {  
            "description": "ID，系统自动生成"  
        },  
        "uid": {  
            "bsonType": "string"  
        },  
        "nickname": {  
            "bsonType": "string"  
        },  
        "mobile": {  
            "bsonType": "string"  
        }  
    }  
}

<unicloud-db v-slot:default="{data ,loading, error, option}" collection="meetinginfo,userinfo" :where="p_where" field="userinfo{nickname,mobile},signed">  

this.p_where = "meetinginfo.meeting_id==' " + this.model._id+ " ' "  

报错：未在schema内查询到meetinginfo表内userinfo字段的关联关系"

按照教程写的，看不出哪里错了，请问为啥？