好吧，我有以下shemas:varBrandSchema=newSchema({name:{type:String,required:true,index:{unique:true},lowercase:true},logo:{type:ObjectId,ref:'Image'}});varFollowActionSchema=newSchema({'actionDate':{type:Date,'default':Date.now},'brand':{type:ObjectId,ref:'Brand'},'performer':{type:ObjectId,ref:'User'},'