ios - coredata relationship is set nil automatically -


i have 2 entities. (deal, customer) deal , customer have 1:1 relationship. deal has customer, , customer has deal.

first, made customer object named "john". second, made deal object , set customer "john" (#1 deal) third, made deal object , set customer "john" (#2 deal)

at time, found problem. #1 deal's customer set nil automatically, , #2 deal's customer "john".

how can solve that?

ps1. got data web server json deals = [id: .., ..., customer: { ... }]

ps2. update objects whenever receive data server.

+ (deal *)dealwithdealsdictionary:(nsdictionary *)dic inmanagedobjectcontext:(nsmanagedobjectcontext *)context {     deal *deal = nil;      nsfetchrequest *request = [nsfetchrequest fetchrequestwithentityname:@"deal"];     request.predicate = [nspredicate predicatewithformat:@"deal_id = %@", [dic[@"id"] description]];      // execute fetch      nserror *error = nil;     nsarray *matches = [context executefetchrequest:request error:&error];      // check happened in fetch      if (!matches || ([matches count] > 1)) {  // nil means fetch failed; more 1 impossible (unique!)         deal = [matches lastobject];         // handle error     } else if (![matches count]) {         deal = [nsentitydescription insertnewobjectforentityforname:@"deal" inmanagedobjectcontext:context];     } else {         deal = [matches lastobject];     }      deal.deal_id = [dic[@"id"] description];     deal.deal_status = [dic[@"deal_status"] description];     deal.deal_stage = [dic[@"deal_stage"] description];     deal.deal_desc = [dic[@"deal_desc"] description];     deal.localized_deal_status = [dic[@"localized_deal_status"] description];     deal.localized_deal_stage = [dic[@"localized_deal_stage"] description];      if (dic[@"customer"]) {         [context performblock:^{             deal.customer = [customer customerwithdictionary:dic[@"customer"] inmanagedobjectcontext:context];         }];     }      return deal; }

you don't have 1:1 relationship:it 1:n

2 deals have same customer, 1 customer has n deals.

coredata wanted keep 1:1 constraints 1 deal has 1 unique customer , vice versa.

change one-to-many


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