Question

在将数据添加到具有一对多关系的核心数据模型时遇到一些麻烦。

以下是我的模特：

RecordDate - Relationship: records - One to Many with RecordWorkout.
RecordWorkout - Relationship: recExercises - One to Many With RecordExercise.
RecordExercise - Relationship: sets - One to Many With RecordSet.
RecordSet

RecordDate包含单个字符串变量日期。（不存储重复的日期变量）

RecordWorkout包含单个字符串变量recWorkoutName。（不能存储recWorkoutName的重复变量。）

RecordExercise包含单个字符串变量recExerciseName。（也不能存储recExerciseName的重复变量。

RecordSet包含三个字符串变量（setLog，weight，reps）。（同样，不能为setLog变量存储重复变量。

代码目标：

目标是单击一个按钮（日志按钮），单击“按钮”时，代码需要将屏幕上的值与数据存储中已有的值进行比较，这样就不会存储重复值。

示例：

日期＆gt; workoutName＆gt;运动＆gt; （许多集合例如：set1，set2，set3，set4）

首次点击按钮日期时，会存储workoutName exerciseName和第一组详细信息。在第二次点击时，只存储新的设定数据。

下面是我正在使用的代码，但它似乎没有存储所有设置值，有些集会从数据存储中丢失或只存储第一个集。

setCount = setCount + 1;
NSString *weight = weightTextField.text;
NSString *reps = repsTextField.text;


NSString *setStr = [NSString stringWithFormat:@"%d", (int)setCount];

NSMutableString *log = [NSMutableString stringWithFormat:@"%@ %@%@ %@ %@ %@ %@", @"Set", setStr, @":", weight, @"kg X", reps, @"reps"];
[self.tempLog addObject:log];
[self.myTableView reloadData];
[weightTextField resignFirstResponder];
[repsTextField resignFirstResponder];
//the set is stored in a temporary mutable array (tempLog) just to show in tableview
//i would rather just store it in the actual entity and fetch from there

//Entities are initialised below
NSEntityDescription *recordDateEntity = [NSEntityDescription entityForName:@"RecordDate"
                                                    inManagedObjectContext:self.managedObjectContext];

NSEntityDescription *recordWorkoutEntity = [NSEntityDescription entityForName:@"RecordWorkout"
                                                       inManagedObjectContext:self.managedObjectContext];

NSEntityDescription *recordExerciseEntity = [NSEntityDescription entityForName:@"RecordExercise"
                                                        inManagedObjectContext:self.managedObjectContext];

NSEntityDescription *recordSetEntity = [NSEntityDescription entityForName:@"RecordSet"  inManagedObjectContext:self.managedObjectContext];

//Data is fetched from the existing store to be compared with the data on screen
//This data is stored in mutable arrays (record date, recordworkouts, recordexercises, recordsets)
NSManagedObjectContext *managedObjectContext = [self managedObjectContext];

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:@"RecordDate"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"date == %@", dateLabel.text];
[fetchRequest setPredicate:predicate];
self.recorddates = [[managedObjectContext executeFetchRequest:fetchRequest error:nil] mutableCopy];

NSFetchRequest *fetchRWRequest = [[NSFetchRequest alloc] initWithEntityName:@"RecordWorkout"];
NSPredicate *predicateRW = [NSPredicate predicateWithFormat:@"recWorkoutName == %@", testLabel2.text];
[fetchRWRequest setPredicate:predicateRW];
self.recordworkouts = [[managedObjectContext executeFetchRequest:fetchRWRequest error:nil] mutableCopy];

NSFetchRequest *fetchRERequest = [[NSFetchRequest alloc] initWithEntityName:@"RecordExercise"];
NSPredicate *predicateRE = [NSPredicate predicateWithFormat:@"recExerciseName == %@", exNameLabel.text];
[fetchRERequest setPredicate:predicateRE];
self.recordexercises = [[managedObjectContext executeFetchRequest:fetchRERequest error:nil] mutableCopy];

NSFetchRequest *fetchRSetRequest = [[NSFetchRequest alloc] initWithEntityName:@"RecordSet"];
NSPredicate *predicateRSet = [NSPredicate predicateWithFormat:@"setLog == %@", setStr];
[fetchRSetRequest setPredicate:predicateRSet];
self.recordsets = [[managedObjectContext executeFetchRequest:fetchRSetRequest error:nil] mutableCopy];

if ([self.recorddates count] == 0) {

    NSLog(@"No Dates Imported");

    RecordDate *newRecordDate = (RecordDate *)[[NSManagedObject alloc]
                                               initWithEntity:recordDateEntity
                                               insertIntoManagedObjectContext:self.managedObjectContext];
    newRecordDate.date = dateLabel.text;

    RecordWorkout *newRecordWorkout = (RecordWorkout *)[[NSManagedObject alloc]
                                                        initWithEntity:recordWorkoutEntity
                                                        insertIntoManagedObjectContext:self.managedObjectContext];

    newRecordWorkout.recWorkoutName = testLabel2.text;
    [newRecordDate addRecordsObject:newRecordWorkout];

    RecordExercise *newRecordExercise = (RecordExercise *)[[NSManagedObject alloc] initWithEntity:recordExerciseEntity insertIntoManagedObjectContext:self.managedObjectContext];

    newRecordExercise.recExerciseName = exNameLabel.text;
    [newRecordWorkout addRecExercisesObject:newRecordExercise];



    RecordSet *newRecordSet = (RecordSet *)[[NSManagedObject alloc]
                                            initWithEntity:recordSetEntity
                                            insertIntoManagedObjectContext:self.managedObjectContext];

    newRecordSet.setLog = setStr;
    newRecordSet.weight = weight;
    newRecordSet.reps = reps;
    [newRecordExercise addSetsObject:newRecordSet];

    NSLog(@"Set number one should be added to model: %@", setStr);

} else {

    NSLog(@"Dates Are Imported");

    RecordDate *prevRecordDate = (RecordDate *)[self.recorddates objectAtIndex:0];

    if ([self.recordworkouts count] == 0) {

        RecordWorkout *newRecordWorkout = (RecordWorkout *)[[NSManagedObject alloc]
                                                            initWithEntity:recordWorkoutEntity
                                                            insertIntoManagedObjectContext:self.managedObjectContext];
        newRecordWorkout.recWorkoutName = testLabel2.text;
        [prevRecordDate addRecordsObject:newRecordWorkout];

        RecordExercise *newRecordExercise = (RecordExercise *)[[NSManagedObject alloc] initWithEntity:recordExerciseEntity insertIntoManagedObjectContext:self.managedObjectContext];

        newRecordExercise.recExerciseName = exNameLabel.text;
        [newRecordWorkout addRecExercisesObject:newRecordExercise];

        RecordSet *newRecordSet = (RecordSet *)[[NSManagedObject alloc]
                                                initWithEntity:recordSetEntity
                                                insertIntoManagedObjectContext:self.managedObjectContext];

        newRecordSet.setLog = setStr;
        newRecordSet.weight = weight;
        newRecordSet.reps = reps;
        [newRecordExercise addSetsObject:newRecordSet];

    } else {

        RecordWorkout *prevRecordWorkout = [self.recordworkouts objectAtIndex:0];


        if ([self.recordexercises count] == 0) {

            RecordExercise *newRecordExercise = (RecordExercise *)[[NSManagedObject alloc] initWithEntity:recordExerciseEntity insertIntoManagedObjectContext:self.managedObjectContext];


            newRecordExercise.recExerciseName = exNameLabel.text;
            [prevRecordWorkout addRecExercisesObject:newRecordExercise];

            RecordSet *newRecordSet = (RecordSet *)[[NSManagedObject alloc]
                                                    initWithEntity:recordSetEntity
                                                    insertIntoManagedObjectContext:self.managedObjectContext];

            newRecordSet.setLog = setStr;
            newRecordSet.weight = weight;
            newRecordSet.reps = reps;
            [newRecordExercise addSetsObject:newRecordSet];

        } else {

            RecordExercise *prevRecordExercise = [self.recordexercises objectAtIndex:0];

            if ([self.recordsets count] == 0) {

                RecordSet *newRecordSet = (RecordSet *)[[NSManagedObject alloc]
                                                        initWithEntity:recordSetEntity
                                                        insertIntoManagedObjectContext:self.managedObjectContext];

                newRecordSet.setLog = setStr;
                newRecordSet.weight = weight;
                newRecordSet.reps = reps;
                [prevRecordExercise addSetsObject:newRecordSet];

            } else {

                NSLog(@"Sets Already Imported");
            }
        }
    }

    NSError *errr;
    if (![self.managedObjectContext save:&errr])
    {
        NSLog(@"Error saving context: %@", errr);
    }
}

我觉得在使用更好的组织代码之后我可以实现我的目标。

感谢您提供的任何帮助。

PS。上面的代码在logButtonPressed方法

中

Answer 1

它可以简单得多。

1）对于提取，仅提取日期并让Core Data负责获取其他内容就足够了。效率更高，代码更少。要“获取”相关实体：

NSSet *workouts = date.workouts; 
NSSet *exercises = aWorkout.exercises;
NSSet *sets = anExercise.sets;

2）用于检查项目是否存在，例如日期只是遵循这种模式：

NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Date"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:
       @"%K = %@", attributeName, theDateStringToBeChecked];
request.fetchLimit = 1;
NSArray *dates = [self.managedObjectContext executeFetchRequest:request];
NSManagedObject *objectToUse = dates.count ? dates[0] : [NSEntityDescription 
   insertNewObjectForEntityName:"Date" 
   inManagedObjectContext:self.managedObjectContext];

通过构造一个获取实体字符串，属性字符串和要检查的值的方法，可以大大减少代码。它会有这样的原型：

-(NSManagedObject*)existingOrNewObjectWithEntityName:(NSString*)name
      attribute:(NSString*)attribute value:(NSString*)value;

因为您的对象是NSManagedObject的子类，所以您可以简单地将它们转换为正确的类型。

最后，不要忘记致电[self.managedObjectContext save:&error];来保留您的更改。

将数据添加到一对多核心数据模型

1 个答案: