The document discusses Core Data, including: - Core Data allows storing data in an SQLite database or archiving to files. - Core Data manages relationships between objects and handles fetching, saving, and deleting from the persistent store. - Core Data handles common tasks like object change merging when multiple contexts are used across threads.

1. Core Data
Плюсы, минусы и подводные камни
1

2. Хранение данных
• SQLite
• Core Data
• Archives and Serializations
• User Defaults System
2

3. 3

4. Core Data или SQLite?
3

5. myFolder newMessage
Core Data
4

6. myFolder newMessage
.message
.folder
Core Data
4

7. myFolder newMessage
.message
.folder
myFolder.message = newMessage;
Core Data
4

8. myFolder newMessage
.message
.folder
myFolder.message = newMessage;
newMessage.folder = myFolder;
Core Data
4

9. .folder = myFolder
.messages
message1
message2
.folder = myFolder
Core Data
5

10. .folder = myFolder
.messages
message1
message2
.folder = myFolder
.folder
Core Data
5

11. .folder = myFolder
.messages
message1
message2
.folder = myFolder
.folder = myFolder
Core Data
5

12. .folder = myFolder
.messages
message1
message2
.folder = myFolder
message3
.folder = myFolder
Core Data
5

13. 1
1
.label = {label1}
.messages = {m1} 2
.label = {label1}
2
3
.messages = {m2, m3}
.label = {label2}
Core Data
6

14. 1
1
.label = {label1}
.messages = {m1, m2} 2
.label = {label1, label2}
2
3
.messages = {m2, m3}
.label = {label2}
Core Data
6

15. Delete Rules
• Nullify
• Cascade
• Deny
7

16. nullify
.folder
.message
Delete Rules
8

17. nullify
.message
Delete Rules
8

18. .message = nil
Delete Rules
8

19. 1
1
.label = {label1}
.messages = {m1, m2} 2
2 .label = {label1, label2}
3
.messages = {m2, m3}
.label = {label2}
Delete Rules
9

20. 1
1
.label = {label1}
.messages = {m1, m2}
2
3
.messages = {m2, m3}
.label = {label2}
Delete Rules
9

21. 1
1
.label = {label1}
.messages = {m1}
2
3
.messages = {m3}
.label = {label2}
Delete Rules
9

22. cascade
Delete Rules
10

23. cascade
Delete Rules
10

24. Delete Rules
10

25. deny
Delete Rules
11

26. deny
Delete Rules
11

27. deny
Delete Rules
11

28. NSManagedObject
Memory Management
12

29. Fault Fault
Memory Management
13

30. Folder Fault
Fault Fault
Memory Management
14

31. Folder Fault
Fault Message
Fault Fault
Memory Management
15

32. Folder Folder
Fault Message Message Message
Attach Attach
Memory Management
16

33. Fault Fault
Fault Fault Fault Fault
Fault Fault
Memory Management
17

34. Object Oriented
18

35. Model Versioning
19

36. NSFetchedResultsController
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return [[self.fetchedResultsController sections] count];
}
- (NSInteger)tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section {
id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
return [sectionInfo numberOfObjects];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = <#Get the cell#>;
NSManagedObject *managedObject = [self.fetchedResultsController objectAtIndexPath:indexPath];
return cell;
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
return [sectionInfo name];
}
- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {
return [self.fetchedResultsController sectionIndexTitles];
}
- (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index {
return [self.fetchedResultsController sectionForSectionIndexTitle:title atIndex:index];
}
Interface
20

37. Подводные камни
21

38. NSSet *messages
Ordered Collections
22

39. 1
NSSet *messages
2
3
Ordered Collections
22

40. 1
NSSet *messages
2
3
NSSet *messages
Ordered Collections
22

41. NSSet *messages
1
2
NSSet *messages
Ordered Collections
22

42. 1
1
2
2
3
Ordered Collections
23

43. 1
1 folder1 1 message1
folder1 2 message2
2
folder1 3 message3
folder2 1 message2
2 folder2 2 message3
3
Ordered Collections
23

44. DELETE FROM links WHERE folder = ‘folder1’ 1
1 folder1 1 message1
folder1 2 message2
2
folder1 3 message3
folder2 1 message2
2 folder2 2 message3
3
Ordered Collections
23

45. 1
1 folder1 1 message1
folder1 2 message2
2
folder1 3 message3
folder2 1 message2
2 folder2 2 message3
3
Ordered Collections
23

46. 1
1
2
folder2 1 message2
2 folder2 2 message3
3
Ordered Collections
23

47. 24

48. UPDATE message SET unread = 0 WHERE folder = ‘folder1’
24

49. 24

50. 24

51. 25

52. 25

53. 26

54. .folder = myFolder;
26

55. myFolder
.folder = myFolder;
26

56. Fault
.folder = myFolder;
26

57. 26

58. 27

59. NSManagedObjectID
.folder = [myFolder objectID];
27

60. 28

61. NSManagedObjectContext *moc = [self managedObjectContext];
28

62. NSManagedObjectContext *moc = [self managedObjectContext];
NSError *error = nil;
MailFolder *folder = (MailFolder *)[moc existingObjectWithID:self.folder
error:&error];
28

63. NSManagedObjectContext *moc = [self managedObjectContext];
NSError *error = nil;
MailFolder *folder = (MailFolder *)[moc existingObjectWithID:self.folder
error:&error];
if (error != nil) {
// TODO: handle error!
}
28

64. NSManagedObjectContext *moc = [self managedObjectContext];
NSError *error = nil;
MailFolder *folder = (MailFolder *)[moc existingObjectWithID:self.folder
error:&error];
if (error != nil) {
// TODO: handle error!
}
if (folder != nil) {
self.navigationItem.title = folder.name;
}
28

65. Core Data
is not
thread-safe
29

66. 30

67. Main Thread
Background Thread
30

68. Main Thread
Background Thread
30

69. Main Thread
Background Thread
30

70. Main Thread
Fetch or Save
Background Thread
31

71. Fetch
Main Thread
Background Thread
31

72. Main Thread
Background Thread
Fetch
31

73. Main Thread
Background Thread
Fetch NSManagedObjectID
NSManagedObjectID
NSManagedObjectID
31

74. NSManagedObjectID
NSManagedObjectID
NSManagedObjectID
Main Thread
Background Thread
Fetch
31

75. NSManagedObjectID
NSManagedObjectID
Main Thread
Background Thread
Fetch
31

76. NSManagedObjectID
Main Thread
Background Thread
Fetch
31

77. Main Thread
Background Thread
Fetch
31

78. Main Thread
Background Thread
32

79. Main Thread
Manager
Background Thread
32

80. Main Thread
[ Manager managedObjectContext]
Background Thread
32

81. moc
Main Thread
[ Manager managedObjectContext]
Background Thread
moc
32

82. moc
Main Thread
Manager
Background Thread
moc
32

83. moc
Main Thread
Manager
Background Thread
moc
32

84. moc
Main Thread
Manager
Background Thread
moc
32

85. moc
Main Thread
[ Manager saveContext]
Background Thread
moc
32

86. moc
Main Thread
[ Manager saveContext]
Background Thread
[moc save]
moc
32

87. moc
Main Thread
[ Manager didSaveManagedObjectContextNotification:notification]
Background Thread
moc
32

88. moc
[moc mergeChangesFromContextDidSaveNotification:notification]
Main Thread
[ Manager didSaveManagedObjectContextNotification:notification]
Background Thread
moc
32

89. moc
[moc mergeChangesFromContextDidSaveNotification:notification]
Main Thread
[ Manager didSaveManagedObjectContextNotification:notification]
Background Thread
moc
32

90. NSFetchedResultsController
33

91. NSFetchedResultsController
• Анимация при
изменении списка
объектов
33

92. NSFetchedResultsController
• Анимация при
изменении списка
объектов
• Данные изменяются
прямо под руками
33

93. 34

94. Tips & Tricks
35

95. Сохраняйтесь чаще
36

96. Сохраняйтесь чаще
{
< блок изменений >;
[context save];
}
{
< блок изменений >;
[context save];
}
36

97. Multiple Errors
37

98. Multiple Errors
NSMutableString *errorMessage = [NSMutableString stringWithCapacity:0];
NSArray* detailedErrors = [[error userInfo] objectForKey:NSDetailedErrorsKey];
if ([detailedErrors count] > 0) {
for (NSError* detailedError in detailedErrors) {
[errorMessage appendFormat:@" DetailedError: %@", [detailedError userInfo]];
[errorMessage appendString:@"n"];
}
}
else {
[errorMessage appendFormat:@" %@", [error userInfo]];
}
NSLog(errorMessage);
37

99. NSFetchRequest
38

100. NSFetchRequest
[fetchRequest setFetchBatchSize:25];
38

101. NSFetchRequest
[fetchRequest setFetchBatchSize:25];
Proxy Array
38

102. NSFetchRequest
[fetchRequest setFetchBatchSize:25];
25 Proxy Array
38

103. NSFetchRequest
[fetchRequest setFetchBatchSize:25];
25 25 25 Proxy Array
38

104. NSFetchRequest
[fetchRequest setFetchBatchSize:25];
25 25 25 Proxy Array
[fetchRequest setReturnsObjectsAsFaults:NO];
38

105. NSFetchRequest
[fetchRequest setFetchBatchSize:25];
25 25 25 Proxy Array
[fetchRequest setReturnsObjectsAsFaults:NO];
[fetchRequest setRelationshipKeyPathsForPrefetching:keyPaths];
38

106. NSFetchRequest
[fetchRequest setResultType:NSManagedObjectIDResultType];
38

107. Порядок аргументов
39

108. Порядок аргументов
[NSPredicate predicateWithFormat:@"(subj like ‘mblt12’) AND (unread = 0)"];
39

109. Порядок аргументов
[NSPredicate predicateWithFormat:@"(subj like ‘mblt12’) AND (unread = 0)"];
[NSPredicate predicateWithFormat:@"(unread = 0) AND (subj like ‘mblt12’)"];
39

110. SQLite Engine
40

111. Core Data is an object-graph management and
persistence framework.
© Apple
Core Data is not a database abstraction layer. It is an
object hierarchy that happens to persist to disk.
© Marcus S. Zarra
41

112. Спасибо!
Алексей Додонов
dodonov@yandex-team.ru
42