Declared in ETCoreData.h

Overview

NSManagedObjectContext (ETCoreData) is a helper category that provides easier and better helper methods to manage NSManagedObjectContext objects.

Tasks

Other methods

Deletion

Arithmetic methods

Querying

Instance Methods

allObjectsOfType:

Returns all the NSManagedObject objects whose entity name matches the one provided.

- (NSArray *)allObjectsOfType:(NSString *)entityName

Parameters

entityName

The name of the NSManagedObject entities to be queried.

Return Value

A NSArray containing all the NSManagedObject on the local database.

Declared In

ETCoreData.h

countObjectsOfType:withPredicate:

Executes the query with the provided NSPredicate for the NSManagedObject whose entity name matches the NSString entity name provided.

- (int)countObjectsOfType:(NSString *)entityName withPredicate:(NSPredicate *)predicate

Parameters

entityName

The entity name of the NSManagedObject entities to be queried.

predicate

The NSPredicate that will be used to filter the query.

Return Value

The count of NSManagedObject whose entity name matches entityName and fulfills the provided predicate.

Discussion

Internally calls fetchObjectsOfType:withPredicate:andSortDescriptors: in order to fulfill the initial query.

Declared In

ETCoreData.h

deleteObjects:

Iterates throught the list of NSManagedObject provided and calls deleteObject: for each one. Then calls submitChanges;

- (void)deleteObjects:(NSArray *)objects

Parameters

objects

A NSArray of NSManageObject that will be iterated to call -deleteObject: on it.

See Also

Declared In

ETCoreData.h

deleteObjectsOfType:withPredicate:

Calls fetchObjectsOfType:withPredicate:andSortDescriptors: with the provided entity name and NSPredicate; then calls deleteObjects: with the resulting NSArray.

- (void)deleteObjectsOfType:(NSString *)entityName withPredicate:(NSPredicate *)predicate

Parameters

entityName

The entity name of the NSManagedObject entity

predicate

The NSPredicate that will be used to filter the query.

Declared In

ETCoreData.h

fetchObjectsOfType:withPredicate:andSortDescriptors:

Executes the provided NSPredicate on the NSManagedObject whose entity name matches the one provided sorted by the provided NSArray of NSSortDescriptor.

- (NSArray *)fetchObjectsOfType:(NSString *)entityName withPredicate:(NSPredicate *)predicate andSortDescriptors:(NSArray *)sortDescriptors

Parameters

entityName

The name of the NSManagedObject entities to be queried.

predicate

The NSPredicate that will be used to filter the query.

sortDescriptors

A NSArray containing NSSortDescriptor objects that will be used to query the database.

Return Value

A NSArray of NSManagedObject that matches the provided predicate.

Declared In

ETCoreData.h

fetchSingleObject:withPredicate:

Fetches a single object for the NSManagedObject whose entity name matches the one provided and fulfills the provided NSPredicate.

- (id)fetchSingleObject:(NSString *)entity withPredicate:(NSPredicate *)predicate

Parameters

entity

The name of the NSManagedObject entities to be queried.

predicate

The NSPredicate that will be used to filter the query.

Return Value

The first NSManagedObject that matches the provided predicate on a NSManagedObject whose entity name matches the one provided.

Declared In

ETCoreData.h

hasEntityWithId:idColumn:identifier:

Checks if there’s a NSManagedObject in the database whose idColumn matches the provided NSString identifier.

- (BOOL)hasEntityWithId:(NSString *)entityName idColumn:(NSString *)idColumn identifier:(NSString *)identifier

Parameters

entityName

The name of the NSManagedObject entities to be queried.

idColumn

The name of the column to be used to query looking for the provided identifier.

identifier

The NSString object that will be used as the key for searching an NSManagedObject.

Return Value

YES if there’s a NSManagedObject that contains the provided identifier on the selected idColumn, NO otherwise.

Declared In

ETCoreData.h

scalarExpressionValueForColumn:expression:entity:withPredicate:

Executes the NSExpression associated to the provided kPredefinedExpression enum value to the column provided on the NSManagedObject whose entity name matches the one provided that also fulfills the NSPredicate provided.

- (int)scalarExpressionValueForColumn:(NSString *)column expression:(kPredefinedExpression)predefinedExpression entity:(NSString *)entity withPredicate:(NSPredicate *)predicate

Parameters

column

The name of the column to be used as the field to execute the NSExpression.

predefinedExpression

The kPredefiendExpression enum value to be used when building the NExpression,

entity

The name of the NSManagedObject entities to be queried.

predicate

The NSPredicate that will be used to filter the query.

Return Value

The int resulting of executing the NSExpression to the to the column provided on the NSManagedObject with the provided entity name that satisfies the provided NSPredicate.

Discussion

This method internally calls fetchObjectsOfType:withPredicate:andSortDescriptors: to fulfill the provided filtering details.

Declared In

ETCoreData.h

submitChanges

Checks if the current NSManagedObjectContext contains changes; if so tries to save them. If an error is found it calls -logDetailErrors with the NSError obtained from the save: operation.

- (BOOL)submitChanges

See Also

  • [NSError logDetailErrors];

Declared In

ETCoreData.h