Delete Objects from relation

The API removes specific objects from a relationship with their parent.

Custom Class ApproachDictionary/Map Approach

Objective-CSwift

- (void)deleteRelationWithColumnName:(NSString * _Nonnull)columnName parentObjectId:(NSString * _Nonnull)parentObjectId childrenObjectIds:(NSArray<NSString *> * _Nonnull)childrenObjectIds responseHandler:^(NSNumber * _Nonnull)responseHandler errorHandler:^(Fault * _Nonnull)errorHandler;

func deleteRelation(columnName: String, parentObjectId: String, childrenObjectIds: [String], responseHandler: ((NSNumber) -> Void)!, errorHandler: ((Fault) -> Void)!)

Objective-CSwift

- (void)deleteRelationWithColumnName:(NSString * _Nonnull)columnName parentObjectId:(NSString * _Nonnull)parentObjectId childrenObjectIds:(NSArray<NSString *> * _Nonnull)childrenObjectIds responseHandler:^(NSNumber * _Nonnull)responseHandler errorHandler:^(Fault * _Nonnull)errorHandler;

func deleteRelation(columnName: String, parentObjectId: String, childrenObjectIds: [String], responseHandler: ((NSNumber) -> Void)!, errorHandler: ((Fault) -> Void)!)

where:

Argument	Description
parentObjectId	Must be objectId of the object which contains specified related child objects.
columnName	Name of the column identifying the relation. Relationship between the specified objects from the children collection will be deleted for the column in the table containing parentObjectId.
childrenObjectIds	A collection of child objectId values for which the relationship with parentObjectId will be deleted.

Return Value

Number of child objects for which the relationship has been deleted.

Example

The example below deletes a relation between a Person object and its children (the relation column is address). The child objects are referenced explicitly in the API call.

Custom Class ApproachDictionary/Map Approach

Objective-CSwift

DataStoreFactory *dataStore = [Backendless.shared.data of:[Person class]];
[dataStore deleteRelationWithColumnName:@"address" parentObjectId:@"XXXXX" childrenObjectIds:@[@"YYYYY"] responseHandler:^(NSNumber *relations) {
    NSLog(@"Relation has been removed");
} errorHandler:^(Fault *fault) {
    NSLog(@"Error: %@", fault.message);
}];

let dataStore = Backendless.shared.data.of(Person.self)
dataStore.deleteRelation(columnName: "address", parentObjectId: "XXXXX", childrenObjectIds: ["YYYYY"], responseHandler: { relations in
    print("Relation has been removed")
}, errorHandler: { fault in
    print("Error: \(fault.message ?? "")")
})

Objective-CSwift

MapDrivenDataStore *dataStore = [Backendless.shared.data ofTable:@"Person"];
[dataStore deleteRelationWithColumnName:@"address" parentObjectId:@"XXXXX" childrenObjectIds:@[@"YYYYY"] responseHandler:^(NSNumber *relations) {
    NSLog(@"Relation has been removed");
} errorHandler:^(Fault *fault) {
    NSLog(@"Error: %@", fault.message);
}];

let dataStore = Backendless.shared.data.ofTable("Person")
dataStore.deleteRelation(columnName: "address", parentObjectId: "XXXXX", childrenObjectIds: ["YYYYY"], responseHandler: { relations in
    print("Relation has been removed")
}, errorHandler: { fault in
    print("Error: \(fault.message ?? "")")
})

Codeless Reference

where:

Argument	Description
table name	Name of the table where which contains the parent object as identified by parent object.
parent object	Id of the object for which the relation will be deleted.
relation name	Name of the column which identifies the relation within the parent table (identified as table name).
children	Represents a list containing unique identifiers(objectIds) of the children objects relations that must be deleted from the data table.
return result	When this box is checked, the operation returns the number of removed child objects relations.

Returns the number of removed child objects relations.

Consider the first object with one-to-many relations(skills column) in the parent data table called employees:

By clicking the record (1:N Relations) in the skills column of the parent data table presented above, you get redirected to the child data table called uniqueSkills, where you can see the related children objects:

Suppose you want to remove two relations. The following example demonstrates the removal of the Objective-C and Javascript relations from the parent object:

The objectId values for each relation are:

1. Objective-C: "4E205196-59B0-45A6-BACB-303A66BEFF22"

2. Javascript: "D08FA6A7-4534-4B43-AF06-BC4CBFE54C60"

After the operation runs, the Objective-C and Javascript relations get deleted.