CODEWITHSUNDEEP
iosobjective-ciphonecore-data
Dipen Chudasama
Dipen Chudasama

Reputation: 3093

How to change records order in coredata?

I have some records in core data, its contain name,fulsome,email,image etc.. I was showing this data in collection view, In there I was providing drag-drop/move cell functionality. Now How to Update reordered/rearrange data in core data? please help.

Upvotes: 0

Views: 716

Answers (1)

Francesco
Francesco

Reputation: 1848

CoreData does not have any ordering.

What you have to do is to order the data you fetch. For example if you use a NSFetchRequest you can add an array of NSSortDescriptors which specify the sort ordering of the fetched data

So, for example:

NSFetchRequest *request = ....
request.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES]];

EDIT: after the comment: If the ordering must be persisted to the CoreData store, the only way I see is to add in your model an integer attribute. By default you can leave it at -1, i.e., no order. When you perform the drag and drop in the UI you can then save the index to the attribute and persist it in the store.

Your fetch request can become something like

 request.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"order" ascending:YES], [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES]];

In this way in case of equal ordering (-1) the name will be taken into account, otherwise the index have priority.

Upvotes: 3

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