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POfetchedResultsController quantity and frequency of object fetching
 

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    <p>I am using a FetchedResultsController to fetch the data for my UITableView. The data is created via actions performed on another tab (so my table may have 5 items but if I switched tabs and go back to my table, it may have more than 5 items that it should display). My table can potentially contain many rows. Right now I am using [myFetchedResultsController performFetch] in my viewDidLoad.It appears that when I create data in my other tab, when I switch back to my table tab, that new data is put into my table automatically without me perfomring [myFetchedResultsController performFetch] again. Here are my questions:</p> <p>1) Does a fetchedResultsController automatically monitor the manajedObjectContext for changes and fetches the new objects if they come into existence? (This appears to be what is happening but I just want to make sure. Perhaps I have some code that is helping me do this that I forgot I put in somewhere)</p> <p>2) Does the fetch performed by [myFetchedResultsController performFetch] fetch all of the objects at that time, or does it fetch only what it can fit in the view of the table and it fetches the rest later as it needs it (as you scroll in the table)? I ask because since my table can potentially have a lot of rows, it seems inefficient to fetch all the data at once if only ~12 of them will be displayed on the table at once. </p> <p>EDIT: I just realized that in my FetchedResultsController delegate methods, I have <code>- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller { [self.tableView reloadData]; }</code></p> <p>Am I correct in saying that a fetchedResultsController monitors for change, but will not apply it to the table unless the table is reloaded as I have done? If so, then I have another question about UITableView. Does reloading the table only reload the rows in view and then the other rows are updated as you scroll? Again I ask because if my data is very large, it seems inefficient to reload the entire table if it will reload all rows at once.</p>
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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

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