Core Data to-one/to-many relationship setting error?
Core Data to-one/to-many relationship setting error?
- Subject: Core Data to-one/to-many relationship setting error?
- From: Chataka <email@hidden>
- Date: Sun, 24 Feb 2008 19:39:39 +0900
Hello,
I have a trouble with my non-document-based Core Data application and
hope some advice.
My app has a "Transaction" entity and it has a mainTransaction and a
subTransactions
relationships which are set inverse each other.
mainTransaction to subTransactions is a to-many relationship, while
subTransactions to mainTransaction is a to-one relationship.
I have a method to create a main transaction and sub-transactions
like below.
- (void) createAndSetMainTransaction: (NSArray *) myDataArray //
array of myData
{
MyDataType * myData; // contains transaction attribute data to be
filled in transactionMO
NSManagedObject * firstTransactionMO = nil; // a transactionMO which
will be created first
for ( myData in myDataArray )
{
NSManagedObject * transactionMO = [self
createATransactionMOAndFillMyData: myData];
if ( firstTransactionMO == nil )
{
firstTransactionMO = transactionMO;
}
else
{
[transactionMO setValue: firstTransactionMO forKey:
@"mainTransaction"]; // problematic line
// setting the first transactionMO as the mainTransaction for all
the
// rest of the transactionMOs created within this method
}
}
}
-----
This method works and transactions created here are displayed in an
NSTableView
through NSArrayController and Cocoa Bindings, exactly as I expected.
But once I save the data to a file (with NSSQLiteStoreType) and start
the app again,
the app crashes when the app tries to display the data in the
NSTableView.
If I commented out the "problematic line", the app doesn't crash and
everything
seems fine except the subTransactions don't have the mainTransaction.
I don't figure out what is wrong with the problematic line and hope some
advice to fix this problem.
Thank you.
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