Question

In my iOS application, I am parsing an XML from a SOAP based webservice and I am storing it into the SQLITE database. The problem that I am facing it is that, it is very slow. It takes about 18 seconds for about 310 rows of data.

Here is what is a sample of my XML –

<return>
<batteryID>1234</batteryID>
<batteryVersionNum>1</batteryVersionNum>
<conceptCode>abc</conceptCode>
<conceptDescription>abc</conceptDescription>
<effectiveEndTime>2010-11-23</effectiveEndTime>
<effectiveStartTime>2010-11-23</effectiveStartTime>
</return>
<return>
<batteryID>2345</batteryID>
<batteryVersionNum>1</batteryVersionNum>
<conceptCode>bac</conceptCode>
<conceptDescription>bac</conceptDescription>
<effectiveEndTime>2010-11-23</effectiveEndTime>
<effectiveStartTime>2010-11-23</effectiveStartTime>
</return>

I use NSXML parser for parsing the XML. For every return tag() I encounter, I create a new instance of my entity –

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName
  namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName
    attributes:(NSDictionary *)attributeDict
{
    if ([elementName isEqualToString:@"return"])
    {
        // Blank lab panel object
        objLabPanel = [NSEntityDescription insertNewObjectForEntityForName:@"LabPanels" inManagedObjectContext:managedObjectContext];
        mainElement = elementName;
    }
}

Once I encounter a return end element (), I save the object to the database –

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName
  namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {

    if ([elementName isEqualToString:@"return"])
    {
        [objPatient addLabPanelsObject:objLabPanel];

        // Save
        NSError *error = nil;
        BOOL saveObj = FALSE;
        saveObj = [managedObjectContext save:&error];

        if (saveObj == FALSE)
        {
            NSLog (@"Error: %@", error);
        }
    }
    else if ([elementName isEqualToString:@"batteryID"] && [mainElement    isEqualToString:@"return"])
    {
    objLabPanel.labPanelBatteryId = elementValue;
    }
    // getting other values from the xml
    . 
    .
    .
    }

Hence for every return tag I encounter, I do a save to the database and so for my 310 or so records, I would be saving it 310 times. So by doing a [managedObjectContext save:&error]; , I guess that it opens the database, saves the data and closes the database and hence it takes a lot of time. Am I right in thinking this way?

Is there a way I can save all the objLabPanel’s to an array and then do a bulk insert to the database i.e. bulk insert the entire array of objLabPanel’s into the SQLITE database at once?

It would be great if someone could help me out with this.

Answer 1

You should save your changes only after you finished importing all entries. No need to save it after every insert.
Also read Core Data Programming Guide: Efficiently Importing Data