How to sort documents by date with CBLView and CBLQuery?

Mobile Couchbase Lite
1

I have an Order document which contains a customerId, productId, and dateOrdered. I want to fetch customer’s first order of a particular product. Below is my CBLView code:

    NSString *type = OrderModel.type;
    NSString *viewName = [type stringByAppendingString:@"CustomerOrdersView"];
    
    CBLView *view = [self.database viewNamed:viewName];
    
    [view setMapBlock: MAPBLOCK({
        
        if ([doc[@"type"] isEqual:OrderModel.type]
            && [doc[@"isActive"] boolValue] == true
            && doc[@"customerId"] != nil
            && doc[@"productId"] != nil) {
            emit(@[doc[@"customerId"], doc[@"productId"]], nil);
        }
        
    }) version:@"4"];

And below is my query code:

    CBLQuery* query = [[self customerOrdersView] createQuery];
    query.keys = @[@[customerId, productId]];
    query.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"value.dateOrdered" ascending:YES]];
    
    NSError *error = nil;
    CBLQueryEnumerator *result = [query run:&error];

However, when I print the dateOrdered values, the results weren’t sorted by dateOrdered. How do I do this? I’m using couchbase-lite 1.3.1.

2

There is no value.dateOrdered, because you’re emitting nil as the value. Try emitting dateOrdered as the value and sorting by “value”.

3

I’ve updated my code by adding dateOrdered in the emit. This is my new CBLView code:

    NSString *type = OrderModel.type;
    NSString *viewName = [type stringByAppendingString:@"CustomerOrdersView"];
    
    CBLView *view = [self.database viewNamed:viewName];
    
    [view setMapBlock: MAPBLOCK({
        
        if ([doc[@"type"] isEqual:OrderModel.type]
            && [doc[@"isActive"] boolValue] == true
            && doc[@"customerId"] != nil
            && doc[@"productId"] != nil
            && doc[@"dateOrdered"] != nil) {
            emit(@[doc[@"customerId"], doc[@"productId"]], doc[@"dateOrdered"]);
        }
        
    }) version:@"6"];

And my query code:

    CBLQuery* query = [[self view] createQuery];
    query.keys = @[@[customerId, productId]];
    query.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"value.dateOrdered" ascending:YES]];
    
    NSError *error = nil;
    CBLQueryEnumerator *result = [query run:&error];

However, this time the code crashes…

2017-07-12 09:36:13.267 Suites[2080:45219] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<__NSCFString 0x60800065b0c0> valueForUndefinedKey:]: this class is not key value coding-compliant for the key dateOrdered.'
4

I think he means you should use “value” to sort by…not “value.dateOrdered”

5

It worked! Thanks everyone :smile: