Objective-C and MySQL

Question

I\'ve been able to connect to a MySQL database in my app and use the C API which is almost exactly like PHP commands (mysql_real_connect(), mysql_query(), mysql_fetch_array(), e

Answer 1

There's no Apple-supplied Objective-C API for MySQL. There are a few third-party wrappers of the C API, though. Take a look at the MySQL-Cocoa Framework, for example.

Given your familiarity with the PHP and C API, it may be more straightforward for you simply to use the C API. You'll need to handle conversion between objects and C data types, but this isn't much work.

Edit

You're crashing because the row value returned by the mysql API isn't an object, and your format string is telling NSLog to treat it as one. The %@ is a format-string placeholder for an object, not a C data type.

It's not clear what the value is in this case. The context seems to imply that it's image data. If that's the case, you'll likely want to create an NSData object from the blob returned by the query, e.g.:

NSData    *imageData;

imageData = [[ NSData alloc ] initWithBytes: row[ i ] length: lengths[ i ]];
NSLog( @"imageData: %@", imageData );
/* ...create NSImage, CGImage, etc... */
[ imageData release ];

If your result fields are just strings, use NSString's -initWithBytes:length:encoding: method:

NSString    *s;

s = [[ NSString alloc ] initWithBytes: row[ i ] length: lengths[ i ]
                        encoding: NSUTF8StringEncoding ];
NSLog( @"result column %d: %@", i, s );
[ s release ];