iPhone: Converting Oracle Timestamp to NSDate or to Unix Timestamp (e.g. double)

Question

Is there a good+easy way to convert an Oracle Timestamp to an NSDate object on the iPhone? I have asked my customer to give me a DB with timestamps as Unix Timestamp (doubles with 0 = start of 1970) but it seems to be a problem for them. Thanks.

Note: You can easily convert a Unix Timestamp to an NSDate with

[NSDate dateWithTimeIntervalSince1970: timestamp]  // timestamp is a "double"

What I need to do is convert the Oracle timestamp to a double, aka Unix Timestamp. The rest is easy.

More info: I need Objective-C code to run on the iPhone using NSStrings that represent dates in Oracle Timestamp format. Another StackOverflow thread suggests using NSDateFormatter, but I don't know what format to use and the initialization method for the formatter suggested in that thread generates a warning for me.

Answer 1

I'm not sure about the converting to an NSDate, but you can convert an Oracle date to a unix timestamp easily. The following SQL snippet will do it:

(my_date - to_date('01/01/1970','DD/MM/YYYY')) * 86400

Answer 2

It looks like my best bet is to use the following:

NSDateFormatter* formatter = [[NSDateFormatter alloc] init];    
[formatter setDateFormat:@"MM/dd/yyyy HH:mm a"];

I'm not sure how much variance there is in Oracle timestamps, so if there is a problem with the above approach, I'd love to know.

Thanks for the other answers. I will leave the question open to invite other approaches.