CS346 - Spring 2011
Database System Implementation

Project FAQ

Modifying previous components

It's very common to make changes to earlier components after you've submitted them. You're welcome to do so as long as you don't change the portions of the interfaces we specified. You may also modify the PF component if you like, as long as you don't modify how I/O statistics are kept. If you do make changes, please turn in the new files with your next submitted component, so we always have the latest files for your project.

String-valued attributes and string comparisons

When a RedBase attribute value is specified as a character string of length n, then it contains n valid characters, even if some of them are the null termination character "\0". For example, suppose we have an attribute that is a character string of length 8. Strings "hello\0\0\0" and "hello\01\0" are both 8-character strings, and "hello\0\0\0 < hello\01\0" should evaluate to true (even though they look the same when printed).

When comparing strings of different lengths, the easiest approach is to make both strings the same length by padding the shorter one with "\0" characters to match the length of the longer one. For example, to compare "hello" with "helloworld" you can pad "hello" to "hello\0\0\0\0\0" then check "hello\0\0\0\0\0 < helloworld".