Being Cellfish

Stuff I wished I've found in some blog (and sometimes did)

July, 2008

Change of Address
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  • Being Cellfish

    Be suspicious to DAL frameworks


    I've always been suspicious to SQL queries that are automagically generated by some framework. And when I read this article on lengthy SQL queries it certainly was another gallon of gasoline on the fire. Sure premature optimization is the root of all evil and all that but there is also another important rule in software development; Don't do obviously stupid things. If you want to use a framework for data access, which is very common for productivity reasons, be sure to design your software so it is easy to replace the generic framework with something specific.

    If you on the other hand end up with really large queries when you write the queries your self (I'm a stored procedure guy so I have a hard time even making up what kind of SQL query would end up being that large), but it is obvious what the solution is - Stored procedure.

  • Being Cellfish

    Recursively delete empty directories


    I recently had to find a neat way to remove all empty directories recursively on a Unix machine. In the world of UNIX you can expect to find a way to do things like this pretty easy. When I started to search for a neat way to do it (rather than reading a bunch of MAN-pages) I came across a really funny story on The Old New Thing. Windows users are so used to having to use an application to do simple things like this, they forget about scripting possibilities. Guess that will change with Power shell.

    However this was about how to do this on Unix. Well, this is my solution:

    find $1 -type d | sort -r |
    while read D
      ls -l "$D" | grep -q 'total 0' && rmdir "$D" 2>/dev/null

    That script takes one argument; a directory you want to remove if it and all its sub-directories are empty. Any directories encountered where files exists are preserved.

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