opening databases

Is it against the rules to use opening databases? I know that engines are out and I'm pretty sure that endgame databases are out too, but I don't know about opening databases.

Originally posted by BrianWigg
Is it against the rules to use opening databases? I know that engines are out and I'm pretty sure that endgame databases are out too, but I don't know about opening databases.

I found the answer near the bottom of the following thread:

[threadid]Using a board to think about moves: is this OK?[/threadid]

According to the rules you can use history of previous games so that includes opening databases.