escape or escape_str

[eluser]berkan[/eluser]
Hello.

I looked in database library files and found the function escape. As i understand escape function uses escape_str with some extras. It adds single quotes to the string and tests the null, boolean variables.

I couldn't find where the escape_str function is.

What is difference between them.?

Escape function adds single quotes to the string.I don't want it to do that. What is the benefit of adding quotes.?

What do you recommend.?
Thanks for giving time.