You definitely don't want to use Da Bi because it either sounds like "big nose" or something else that's really bad. The standard Chinese translation for David is 大ä¼ã Pinyin pronunciation is dà wÄi. The characters mean "big/great". I would highly -- *highly* -- recommend you go with something like this instead of Da Bi.
I suggest u to have this Chinese name "大è¡". The sound is "Tai Wai", which is similar to David. And, this is the official translation of the name David. I just checked in an English-Chinese dictionary.
It sounds strange. I advise you to consult a Chinese friend or a Chinese on Chinese names. I mean, i've seen many Chinese give themselves ridiculous English names. Ever heard of 'Pepper' or 'Silver' as a name? If you go tell Chinese that your name is Da Bi, most likely you'll get some weird stares in return.