A couple months ago a girlfriend caught a domestic assault charge with me as her victim, and she told me was represented by a public defender, who later was assigned to me on the same charge just recently with her as my victim. I believe she got her plea deal on the date of arraignment, and he tells me she represented herself. Is there a larger database or is this something he could click and change? If he was standing next to her for her arraignment and "all arraignments are done by this public defenders office," would that not be the same as him being there for later proceedings, more to the point, in this case as a conflict of interest?

Is this from the same crime ? Or is it two separate crimes ?

She assaulted you and went to court.
At a later time you assaulted her and now you are in court ?

There is court records who was her attorney at the time, no, the attorney can not "click" and change it, it would be in writing, it would be in the court transcripts and it would be in court records.

But if the first case is over, and this is a new case, really no, he can defend you, after defending her in a separate case.

A public defender will not do a lot, they will work out a plea deal with the DA office, they will be sure that your legal rights are not violated. They will look at the evidence and tell you what things look like in court.

If you and her were both charged from the same event, both assaulted each other at same time, then no he can not defend both of you for same crime