Ethics: Is it ethical for a professor to conduct research using a student's ideas without giving them credit? I pointed a professor (my major advisor) to a resource (a data set), in an email exchange during the beginning of the semester, he published a paper based on this data set several months later, however I had no idea he was working on the project. He did not notify or mention to me about using the data set.

The email that I sent to him earlier when I pointed out the resource had no reply back, however it did indicate in his response that he did not know about the existence of this data set.

When I had a brief (15 minute) meeting with him, he denied that the data set was my idea and said that it was his research colleagues who he got the data set from. I must mention that this data set is freely available and open to the public (online).

My questions are: Is this professor's behavior ethical? and Would I be able to bring this  as a complaint to a higher person in the department (since I have email evidence that he did not have knowledge of this data set prior to my informing him).

My final question to you all is whether I should stay with this person as a major advisor because I am having trust issues with sharing my ideas. The only problem is that anyone else I might choose as my advisor would result in me completely changing my area of research. Thank you.

Edit: Responding to the commenters, when I met with him in person, I he mentioned a paper which he authored, and when I asked for the citation he refused to give it to me saying, "I'll think about it". While my gut feeling is that I should change advisors, the other people in the department are not involved in my area of interest, and the other person who is conducting research in this field refused to be my advisor. What would you do in this situation?

Edit: Thank you for everyone's responses. Perhaps this was just a misunderstanding on my part.
On more than one occasion, a student has pointed out a resource to me that I am already familiar with. In those situations, I always thank the student but don't always mention that I was familiar with it. I don't lie and say that I hadn't seen it before, but see no reason to bring it up (since doing so might make them feel slightly disappointed). If it is open data which has relevance for their field of study it is quite possible that they were already familiar with it. Perhaps in their e-mail they meant that they were unfamiliar with a certain source that contained the data, even though they were familiar with the data itself from another source (such as, from research colleagues who presumably were aware of the source).

The fact that he published a paper several months later is strong evidence that this is indeed the case. The time frame seems too small for him to have begun the research after your email exchange, found something which was publishable, written the paper, and gotten it through peer review. Obviously I don't know the specifics of the case, but I find it implausible that he was unethical in the way that you claim.

I don't see any reason for you to switch advisors. If you unjustly accused him of dishonesty, the real question is if this advisor would still want to work with you as a student. Unless you have evidence which goes beyond what you have communicated here, an apology might be in order.