Is this were we get the idea that a President's "Executive Order" trumps Constitutional Laws and rights?

I did not think that a mear President had the authority to set aside any such law as they see fit to disobey? I thought only Congress had the right to establish or repeal laws. Or was I mistaught in my American Governments class so long ago? Isn't a violation of the law and oath of Office to uphold and defend the Constitution an Impeachable offense? You can not uphold the Constitution if you can suspend it or declare any part of it as null and void, You live in a dictatorship if your Government officials have such powers.