It really depends on what you are looking for. If you are at an entry level position then you maybe expected to know little. But its still important to understand basic testing methodologies. You have to know testing basics for sure. So I would say brush up your skills on that. Pick a good testing book and understand what testing is, what are the stages of testing, etc.
As for Domain, Database, programming language – it really depends on the products you will be testing. You could be testing a web application that has maybe no database or the organization you work with may not be doing any automation.
You should read up on some basics like what are the automation tools out there, what does each one do.
If you are worried about interviews you can really tell them what you know and what you dont.
can you give me more specifics like what are you doing currently? Have you been in testing for a year already and are looking to change organization? Are you looking for a testing job and want to know what you should know?