"... same problem - I don't have a problem remembering songs, but I do have a problem remembering which songs I can remember ..."
Yes, I know.
Just forget databases. The best database - unless you have to deal with millions of songs - is still a text file. Simple reason: In a text file you can search for anything you ever entered. But with a database you have to enter the data knowing what you want to be able to ever search for. And even worse: It works 'best' if you know everything you'll ever want to search for and even everything you'll ever want to enter BEFORE you set up the database itself. And it's hard to remember what you once thought you would want to know when you want to know something you can't remember.
'My way' (fnarr fnarr): Enter the title of each song that comes to your mind into a separate new line of a text file. If you want to add additional data, separate these e.g. with TAB or some other unusual character. From time to time load this text file into e.g. Excel with some option 'separated by e.g. TAB' and then sort the lines. Duplicate entries will then be joined in adjacent lines, and you can easily delete everything that's duplicate while copying everything you want to keep into the line that you keep. The save the result again to a text file with the option 'Separated by ... (whatever)".
Understood? It sounds complicated but it isn't. The advantage is that you only have to UNDERSTAND ONCE and you'll always KNOW HOW. No need to remember something or even know something in advance. The only thing to remember is to DO IT SOMETIMES. Difficult enough if your mind is normally filled with your job or your children or your love or ... or ...