It really depends what you are trying to do so your question is a little difficult to answer. There is no 'memory' list object as you would have in modern programming languages but there are a couple of options available to you, again depending on what you are trying to do.
v7 had the option to read an indexed value from a memo variable like: myMemo[0].... and you could either populate the memo through concatenation or from a select statement. It's a while since I used v7 and I can't remember whether the delimeter was tab or line feed.
If you're looking to save DB overhead I'm not sure this helps you because you still have a read of a memo variable which is going to incurr more overhead than a row read. If this is on a folder row then this will be opened on each folder access.
If you have a many to one relationship that you're trying to resolve you could consider using an external table which gives you the advantage of only accessing the data when you need it.
Hope this helps,
Paul
