I haven't don't much in the way or designing a high traffic, production database, but now I find myself in a project where I need to do just that. I have the need to store multiple values per user for several fields. For example, one field is education history in which the user can store as many education records as they'd like. My question is, would it be better to store these values in a separate table that I can join? I saw another method that stored all the values in a single text field for each user record and simple stored the information to parse the data out. This would avoid me from doing 4 or 5 joins on each select, but I didn't know if there was a downside to it. Thanks in advance! Feel free to ask for more information if any of my description is confusing.

the downside is that you cannot search it without doing a table scan, and that doesn't scale (the query gets slower and slower the more rows there are)

every one-to-many relationship should gets its own separate table

Thanks for the feedback! I did not think about searching, but that does make perfect sense. I appreciate the time you took to respond. Thanks again.