It depends on what your items are like. Many games will just have a table of item types, and then the character record will list how many items of which types that character has. Only if you have unique items (special unique artifacts, or customizable items) might you want/need separate tables with records for each actual item, with links back to the owner, and perhaps not even then, though there might be reasons to do it that way depending on your game design.
Given the detail you added in the comment here, I'd suggest a table of characters, a table of item types, and then a table of actual items, with a column for the item type id, a column for the owner id (I would use an integer ID not an email string), and then you can add columns to that table if you end up having properties for specific items (for enhancements, damage to the item, special conditions, etc).
There can be a bit of a performance tradeoff in terms of looking the information up in the database, but probably you will write your code so you only look up the info from the database rarely, and keep local copies in memory when you are frequently re-using the information during play.