I have a table in DB that contains the code for an action in the stock market, date and value of this action to date. I am interested only 5 dates per share. I want a simple structure, with, if we consider a table, an action line. Style a table of 6 columns with the code share, the value today, the value of last month, the value. I immediately thought of a table, but is that what are faster in Java? Then I'll have to easily access the values of a share from its code. So I need some kind of index on the action code, that's why I thought of a Map. I tell myself I can do a Map containing the key code of the action and enhance an array of 5 values of my action: I think it's a problem that is often faced, having to store data from a database in a table or a Map and would like your opinion on my idea Map (key, table).