Question

I have a column A; I want to be able to have A[0] column to contain the latest value, A[1] to contain the most recent and so forth. Is this possible? If not is there an alternative?

Answer 1

I’m not sure if MySQL can store arrays in a column. You might be better off with a password_history table, with this structure:

password_history
----------------
password
user_id
sequence_number
password_history_id

password is, well, the password! user_id is the ID of the user that this record’s password belongs to. sequence_number tells you which password this is. Start with 0 for the first password, and just increase it everytime they change their password. You could also store the date that the password was created, instead of a sequence number, if you like that more. password_history_id is just a key column, but you could also not use this, and make the primary key a combination of the other three (and those combinations should always be unique, anyway).