I need to store some social ids (facebook/google/twitter user id, facebook place id, ecc..) in my MySQL DB. I found a lot of questions about this here on stackoverflow, but I didn't find a satisfactory answer. For example you can't be sure 100% that facebook id will always be a unsigned bigint, from facebook documentation the facebook id is described as "numeric string". Google id seems one digit bigger than bigint.
I believe that an index on a varchar column is slower than an index on a bigint column, for this reason I thought that using bigint, when possible, would be better than varchar. But I realized that you can store a varchar as a binary with the appropriate attribute.
For this reason I was thinking about use a varchar for all these social ids and (since the ordering is not an issue) store it as binary (attribute=binary), this because I need a fast index on them. what's your thoughts: is this a good and fast solution? Thanks
I use varchar. You are right about the differences, but even more importantly, there is no guarantee that the current type will stay the same. For instance, Facebook changes the size in the past and they mentioned somewhere that they may include chars in it.
An index is an index, if done right, there is no need to worry about its performance. No real difference between an index on numbers or varchar.