Are spaces and capitals okay

[cmoore67]

system: mySQL PHP

re: data integrity, queries and an indexed field.

In my table I have a field "metro", which notes a customers metro area, e.g. San Francicso, CA. Should I change the value to something different, e.g. ca_san_francisco to avoid using spaces, commas and capital letters? Or, is "San Francisco, CA" just as good as "ca_san_francisco" for queries/searches and data integrity in an indexed field?

Thanks,
Chris