If the piece of information is always at a given offset, you could use "string range"; if the string is a character-delimited list, you could use "split" to convert it to a tcl-list which then is suitable for commands such as lindex, lrange, and so forth. A third option would be to use regular expressions to use pattern-search to retrieve the value.
Once you've retreaved the piece of information, how you store it in your database would be a matter on what kind of data-storage you use, how you interface with it (any modules/plugins?), etc.