Question

My experience with MySQL is very basic. The simple stuff is easy enough, but I ran into something that is going to require a little more knowledge. I have a need for a table that stores a small list of words. The number of words stored could be anywhere between 1 to 15. Later, I plan on searching through the table by these words. I have thought about a few different methods:

A.) I could create the database with 15 fields, and just fill the fields with null values whenever the data is smaller than 15. I don’t really like this. It seems really inefficient.

B.) Another option is to use just a single field, and store the data as a comma separated list. Whenever I come back to search, I would just run a regular expression on the field. Again, this seems really inefficient.

I would hope there is a good alternative to those two options. Any advice would be very appreciated.

-Thanks

Answer 1

C) use a normal form; use multiple rows with appropriate keys. an example:

mysql> SELECT * FROM blah; +----+-----+-----------+ | K  | grp | name      | +----+-----+-----------+ |  1 |   1 | foo       | |  2 |   1 | bar       | |  3 |   2 | hydrogen  | |  4 |   4 | dasher    | |  5 |   2 | helium    | |  6 |   2 | lithium   | |  7 |   4 | dancer    | |  8 |   3 | winken    | |  9 |   4 | prancer   | | 10 |   2 | beryllium | | 11 |   1 | baz       | | 12 |   3 | blinken   | | 13 |   4 | vixen     | | 14 |   1 | quux      | | 15 |   4 | comet     | | 16 |   2 | boron     | | 17 |   4 | cupid     | | 18 |   4 | donner    | | 19 |   4 | blitzen   | | 20 |   3 | nod       | | 21 |   4 | rudolph   | +----+-----+-----------+ 21 rows in set (0.00 sec) 

This is the table I posted in this other question about group_concat. You’ll note that there is a unique key K for every row. There is another key grp which represents each category. The remaining field represents a category member, and there can be variable numbers of these per category.