Question

I have a drupal site, and am trying to use php to grab some data from my database. What I need to do is to display, in a user’s profile, how many times they were the first person to review a venue (exactly like Yelp’s “First” tally). I’m looking at two options, and trying to decide which is the better way to approach it.

First Option: The first time a venue is reviewed, save the value of the reviewer’s user ID into a table in the database. This table will be dedicated to storing the UID of the first user to review each venue. Then, use a simple query to display a count in the user’s profile of the number of times their UID appears in this table.

Second Option: Use a set of several more complex queries to display the count in the user’s profile, without storing any extra data in the database. This will rely on several queries which will have to do something along the lines of:

1. Find the ID for each review the user has created
2. Check the ID of the venue contained in each review
3. First review for each venue based on the venue ID stored in the review
4. Get the User ID of the author for the first review
5. Check which, if any, of these Author UIDs match the current user’s UID

I’m assuming that this would involve creating an array of the IDs in step one, and then somehow executing each step for each item in the array. There would also be 3 or 4 different tables involved in the query.

I’m relatively new to writing SQL queries, so I’m wondering if it would be better to perform the set of potentially longer queries, or to take the small database hit and use a much much smaller count query instead. Is there any way to compare the advantages of either, or is it like comparing apples and oranges?

Answer 1

The volume of extra data stored will be negligible; the simplification to the processing will be significant. The data won’t change (the first person to review a venue won’t change), so there is a negligible update burden. Go with the extra data and simpler query.