NYCPHP Meetup

[David Krings]

Adrian Noland wrote:
  > When it comes to choosing which columns to index, you want to pick
> something with a high cardinality, or, for lack of a better term, 
> "uniqueablity". Gender wont have a high cardinality because there are 
> only 2 choices for many records. Last name on your personal family 
> address book will have a low cardinality because of family members 
> sharing last name. A key of last name + first name will have a high 
> cardinality and will make a good index.

Thanks for the explanation. I will index based on that. I decided to go 
with the temp table approach for now as this lets me work with queries 
that I can comprehend.
I a past post I wrote that I merge the arrays that I get for each table. 
While I in fact did that, I really need to do an intersect to create an 
INNER JOIN. I filter each table based on the contents or ranges of 
particular fields and only those items that have at least one row in 
each table are the ones that I want. Two tables can have only one row 
per item by design, so the distinct will come into play for only one 
query. With that I also do not need an array_unique as the intersect 
cannot have duplicate values.

Good stuff!

David