Re: best stategry: check before create

[prev] [thread] [next] [Date index for 2005/03/18]

On Mar 17, 2005, at 11:10 PM, Ofer Nave wrote:

> 1) It will hit the database for every title.  I could avoid this by 
> building a quick hash of all titles already in my DB and checking 
> myself in perl, then calling 'create' for the new ones, but that's 
> less CDBI-ish.

Then you are trading more small lookups for a big data transfer and 
memory usage.   If you are concerned about it you should make a test to 
see if it's even faster.   How many titles do you need to compare 
before it's faster?

> 2) It uses the same data structure to both 'find' and 'create' - 
> meaning you can't say "just match on title, but if you don't find the 
> title, then create it with that title as well as this body and this 
> other misc data".  Since it returns the object, I could then set the 
> non-matchable fields afterwards, and then call 'update', but that's 
> two DB hits instead of one.  Not a big deal, but I am wondering if 
> there's a more elegant CDBI solution that I don't know of.

Do a search on the title and then either update or create as 
appropriate.

If the data load is truly high it should be a little faster to do a 
"insert ... on duplicate key update ..." statement if your MySQL is new 
enough to support that.


  - ask

        -- 
        http://www.askbjoernhansen.com/