Another way that a field is placed into a separate table is if that field ("hobbies" or "favourite music genres") have been added to more than one table. When you add or remove a field from a table, CCK will alter the DB tables on the fly and move the data into and out of your tables. I was at the boston drupalcon and worked with KarenS at the sprint, she talked about how this works and that it's a bit ugly inside. She also mentioned that although it may seem that having the field data in separate tables may seem like a significant performance hit, after doing some testing, it's not as bad as you'd think due to the way cck does caching. I didn't fully understand at the time, but after poking around the code a bit, i can see how that might be so. ...alex... Gordon Heydon wrote:

Hi,

Yes this is correct, and there have been some people that will tell you to use multiple and shared fields as little as possible as it is a performance impact.

I have recently discovered that this is not true. All fields not matter what the type all have basically the same performance impact.

The basic rule with CCK is to keep the total numbers of fields per node as few as possible.

I have fixed this in Drupal 5, and just need to clean up the patch before I submit it.

Gordon.

Neil: esl-lounge.com wrote:

...

OK, I found the answer in the second half of this article on the db aspects of CCK:

http://www.lullabot.com/articles/an_introduction_to_the_content_construction...

the two fields (which were actually hobbies and favourite music genres now I recall...) both accepted multiple values so it seems that is the crucial factor in deciding whether a CCK field gets added to the db as a separate table or part of a content type table: that - and whether the field is shared between content types.

Neil

----- Original Message ----- *From:* Neil: esl-lounge.com <mailto:neil@esl-lounge.com> *To:* support@drupal.org <mailto:support@drupal.org> *Sent:* Friday, March 21, 2008 10:16 AM *Subject:* [support] CCK fields being created as separate tables in the db

I've been pulling my hair out about this for two hours. I have made a nodeprofile content type and am using cck fields to build it.

All the fields I created were added as columns to the content_type_nodeprofile table....except the last two which were added to my db as separate tables:

content_field_hobbies content_field_age

these were the last two I added and, also, I had a few problems with the "group" they sat in, so I ended up changing the name and deleting and recreating the groups at least once...may this have caused the issue?

I've tried totally deleting the relevant fields and groups and starting again, but they keep getting created as separate tables. Aagh!!

Basically, what is it that makes CCK create a field as a separate table instead of putting it as a column inside the content type table?

Neil

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