Which finder syntax would be preferred as far as being the most database agnostic?

rubyonrails-talk
#1

Which finder syntax is preferred? Or are they the same?

I'm developing on sqlite and I've posted the result of each
query...they kind of look the same but not really. Would this scale
to say, Mysql or Postgres? Thanks for any advice.

named_scope :disabled, :order => 'name', :conditions => { :disabled_at
=> !nil }
SELECT * FROM "groups" WHERE ("groups"."disabled_at" = 't') ORDER BY
name

or

named_scope :disabled, :order => 'name', :conditions => ['disabled_at
<> ?', nil]
SELECT * FROM "groups" WHERE (disabled_at <> NULL) ORDER BY name

#2

I for one prefer the first syntax, since it eliminates SQL from the
ruby code, but that's just my preference.

Cheers,
Tim

#3

Lee Smith wrote:

Which finder syntax is preferred? Or are they the same?

I'm developing on sqlite and I've posted the result of each
query...they kind of look the same but not really. Would this scale
to say, Mysql or Postgres? Thanks for any advice.

named_scope :disabled, :order => 'name', :conditions => { :disabled_at
=> !nil }
SELECT * FROM "groups" WHERE ("groups"."disabled_at" = 't') ORDER BY
name

or

named_scope :disabled, :order => 'name', :conditions => ['disabled_at
<> ?', nil]
SELECT * FROM "groups" WHERE (disabled_at <> NULL) ORDER BY name

Use the first syntax -- the second one is incorrect. I don't know if
this is true in SQLite, but in the other DBs, NULL = NULL returns NULL,
so your <> NULL construct will return TRUE in all cases, and so it is
pointless. In the first case, Rails automatically generates the proper
syntax.

Best,

#4

> named_scope :disabled, :order => 'name', :conditions => ['disabled_at
> <> ?', nil]
> SELECT * FROM "groups" WHERE (disabled_at <> NULL) ORDER BY name

Use the first syntax -- the second one is incorrect. I don't know if
this is true in SQLite, but in the other DBs, NULL = NULL returns NULL,
so your <> NULL construct will return TRUE in all cases, and so it is
pointless. In the first case, Rails automatically generates the proper
syntax.

Actually NULL <> NULL is also NULL. Hooray for 3 way logic. (doesn't
mean the OP's would work though). In general I tend to use the hash
form of conditions when possible, but that's not always the case.

Fred