rmello at fslc.usu.edu
Fri Jun 10 09:14:41 MDT 2005
On Thu, Jun 09, 2005 at 12:57:27PM -0600, Nicholas Leippe wrote:
> The NULL debate is nearly as bad or worse than the vi vs emacs debates by the
> academics. IMO, those that argue for strictness to the relational model
> haven't written a line of production code in their life. In many cases NULL
That's quite a claim. Can you back it up?
> is a practical shortcut to a much more laborious schema.
These shortcuts can usually be avoided, keeping things even simpler (no
need to check for nulls all the time) and faster.
> The 'proper' relational way is to have another table that contains a row or
> not depending on the existence of the data. Then, you join to that table,
> and if there is no matching row, that is how you'd know rather than using
> NULLs. Just sticking in a NULL in the first table can avoid the need for
> join entirely. For a lot of data, this is IMO the best solution because it
> MySQL has a few nice functions that help make NULLs less painful.
> COERCE() accepts a list of arguments and returns the first that is not null.
> CONCAT_WS() can be used to concat a bunch of values, ignoring the null ones:
For the sake of information, the standard SQL equivalents of COERCE
(supported in PostgreSQL) is COALESCE. Not sure if there's an equivalent
Oh my GOD! A Prompt!!! HELP!!!! A PROMPT !!!!! HEEEEELP !!!!!!!!!!!!!
More information about the PLUG