[nycphp-talk] naming identifiers (was: understanding NULL)
Kristina D. H. Anderson
ka at kacomputerconsulting.com
Sat Aug 29 23:23:29 EDT 2009
>Your big mistake was delimiting the identifiers when creating the
table.
>
> "Identifiers" are table names, field names, index names, etc. The
> "delimiter" for these is "`" in MySQL. When you use the delimiter
around
> the identifiers, the database allows you to create nearly any name
you
> can possibly think of, including "reserved words." Reserved words
are,
> well words that the system has reserved for its own internal use, so
> should not be utilized by users.
This cannot possibly be stated often enough.
Kristina
> Hi Bev:
>
> > Creating a field/variable named desc and spending hours trying to
figure
> > out why MySQL was balking at my query with its typically enigmatic
error
> > messages.
>
> Your big mistake was delimiting the identifiers when creating the
table.
>
> "Identifiers" are table names, field names, index names, etc. The
> "delimiter" for these is "`" in MySQL. When you use the delimiter
around
> the identifiers, the database allows you to create nearly any name
you
> can possibly think of, including "reserved words." Reserved words
are,
> well words that the system has reserved for its own internal use, so
> should not be utilized by users. As you've now discovered,
delimiting
> identifiers when creating tables is the genesis of a world of pain.
>
> If you tried to create a table with a name called "desc" in it
without
> delimiting it, MySQL would have complained to you up front, saving
you
> the agony.
>
>
> > Or like the time (very recently) when I was converting timestamps to
> > calculate the number of days between two given dates. I used the
> > number_format() function...
>
> Uh, just making sure... Did you convert the timestamps via
> number_format() then do the math? Ouch. This is the kind of stuff
the
> date functions, like date_diff(), etc, in MySQL and PHP are for.
> Faster, more accurate, easier. Then format the result.
>
> --Dan
>
> --
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