NYCPHP Meetup

[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
> 
> -- 
>  T H E   A N A L Y S I S   A N D   S O L U T I O N S   C O M P A N Y
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