Rudderow, Evan ([log in to unmask]) wrote:
: "<Elbert E Silbaugh>" <[log in to unmask]> wrote:
:  While I know that ODBC is supposed to shield us from these kinds of
: differences, I wonder how realistic that hope is...
 
What we (and most other vendors) have to do on attaching to an
ODBC driver it have a quick conversation to check which features
and functions the driver supports. Thus, when you run say Axiant
or Impromptu for example, we establish what we can pass down to
the driver. If you have Impromptu3 we ship an ODBCtrace tool
which captures the conversation.
 
We added this tool because of the number of problems people ran
into which turned out to be ODBC driver bugs/limitations which
our support people frequently had to track down for customers.
 
: BTW, aren't SQL based databases usually touted as adhering to some kind of
: standard?
 
ODBC is a spec created by Microsoft which draws from the work of SAG,
X/Open and ISO/ANSI. ODBC 2.x is the current spec level which expands
upon the 1.x spec and accounts for more of the ISO SQL-92 spec.
 
Most database vendors are close to being entry level SQL-92 conformant
(some have FIPS-127 certification which uses ISO/ANSI SQL specs
as it basis). Most often now, they are kind enough to document
where their extensions are and in some casese include FIPS flagger
support to warn/error when non-standard syntax is being parsed.
 
However, life being like it is, vendors are also supporting
features that are spec'd for intermediate and full SQL-92 as well
as the SQL-92 draft. My recommendation to you if you are concerned
is to buy at least two books which I recommend in the Axiant
Migration books. One is by Gruber published by Sybex and the
other is by Melton and Simon published by Morgan Kauffman.
 
The former is a very cheap guide to SQL-92 and clearly denotes
the levelling rules of the grammar. Melton's book does a very
good job of explaining the meaning and why's of the SQL-92
standard (he was the editor for ANSI). Another worthwhile
purchase is a recent book by Joe Celko published by M. Kauffman
called SQL for Smarties.
 
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