Re: Relational Databases

Stephen,
Thanks for your explanation. Between you and Brian (who also answered about 
transparency) I'm beginning to get a handle on db connectivity. I wish the 
books could explain it as simply as y'all can.

Regarding good books - I recently upgraded to MS Office 2000 and wanted to 
get a handle on the changes in Access. After much agonizing over texts, I 
found Que's "Special Edition Using Microsoft Access 2000". Not only info on 
ODBC but also on where MS is going with dropping Jet and implementing a 
subset of SQL7 called MDE (Microsoft Database Engine) into Access 2000. 
Tread lightly here, MDE 1.0 and all the related stuff like ADP and DAP is 
nice to see but nowhere near production ready. They're really pushing web 
connectivity to new levels here. They're also pushing acronyms to new 
heights :~o
Thanks,
Dave G.

At 08:38 PM 4/7/00 -0700, Stephen Johnston wrote:
>Dave-
>
>         What is generally meant by database transparency, or at least as 
> I see it, is that your code does not rely on any particular database. 
> There are many types of databases out there, with their strengths and 
> weaknesses, but not all of those strengths and weakness rely on the way 
> that interacting with the database them is coded.
>         If you distill it all down, there is a very large common set of 
> functionality in databases. This common set of functionality is exposed 
> by ODBC and similar APIs. ODBC stands for open database connectivity, and 
> that is the idea. Its called abstraction in other circles.
>         Basically for MANY purposes all you want is a record of a 
> database given to you by a SQL statement. Do you really care how the 
> database gets it to you? Well the quick answer is no. The long answer is 
> that certain database are better with certain types of data, so you 
> might. With ODBC you can start with  Access and use the common 
> functionality in Access for say 10 concurrent users doing simple selects 
> (like select ID, name from users) at say 5,0000 transactions a day. These 
> numbers are not based in any hard data on access really they are just for 
> example. You could take the same code and transfer the database structure 
> to Oracle and do 2,000 concurrent users doing 4 million transactions. The 
> ONLY thing that has to be changes is that the database structure has to 
> be recreated and a few simple setting in ODBC. THAT is database transparency.
>         It starts to fall apart when you start to get into the really 
> neat stuff that different databases have to offer, but it sure carries 
> for the bulk of things you will want to do. With the risk of alluding to 
> information that I don't have URLs for... There are some really good 
> books and articles on how ODBC came about and the impetus for it. It can 
> give you a good insight into general coding practices and databases if 
> you read them. Anyway, that's my 2c.
>
>Have A Good One-
>Stephen Johnston

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