Re: [seul-edu] test programming before you begin database design :-)

[Dirk Schouten <schoutdi@knoware.nl>]

Hoi Mark,
Volgens mij hoort dit in jouw in-bakje. Maar misschien ken/heb je het al
Dirk
At 10:33 3-9-02 -0500, you wrote:
>Faking It - Simulated Database Queries @
>http://www.phpbuilder.com/columns/richmond20020827.php
>
>How often have you put off coding part of an application because the
>database wasn't ready?
>
>If you answered even once, you delayed a project -- which means you
>delayed your client. Maybe it was only a couple of days, maybe it
>was a couple of weeks. In either case, it took you a little longer
>to finish and your client had to wait. And we all know how patiently
>clients wait.
>
>But what if you don't wait for your DBA? What if you just... pretend
>the database is done... and start coding? You could get finished on
>schedule.   Or maybe even ahead of schedule. Now, if the application
>would just play along, if it would just fake it while you code...
>Playing Along
>
>Query simulations (QuerySims) were conceived by Hal Helms to remove
>the design and population of a database from the critical path of
>application development. Using QuerySims a programmer may proceed
>with writing and testing data display code while the DBA is
>designing the database, saving a significant amount of time.
>
>Alternatively, the database may be designed after the application is
>finished.  I've worked on more than one project were columns and
>even whole tables were never even used. It sounds counter intuitive
>to the way most of us learned to develop applications but by waiting
>we know exactly what columns and tables are needed and how best to
>group them for performance on the database end.
>
>When the database is complete, simply change the connect string to
>point to the real database and replace the QuerySim text with an SQL
>select statement that returns the appropriate columns. There is no
>need to modify your display code, because as far it could tell, it
>was already using a result set from the database.
>
>QuerySims are especially useful when following the FLiP methodology
>and using the Fusebox framework for application development, but you
>don't have to be using FLiP or Fusebox to use QuerySims!
>Database Abstraction
>
>Keeping your code portable from one database to another will
>increase its reusability tremendously, but this is virtually
>impossible using PHP's native database functions. The intelligent
>thing to do is to use a database abstraction layer that can
>interface with any database using common methods.  Even more
>intelligent is to use one that is already familiar to other
>developers, so when your code needs to be updated by your successor,
>he or she doesn't need to learn a new API in addition to the ins and
>outs of your application. (Remember this works both ways, things
>will be easier for you if the situation is reversed.)
>
>The original QuerySim was a ColdFusion custom tag that took
>advantage of ColdFusion's built in database abstraction layer and
>functions for populating a real query-scoped variable with data.
>Unfortunately, PHP doesn't have a built in abstraction layer we can
>populate with data. Since each database has its own set of functions
>for connecting, querying and manipulating data, we need a common
>interface for a clean switch from QuerySim to a live database.
>
>There are several very good database abstraction layers available,
>PEAR DB and ADODB are two of the more popular ones. This version of
>QuerySim is implemented as a database driver for PEAR DB.
>PEAR DB
>
>DB is a class package available from the PHP Extension and Add-on
>Repository (PEAR) project. Sean Cazzell's article will give you a
>quick synopsis of what PEAR is trying to achieve.
>
>If you would like to follow along with the tutorial, you may
>download the current stable DB package here . But one of PEAR's
>strengths is its close association with the PHP Group; PEAR and the
>DB package are included with the default PHP install, so you
>probably already have it!
>
>
>
>
_________________________________________
Dirk Schouten

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