An app needs a “Setup the Database” routine correct ?
I do not use schema classes at all to represent tables in a database – I use the approach for dynamically create a unified table class template from the database model at the database itself presented by Dan Ridinger at a Euromnis event a number of years back. This to prevent having potential version conflicts later on. The resulting table class template from this operation is then used to create a row var template that will be copied during the code execution. Copying from a row var template is about three times faster than defining it from a schema class. This might not matter much for a fat client app but for apps running on an application server with hundreds and thousands of simultaneous users it matters a lot. Presented these approaches and some others in regard to session pools, SQL workers and push approaches using object centric approaches at the German conference 2017.
The experiences from this is quite interesting – the internal processes within Omnis app server itself are often aggregated within 0.2-0.5 milliseconds – the majority of the time consumed for delivering a request to the clients are used for the Postgres database operations and the most time demanding operation is the delivery of the results to the client across the internet.
I strongly recommend that you look into the approaches for session pools, SQL workers and even push early in the process of planning your application. And I recommend also to look into the overall structural architecture of your system to allow it to be modular not only in regard to data / information access but also in regard to the user interface functionalities.
Take care, all the best…
> 24 jan. 2018 kl. 23:31 skrev Phil (OmnisList) via omnisdev-en <email@example.com>:
> Hi Das,
> Yep, like others, we do that, the installer creates a database and a default user…
> But then the Omnis code creates tables and columns from its own Schema structure.
> Any changes down the line in the schemas are also handled by the code, so modifications…
> Be careful of schema versions, if someone logs in with an old lib, you don’t want the code to revert to an old schema definition, potentially losing columns (fields) of data.
> We store the database structure version within the database, so it knows if it can be updated.
> Joins, if your using tables for queries then check out the $fromclause…
> this is a good place for joins leaving the where clause to do its job…
> Phil Potter
> Based in Chester in the UK.
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