Hi,
here it is what i’m looking for:
A course about SQL and the most important for me is how to write relations between each elements in a schema.
For my diploma, i have some texte that explains relations betweens different elements. It can speak for instance about how planes work and how they’re managed. It can be how “trash can” are handle by a company…
With these information, i have to create a schema with relation between each different elements.
And later on, they modify how it work so i have to retranscribe it in my schema.
I think it is called UML. But different technic can be used.
I think i have some thing about UML on my computer but i wanted to know if you guys had some very good ressources. And even more if it have real context exercices in it.
I think you might be mixing up your terminology here, UML has nothing to do with SQL or even databases. UML is a “graphical” language used for creating diagrams related to software engineering: Unified Modeling Language - Wikipedia
Hi, i really thank you with the time you put in your response.
So i’m even more sorry to say you i explaned myself very poorly.
I have to do a new modelization of the original database.
And this question can be threated with a Class Diagram, a conceptual schema (MCD <=> CDM) or a relational schema:
If you’re going to be doing relational database, you need to be familiar with the process of Normalization.
Ideally, you don’t want the same piece of information/data to be repeated across multiple tables… because when you update one table, you’d have to update the others too… or if you have data inconsistency, you won’t know which version is the wrong data because you have 2 different data stored in 2 different tables.
So by storing unique pieces of data per table (and all these data tied only by an record ID or index ID), you can construct your SQL to do JOINs and build the dataset that you want.
