Meeting: SQL and the DataPower Database
Database developer Nick Mason talked to us about the use of Standard Query Language (or SQL) for getting information out of databases. Armed with a suitable tool – such as R-Comp’s DataPower 3 – some very complicated-looking questions can be easily answered using only a few simple instructions. Nick showed how the use of SQL can complement the graphical query tools that are also offered by RISC OS’s “DTP-style” database.
Report by Rick Sterry and Steve Fryatt
Our guest at the March meeting was Nick Mason, an IT consultant operating as Arcamex Ltd. His talk was a short introduction to SQL (Standard Query Language) for databases. The particular database he was using to demonstrate SQL was DataPower 3, which is now developed and distributed by our old friends at R-Comp. However, this talk was much more about SQL than DataPower.
Nick started by explaining that, despite what we may have thought from his name, he was not the drummer from Pink Floyd. He even came prepared with a photograph to help him prove this, although a number of audience members seemed to think that they could see a definite resemblance. With the important issues out of the way, the main part of the talk began.
The first thing that became apparent was that the nice thing about ‘standards’ is that there are so many to choose from! SQL is no different in this respect, and like the programming language BASIC, SQL exists in a number of different ‘flavours’ with much in common, but also many syntactical differences to trap the unwary. Apparently, this helps keep Nick gainfully employed!
DataPower 3 has several different ways of sorting, searching and selecting data. In common with many ‘simple’ databases, the criteria can be entered directly into a layout view; in keeping with its relational abilities, it is also possible to directly access the fields within the tables that make up the database. These make accessing the data a relatively simple matter of drag-and-drop.
Another alternative offered by DataPower is SQL. Switching from the graphical views into SQL causes any existing criteria to be ‘translated’ into SQL, while switching back causes the reverse to happen – to a limited degree, at least. This can be useful for beginners, as it makes it easy to see how different search criteria would be represented in SQL, as well as seeing the effect of new SQL commands through the graphical interface.
Nick then took us through a number of simple examples of how SQL can be used to select and sort data from an example ‘dummy’ database. You can see a similar presentation, with the DataPower file that Nick used and all the examples if you visit Nick’s web site at www.arcamex.com and then click on Products followed by RONWUG Presentations; alternatively, follow the direct link from the members’ area of the club website. We have no audio or video of Nick’s talk, nor a full write-up, but the information you will find on Nick’s site will certainly give you an idea of what it was about.
It was a short talk, perhaps so as not to frighten anyone, and left us wanting to know more. It succeeded in generating enough interest for us to invite Nick back at a later date so he can tackle the subject in a little more depth.
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