Discussion: Design a database
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Vieux 26/03/2008, 21h48   #5
Guillermo_Lopez
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Par défaut Re: Design a database

On Mar 26, 1:54pm, RogBa...@gmail.com wrote:
> On Mar 26, 11:56am, panab...@gmail.com wrote:
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> > On Mar 26, 11:37pm, RogBa...@gmail.com wrote:

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> > > On Mar 26, 10:43am, panab...@gmail.com wrote:

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> > > > Hi,

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> > > > I need to design a database, but i i just don know if i am doing it
> > > > correctly.

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> > > > Basically, i have equipment which is sending me a lot of gauges
> > > > readings (high limit, low limit, current level), electrical readings,
> > > > hydraulic readings, alarms levels such as Fuel level, temperature
> > > > level, etc etc, about 200 different types of readings, continuously.I
> > > > may have different types of equipments and although most of the data
> > > > are the same, except some data types and its availability may be
> > > > different., depending on the type of equipment.

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> > > > I want to keep this readings in a database, and this database will be
> > > > updated constantly. I will update display using the readings from the
> > > > DB. Eventually i also want to use the data from the database to plot
> > > > chart or run simulation.

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> > > > Should i create all of this different gauges readings in one big
> > > > single table? If i do so, i only have one long row of data then for a
> > > > particular equipment.If i put in different table, i can't see how i
> > > > can create relationship among my tables with such kind of data.

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> > > > Can you on the possible ways of putting this equipment real time
> > > > readings into DB?

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> > > You don't necessarily have to have a relational database, it is just
> > > useful for data integrity. You could have one table per piece of
> > > equipment if that makes sense. If you started repeating data, that
> > > would be a prompt to pull it out and make a related table.- Hide quoted text -

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> > > - Show quoted text -

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> > In this case, i most probably have only just one row of data, with
> > possibly 200 columns to cater for all the readings i get from my
> > equipment, in one single table. Does this sound ok..?

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> > if i need to plot data later, should i use fix time stamp interval as
> > the row in my table?- Hide quoted text -

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> > - Show quoted text -

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> 200 columns is fine. I am not sure what you mean about the time stamp
> as a row. It is common to use a column to hold a timestamp value.- Hide quoted text -
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> - Show quoted text -


Pan...

First thing you need to know is how are your readings done. Is it done
every x amount of time? Do you have to prompt for each readings? Do
you get a table (excel) emailed to you every x amount of time.

You mention Constantly, but that is not a good word to use when
recording data. You might record the data every second, milisecond,
nanosecond, and still not constant. However, that is good news.

I would suggest you have two tables. One for machines and the other
for readings.

Your [Machines] Table has all the information for each of your
machines plus a MachineID to identify each machine (This should be
however your source information identifies each machine). Your
[Readings] Table will have those 200 readings plus a few more, should
be like this:

[Readings]
===========
[ReadingID] (autonumber) key
[MachineID]
[TimeStamp] (date/time)
[electrical]
[hydraulic]
[Fuellvl]
[Temperaturelvl]
...
[etc]

Now each row has the readings for one machine at a particular time. So
then if you filter on Machine 1 then you will see all your readings
across time for machine 1.

Also, if you do not have any information on the machines only the
MachineID then there is no need to have the [Machines] Table.

- GL
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