Conceptual database questions...

[Bill]

Your questions are interesting because you are conceptualizing databases in
a very different manner than I do. I think of them as big spread sheets with
columns (tables) and cells containing data.

I have trouble with the cursor object to and never use it. I really like
using Trevor's libDatabase and I highly recommend it.

Also when I work with a database I design all the tables and fields first
and put some sample data in so I've never thought about what would happen
when there is no data (with MySQL you just get "NULL" in response to a query
when nothing is there).

The database query builder is also good when you want a very large table
with lots of fields to all be present on one card and you just go through it
to look at or edit the data. It won't allow you to add data and it is
difficult to use it for JOINS (viewing data that is a combination of
different tables from the same database).

Whenever possible you should design your table so that one of the fields is
a unique identifier that can be indexed. That index is what you use to link
data from that table with data in other tables (and also where the
spreadsheet analogy of database design falls apart).


On 5/26/05 9:32 AM, "Lynch, Jonathan" <bnz2 at cdc.gov> wrote:

> Hello everyone...
> 
> I feel like I am just not getting some basic concepts in trying to use
> the Valentina kernal for RunRev. So, I have a few questions:
> 
> 1) Is a base object (table) basically a set of columns?
> 
> 2) A base object can contain zero records, yet you are still allowed to
> set the value of a field in a base object. Does setting the value of a
> field, without any selected record, basically have no effect?
> 
> 3) Is the following the correct order of events for creating a record:
> a) Create database or make sure it exists
> b) Create table (base object) or make sure it exists
> c) Create columns in table or make sure they already exist
> d) add record, at which time that record becomes the selected
> record for that table
> e) insert information into that record
> 
> 4) Since a cursor is a selection of records, can you have a cursor if
> the table has zero records?
> 
> 5) When is it necessary, and when is it not necessary but probably
> better, to use a cursor rather than working directly with the base
> object?
> 
> 6) Do records have specific IDs, such that I could call up record 57 of
> base object "billingdata"?
> 
> 
> Thanks, and my apologies if I am asking ignorant questions for which I
> should know better.
> 
> Jonathan
> 
> 
> 
> 
> _______________________________________________
> use-revolution mailing list
> use-revolution at lists.runrev.com
> http://lists.runrev.com/mailman/listinfo/use-revolution
> 
> 

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