Sorry to get technical on
you like that, without any warning, so to speak, I'll try to
more careful next time.
But since you are here,
we might as well go on, because it is kind of interesting,
in an abstract, obscure, arcane way. Well, ok, maybe I'm pushing
it, just a little.
Anyway, an Entity Relationship Diagram (or ERD
for short), is a way of visually
describing how a database works. Not that it explains everything,
but it does explain
quite a bit. Because a database works by being able to
link separate database parts together to
combine data to make information.
The database parts are tables of data, similar to,
but not the same as an Excel table.
In the diagram below, 4 tables are represented: Customers,
Orders, Order Details
and Products. When a sales rep signs on a new customer,
that data goes into the
Customers table. And when that
customer (or any other customer) places an order,
that order data goes into the Orders
table and the Order Details
new products are added to the product catalog, that data goes into the Products
Getting back to the diagram below, it shows the
pieces of data in each table, called
attributes (or data elements).
Each table is similar to a separate file and each group
of data elements for each row of the table is similar to a record in
the file. The ability
of the database to link together the separate, but corresponding records
from each table is what gives a database system
The database system uses a language called SQL
to allow techies to combine data
to make information. SQL is
also called Sequel (and often pronounced that way, on purpose)
and actually is an acronym for Structured
SQL is easy to learn at first, but gets complex quickly.
is proficient at analyzing, designing and building databases and systems, from the simple to the complex.
And we would be glad to help you with your system,
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