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as other information that may be optional, such as the person’s birthday,
whether you sent a Christmas card to the person last year, or how much
money the person owes you.
SQL Server is designed to create and manage computerized databases that
are similar to these noncomputerized databases. Like your address book or
shoebox full of tax records, a SQL Server database is a collection of records,
and each record is a collection of fields. The biggest difference is that in a
SQL Server database, the information is stored on a server computer’s hard
drive rather than in a shoe box.
What Is a Relational Database?
“Say Al, do you think they call it a relational database because it’s good at
dealing with relationships?”
“I don’t think so, Tim.”
SQL Server is a database management server that creates and maintains rela-
tional databases. Unfortunately, the term relational database is one of the
most used and abused buzzwords in the computer business. The term has at
least three meanings. A relational database can be:
✦ A database in which data is stored in tables: In a relational database,
groups of similar records are called tables. A database usually consists
of more than one table — in fact, it isn’t uncommon for a single data-
base to have dozens of different tables. You can establish relationships
between and among these tables based on common information. For
example, a sales database might contain a table of customer information
and a table of invoices, with both tables containing a customer number
column that establishes a relationship between the tables.
✦ A database model based on a Conehead branch of mathematics called
Set Theory: This is actually the most technically precise definition of a rela-
tional database, but only computer geeks know or care. Contrary to popular
belief, the term relational database is not derived from the ability to create
relationships among tables, but from the term relation, a mathematical term
that refers to the way data is arranged into tables of rows and columns.
(It’s a little known fact that relational database theory was developed at
around the same time that the Coneheads from the planet Remulak first
visited the Earth, back in the 1970s. I have always suspected that these
two developments are — dare I say it? — related.)
✦ A database that’s accessed via SQL: SQL, which stands for Structured
Query Language, provides a practical way to access data stored in rela-
tional tables. A database that’s based on SQL is inherently relational
because SQL stores its data in tables and is based on Set Theory. SQL
Server, as its name implies, is based on SQL.
What Is a Relational Database?
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