[dba-SQLServer] SQL Server Book

I plunked down a little over $50 today and bought a copy of "murach's SQL
Server 2008 for developers" book.  This is a 750 page tome (including a
couple of Appendixes) that include instructions for downloading SQL Server
Express (with Tools), the Management Studio, Books Online and two sample
databases.  There are 22 chapters in this book with heavy emphasis on T-SQL,
so I think this will be a very good study resource and prep guide for
passing the SQL Server Developer's exam - (i.e. 70-433).

 

In scanning this book prior to purchase, I noticed that each chapter ends
with a section of "Terms" that were covered in the chapter.  For instance, I
have seen frequent references to the term "instance" in Books Online, but
I've never been sure exactly what "instance" (or an "instance") means.
Based on what I'm reading in this book, an entity is a class of objects (for
instance "cars") and a particular car would be a member of that class, so if
a table represents a class of objects, then a row within the table would be
an instance.  (An instance is not a copy - it's a member of a class.)
That's where I was getting confused - I thought "instance" was a copy, but
apparently it's not.

 

What has me confused now is another section of the book where I read that
you can have "two instances" of SQL Server running simultaneously on the
same machine.  If I recalled correctly, that would seem to imply that an
"instance" is a copy!  (Maybe what that sentence was implying is that you
can have SQL Server running two different [application] databases off the
same SQL Server database engine simultaneously - so the two separate
databases are the "instances" - while the [installed] SQL Server database
engine is the entity.)

 

Hopefully this book will help me unravel all the terminology and clear out
the cobwebs.

 

Alan C. Lawhon