System Requirements… Really?

So this surprised me, but Mark Long said to be sure to know the system requirements for installing SQL Server 2000. Apparently it is a commonly asked question on the certification test (MCDBA).

So the two most commonly asked system requirement questions are about the processor and the RAM needed to install SQL Server 2000. You need a 166 MHz processor or high and you need 128 MB of RAM on Windows XP. He said you might be asked about the hard disc space (250 MB) needed for an installation, so it’s also good to memorize that. I thought it was strange that these questions would be asked now seeing as how its would be difficult to find a computer that did not me these requirements. However, the questions make more sense if you look at when they were written, and if you look at them as knowing SQL Server better over all.

So, you may ask, if you can’t see what your working on how do you work with it. Well, you work though the control panel SQL provides. Though this you can view what is happening in the database, update a database, and also send queries (requests for specific information). However, this is a screen that only the administrators and developers usually see, as the functions of SQL exist only as background of a computer interface.

You navigate with this screen which looks very much like the drive exploration on most computers. Though it looks complicated it is fairly easy to understand. and I’ll explain it in more depth later.

Also as a side note I am taking my SQL pictures from the videos because I believe Half Price Books might be angry if I published screen shots of server side applications.

Two Main Types of Databases

According to Mark Long there are two main types of databases. They are the Online Transaction Processing (OLTP) and the Online Analytical Processing (OLAP) databases. Most databases fall somewhere in between these to types.

The course that I’m taking focuses on the OLTP database, and I will mostly be writing about this type for the foreseeable future. OLTP are designed for a high volume of input, but are slow to retrieve data. They allow for simultaneous updates and are quick and responsive to updates. They are normalized . Normalization refers to the way a database is organized, meaning that it has several interconnected tables. These tables are linked though shared key words. Because this database has several interconnected tables it has little wasted space. For example, if a database stores someone name and addresses along with other information, but has two slots for addresses the second address would be on its own table. Thus if someone only had a single address entered in this database it would not be creating and storing an empty slot, and only people with multiple address would appear in the second address table.

OLAP databases are typically called data warehouse or a data mart and are mostly used for data analysis or data mining. I am interested in learning about this database but unfortunately it’s not covered in this course. They are designed for fast retrieval of data but are slower to accept input. They are denormalized. As you might imagine denormalization is basically the opposite of normalization. Therefore in denormalization you have fewer, larger tables that hold data. OLAP databases tend to be very larger than OLTP databases.

What is a Database?

Sorry it’s been a while since my last database related post. However, I’ve been working through the VTC site and am very pleased with it thus far. So, because I’m behind on my posts I’m going to rattle off several in a row so I can catch up.

The first step in learning SQL Server 2K always involve a brief history of SQL and the explanation of databases in a general since. (I say always, but mean in the books that I’ve started to read and in this video format.) I will not go into the background of SQL as you can read about it on Wikipedia. Instead, I will attempt to explain databases.

I probably don’t need to write this but, databases are spaces where information is stored and can be referenced. They are used by all businesses, be it a receipt book, file cabinet, or SQL. I as you might expect will be focused on SQL. Unlike most things made, SQL databases are not usually seen in their entirety. The most commonly used metaphor is to think of a database as a stack of Excel spreadsheet pages. However, since most databases consist of multiple tables that are cross referenced they are usually shown as flow charts. The flow chart can map the idea of a data base, but you never see the whole thing at once. When Z was explaining this concept he had me hold out my hands to imagine working on something then held a piece of paper in front of my face and said “It’s like this.” I feel that his might be the best illustration, if not it’s certainly the most fun.