An Intro to Databases
Where the presentation layer governs the user's interaction with an ebusiness system and the application layer coordinates its behaviour, it's the data layer that brings an ebusiness system to life -- structured information defines entities and relationships representing the actual business and affairs the system exists to support.
Here, to introduce the topics of databases and business intelligence, we will review some key terms.
|What is data?||In a broad sense raw data are numbers, characters, images or other outputs from devices which convert ideas or physical objects into symbols. Raw data is a relative term; data processing commonly occurs by stages, and the "processed data" from one stage may be considered the "raw data" of the next|
|What is information?||Data on its own has no meaning, only when interpreted by some kind of data processing system does it take on meaning and become information. People or computers can find patterns in data to perceive information, and information can be used to enhance knowledge. Since knowledge is prerequisite to wisdom, we always want more data and information. But, as modern societies verge on information overload, we especially need better ways to find patterns.|
|What is an entity||An entity is something that must be distinctly represented in an eBusiness system. People, organizations, accounts, products and services, customers, orders, and suppliers, are all examples.|
|What is persistence?||For our purposes think of persistence as the characteristics of continuity, reliability, and connectedness. Persistence of data and business logic, over time, and throughout an ebusiness process, even as it spans multiple software components, or even as a system is stopped and restarted, is critical to creating a seamless and stable system.|
|What is a Database?||A database is an information set with a regular structure|
|What is a Relational Database Management System (RDMBS)?||A database management system (DBMS) is a computer program (or more typically, a suite of them) designed to manage a database, a large set of structured data, and run operations on the data requested by numerous users. See: relational databases.|
|What is the relational approach to managing data?||When managing data using the relational approach information is represented by data values arranged in mathematical relations. The data is operated upon by means of a relational calculus and algebra. The relational model permits the database designer to create a consistent logical model of information, to be refined through database normalization|
what is the difference between a normal DBMS and a RDMBS?
Posted by: Krista Mackenzie | Nov 15, 2007 11:23:22 AM
Does the DBMS run on an OS like Windows? or is it different
Posted by: Billy MacDonald | Nov 16, 2007 3:58:55 PM
As far as I know, a RDBMS is just a type of DBMS that stores and organizes data in the form of tables. Most Database's would probably use this type of DBMS as it is a very efficient way of sorting data. There's no real difference between the two, its just like saying that chocolate chip in a type of cookie.
Posted by: Jeff MacKenzie | Nov 18, 2007 3:26:12 PM
We'll cover this in class.
Posted by: Mark | Nov 18, 2007 6:06:04 PM
I agree with Jeff. I think that the RDMBS is basically just taking the DBMS a little farther....almost into more specific parts. I like to think of it as more of less just breaking it down into a more specific group such as a Corolla S as opposed to simply a Corolla or even a Toyota car.
Posted by: Kate Murnaghan | Nov 19, 2007 1:13:00 AM
Thanks for the clarification between the two, I was wondering about the difference between the two as well.
Posted by: andrew black | Nov 20, 2007 12:12:33 AM
I think every data base is relational. In order for a database to store and retrieve information there must be a mathematical system to define the logic of the system. If not data would be stored at random and finding a specific piece of data would be near impossible.
Posted by: Chad hayward | Nov 20, 2007 11:56:25 AM
Well Chad, I think you're right but be careful.
You have to understand how the words database and relational database are used in practice.
A hockey card collection is a database of sorts even if it has no logical order.
Posted by: Mark | Nov 20, 2007 12:10:54 PM
Hockey cards...man dear do I have a database under my sons bed!
Posted by: Frieda MacLaren | Nov 20, 2007 12:32:35 PM
Mark, how do you get into that powerpoint presentation? I found it earlier but can't seem to find it again? I think it would help me study. Thanks.
Posted by: Krista Mackenzie | Nov 21, 2007 4:42:20 PM
It's linked to in the next post.
Posted by: Mark | Nov 21, 2007 10:49:45 PM
I like how information is referred to as patterns in data. Never really thought of it that way before but that makes sense
Posted by: Chad MacLean | Nov 22, 2007 12:19:36 PM
I found these definitions to be really helpful in understanding databases. So if hockey cards are a database then how would it be possible to make it relational.
Posted by: kyle macdonald | Nov 22, 2007 12:35:52 PM
Good question! We will cover it in class.
It's fair to say that you would need some kind of software tool to make it relational. There is information within a hockey card that relates to other cards, teams, stats, etc...
A hockey card collection that was transformed into an online relational database would allow you to sort and sift the information along any of this lines.
Imagine switching between a team roster view which would list points, and a league scoring view. Same information, captured and stored once but viewed from many different angles.
Posted by: Mark | Nov 22, 2007 12:50:36 PM
The hockey card example was really helpful
Posted by: Nick Drake | Nov 27, 2007 10:24:35 AM
Mark, did you say that we have to know how to make a database? What does that mean?
Posted by: Krista Mackenzie | Nov 29, 2007 6:34:55 PM
Do you just mean that we would draw a database with it's five components?
Posted by: Krista Mackenzie | Nov 29, 2007 6:52:34 PM
I actual understood this right away. Way to reference hockey.
Posted by: Colin Butler | Nov 30, 2007 11:23:40 PM
We use the wiki's explainations or here?Seems have some differences.
Posted by: XiaoJiang | Dec 1, 2007 3:45:28 PM
When you gave a definition of relational database vs. relational database model is the difference basically just that a relational database is just describing the concept itself and its content then a relational database model actually describes the concept based on its structure?
Posted by: Krista Mackenzie | Dec 1, 2007 4:24:41 PM
Im starting to not like hockey...haha thats actually a really good example. is it the same for any sport statistic thats online? Like if it was an exam question, could i use the analogy of a basketball games stats being posted online? and the whole games stats can be posted once...then broken down by looking up..top rebounder or foul shooter? or am i way off here..should i stick with hockey..?
Posted by: Susanne | Dec 3, 2007 4:55:20 PM
I don't get the relational approach to managing data.
Posted by: Colin Butler | Dec 3, 2007 10:57:26 PM
I think that basketball analogy works. I came up with a soccer one.
Posted by: Colin Butler | Dec 3, 2007 10:58:28 PM
I like the way that Krista broke it down and explained the difference between the two in just a few sentences. I think you can apply this to any sport really if you start out with stats for everything then break it down into the smaller components that branch off.
Posted by: Kate MacDonald | Dec 4, 2007 1:15:41 PM
From what I understand a Relational Database is a database based on the relational model, which is based on tables. Is that right?
Posted by: Erica Wagner | Dec 4, 2007 4:12:36 PM