Tutorials On Database Management

I'll try to be as simple as possible with my little knowledge of DBMS:

A database is similar to a data file in that it is a storage place for data. database does

not present information directly to a user; the user runs an application that accesses data

from the database and presents it to the user in an understandable format.


A Relational Database is the most effective way of organizing your data in a database. In a

relational Database, data is collected into tables called Relations. Hope you remember that

your table is built of columns and rows,  bla blahh blah. But, before i go on, there are

some terms you've got to be familiar with in DataBase Management System (DBMS) which are:


1. Data Entity: Some 'thing' that is to be stored for later reference.The Storage medium may

be either a disk or tape, or on a paper for manual systems.). It is a logical representation

of data. Which later becomes your table. i'll explain later. Example in a school system: The

Student, Lecturer, Course are all examples of Entitites.


2. Data Attributes: It is a piece of information that describes a data entity. The identified

attributes of the Entity Student are: MatricNo, StudentFullName, Age, Gender etc.


3. Data Association/Relationship: This indicates that a relationship exists between two

entities.For example: There is a Relationship between the Student and the COurse Entities. A

student is expected to offer at least 1 course. Hence, the fact that a student can offer more

than one course makes the relationship a one to many relationship.

* Your entity/Attribute is always uniquely named in the singular and written in Capital Letters. e.g STUDENT and not STUDENTS, likewise COURSE and not COURSES.

Types of Relationship includes:
One-to-One
One-to-Many
Many-to-Many (this can be further broken down into 2(one-to-many relationship)

to be continued,

you can try this out.
List out the entities in a Supermarket system, and state their different attributes.


Byee!

I'D have loved to see the solution to the question. Nonetheless, let's see how far i can go for 2day!

Key Attributes: add this to your list of terms
You remember what attributes? By key attributes: it implies those attributes that makes you to uniquely identify an entity. There are 4 types of Key attr.
1. Primary Key; 2. Foreign Key; 3. Candidate Key; 4. Compound Key (when you have two primary keys to identify a particular entity/Table)

Primary Key: This is the unique identifier of an entity/table. e.g the difference between 2 students in the same department is the Matric Number. Hence, Matric no is the primary key for the entity STUDENT. The student name(another attribute) cannot be a primary key because, it's quite possible to have 2 or more students with the same surname & initials, that is while name won't serve as a good primary key but the student Matric because 2 students is expected to share the same Matric no.

Let's consider a university STUDENT with the following details.

STUDENT
MatricNo
FirstName
MiddleName
LastName
Age
Gender
CourseCode
CourseTitle
LectuerId
LecturerName
Department

*******the STUDENT is the ENTITY while the underlining details are refer to as attributes***
(All this terms come to your mind when u are considering a typical university student, But most of the attributes we have in here can as well stand as seperate ENTITIES e.g. LECTURER, COURSE etc. this is what we call an UNNORMALIZED entity, because there are some attributes inside that are supposed to be separate entity ). this will lead us to NORMALIZATION in our next class! Note,each entity is expected to have a unique identifier(Primary Key)
When you have more than one Identifier for an entity, you call Compound Keys
A Foreign key is when you have the primary key of an entity/table in another entity/table for easy referencing.blah blah blah, see you next time.

try this out. from the unnormalised list above, identify the attributes that can serve as a separate entity and write out their attributes.

I'll do this:
DEPARTMENT
departmentID
departmentName
HeadOfDepartment etc.

Hi, sorry for the suspense, just that i've been quite busy.

On Normalization,
A Normalised data is a clean data, you'll often hear this word 'Normalised/Normalisation' in DBMS because a normalised data is good for OLTP -Online transaction processing, (While your Unnormalised data is good for analytical processing).Normalization provides you with a consistent data without redundancy. There are Normalization rules which you must apply to your unnormalised data(e.g STUDENT entity) to make it Normalised! (I'll summarise the rules here, but u can pick up your textbook to learn more)
The first rule says that you must identify and remove all Repeating Group attributes into another Entity.i.e There should be a one-to-one relationship between the instances of an entity and the rows of the table.
The 2nd rule says that you must identify and remove attributes into another entity which are only partially dependent on the primary key and are also dependent on one or more other key attributes; or which are dependent on only part of the compound primary key and possibly one or more key attributes.

the 3rd rule says that you identify and remove into another entity those attributes which are dependent on a key other that the primary(Compound) key.

The explanation to this would have been a lot easier with some diagrams(The Entity Relationship Diagram), but can't place my diagrams here.

Database management is actually all about managing your database. Remember, Database (DB) is just like a container where you store information.DBMS helps you to well organise your data in the DB server. (

I would love to have that, my email is olatundelanre@yahoo.com

Thanks

@OlowoTee,
Thanks so much for your help thus far. But sorry, i have to take a break at thins point, because I have exams to write.
I hope we can resume afterwards.

@Otuonye

Guy, I wouldn't mind if you'D be gracious enough to forward the SQL material to me via: jackelony@yahoo.com
Gracias

I'D be most grateful to benefit from the SQL Server 2000 material. My e-mail address is bijorium@gmail.com . Thanks

Please I need the complete tutorial on SQL server 2000.
I want to be an ardent Database Administrator and Network Expert, majoring on the information(data) security.
my e-mail address is  royalkings2nice@yahoo.com
Thanks Jo

Thanks OhGrey for sharing that piece of information with me. I've been able to upload the ebook now tanx to Rapidshare.com.

To all those interested in SQL Server 2000 tutorial in 21 days, you can access it via: http://rapidshare.com/files/35532769/SQL21days.pdf

Directive:
access the website: http://rapidshare.com/files/35532769/SQL21days.pdf
scroll down the page, click 'FREE' and On the next page enter in the higlighed letters into the box provided for the 'No Premium users'.

Wish you a successful download, 


Enjoy!!

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For we came into the world with "NOTHING", and we shall leave the world with "NOTHING"
Jojo
08037971139

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