Database Hierachy9ISTT3L3 - Information Software Technology

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Components of a Database

•A database has components to store individual FACTS (data) in an organised way

•data is the building blocks of information•organising data (facts) in a certain way

produces information•The way this is done forms a HIERARCHY

DatabaseFILE

Record Record

Field Field Field Field

DataData DataData DataData DataData

Hierachy of a Database

•1. The TABLE - Student Details.•2. The RECORD - a complete set of

data for a student that is ORGANISED•3. The FIELDS - the individual ‘cells’ or

FACTS or data that when ORGANISED and put together form a RECORD

•DATA (facts) - The characters or details in each FIELD

Characters•Characters can be letters, numbers

or symbols - stored in a FIELD•These characters are the data/facts•REMEMBER - all data is ultimately

processed by a computer in BINARY form, so video/sound/images are all turned into characters for the purpose of data-storage.

DBMS•In order to work with data and

DATABASES we use a DBMS•This means DATABASE

MANAGEMENT SYSTEM•The DBMS has tools in it that allow

humans to configure, manage, enter, manipulate and process the data.

FLAT FILE database

•A FILE that is contains one TABLE where all the records are stored together is called a FLAT FILE DATABASE

•It is the simplest form of database

RELATIONAL Database

•When a database has many tables of data we often ask questions that require the DBMS to QUERY several tables.

•For example : I have a table for names and addresses and another table that contains a list of videos I own.

• If I lend a video to a friend, to record it in a Database I would need to RELATE the name table to the video table

Design a database•Consider what FIELDS you would need

to keep RECORDS for friends names and addresses

•Consider what FIELDS you would need to keep RECORDS of videos you own (so that you have some info about them)

•What FIELDS/INFORMATION would you need if you wanted to keep a RECORD of who you have lent your videos to.

RELATED tables•Because you will need THREE tables

to do this, each table has a RELATIONSHIP to each other.

•Using a RELATIONAL database means you dont need to duplicate FIELDS and information ... the are the most common form of DATABASE

Borrower Table

Address Table Video Table