DataBases

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Backups and recovery

Szerző: Liam LeCarpentier

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Szerző: Kyriacos Vidalakis

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Szerző: Monica Bramall

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Szerző: Wisarut Ruangwohan

DataBases

Relationship types

Many to Many

One to Many

One to one

Data Types

Currency

Data is stored in a curtain format so is shown properly

Date/Time

Only Date or time can be entered into this data type

Boolean

The only data that can be stored here is YES or NO

Number

The user can only enter a number (if the number starts with a "0" the Zero is removed, if the number starts with a zero it is best to use Text instead.

Text

Can enter a number, or characters (this includes Special Characters)

Unique Identifier

The unique number given to each Record in the File

DataBase storage types

Relational DataBase

makes use of multipule files, and linked together using relationship Keys

> easy to find Data

> Data is hard to repeat

>

Flat File Database

This DataBase type makes use of a single file to store all data entered.

Disadvantages

> Data will be repeated

> Information can be incorrectly entered

> single use

> Hard to understand

Advantages

> Fast to set up

> all in one place