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Database Theory Each Table in a Database needs a Primary Key Data TypesDescriptionExample TextCharacters (Letters, numbers and symbols) ABC 123 NumberNumerical.

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Presentation on theme: "Database Theory Each Table in a Database needs a Primary Key Data TypesDescriptionExample TextCharacters (Letters, numbers and symbols) ABC 123 NumberNumerical."— Presentation transcript:

1 Database Theory Each Table in a Database needs a Primary Key Data TypesDescriptionExample TextCharacters (Letters, numbers and symbols) ABC 123 NumberNumerical Value1.4 Date/timeDates and times01/01/ :45 BooleanYes/No, also known as True/False YES Data types used in a database (how data is stored) Table(A Set of Data) Record(A Row of information in a Table) Fields (e.g. Gender, Name, DOB)

2 Each Table in a Database needs a Primary Key A Primary Key uniquely identifies a record (Row of Data) Customer Customer ID Name Address DOB Order Order ID Date Price Paid Customer ID Primary Key Table Name One to Many Relationship There can be many Customers who make Orders Foreign Key A Primary key in another table this creates a Relationship Primary Keys Relationships Foreign Keys

3 Database in Practice Online A Database can be Local or Search engines use Databases to store information DBMS Database Management Systems Allows you to use your own databases Sets different levels of access by user SQL Structured Query Language Language used to create Databases 2 parts DDL (Data Definition Language)-defines Structure. DML (Data Manipulation Language)-Makes changes ((Add,Delete,Edit)

4 Why use databases Easy to find specific data Electronic data more secure than paper Examples of Online databases Online databases use the internet to share access to it form all around the world. Social Media uses Databases e.g. Facebook, Amazon Social Media uses Databases e.g. Facebook, Amazon A Local database is Stored and accessed on it’s own network More Secure than Online Databases


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