Databases

Databases

1. The term database is meant: A STRUCTURED SET OF DATA HELD IN A COMPUTER ESPECIALLY ONE THAT IS ACCESSIBLE IN VARIOuS WAYS

   • EXAMPLES OF DATA BASES ARE USED
     • HOSPITALS-medical records, patients allergy
     • Schools-Names of students ,parents/guardians
     • Banks- Addresses, money, names, incomes
     • ICLOUD- photos, Music, contacts
     • OPTICIANS-Names, addresses,prescriptions,card details

2. Structure of a database

   • A record; is a record of information that can be stored in the database
   • A field: is a category, things can be searched for

3. BENEFITS OF PAPER BASE DATABASE

   • DOESN'T REQUIRE ANY INTERNET OR WITH OUT A COMPUTER
   • THE LAYOUT IS FIXED
   • EASY TO SEARCH IN TIME FOR EMERGENCIES
   • DIFFICULT TO SEARCH THROUGH FIELDS
   • You only have one primary key

4. Benefits of Computer base database

   • Things can be searched for in any field quickly
   • Easily able to insert and delete records
   • Layout is easily altered
   • Can be accessed by more than one at a time

5. Entity: a real world object In a database, anything about which information can be stored; for example, a person, concept, physical object or event. Typically refers to a record structure.

6. DATABASE MANAGEMENT SYSTEM: A software used to create,edit and search through a database

   • A DMS:provides a standard way to create a database
   • It provides a level of security so only authourised people can access
   • Examples: Access, SQL, Oracal

7. Problems with Paperbase database

   • Takes up space
   • Can be problematic
     • Leads to data redundancy
       • DATA REDUNDANCY: When deatils need to be entered again
   • Takes time to enter all the data again

8. Validation

   • Helps the process by checking to see if the data being entered is senstivie and valid and in the correct format
   • Types of validation.
     • Presence Check
       • Is the simplest form of all validation. Simply checks to see if the data is being entered into a field. Often these fields have an aesterix showing they are required and are highlighted if they are left blank
     • Data Check
       • The field is often a calendar to make sure a valid date is selected. It ensured that it shows the correct year
     • Range Check
       • This validation ensures that numerical data is between a particular range
     • Length Check
       • Checks to see if the length of data is available
         • Example: Mobile Phone numbers, ISBn numbers, if the data is too long or too short it will appear invalid
     • Format Check
       • Some fields require data to be in a particular format. Some product codes may need to have a combination of letters and numbers in a certain pattern
     • Look up check
       • Looks up the data to make sure it exists
       • Example: Car registrations
     • Check Digit
       • Some numbers end in a number that is calculated from previous numbers.
       • Examples: Credit card numbers, ISBN numbers. If any number is incorrect the check digit calculated will not match the one entered
   • Validation is only as good as the data you enter