Database

Database

1. Entity

   • Also known as a table
   • Attributes
     • Are the fields that make up an entity
   • A real world object

2. Boolean

   • Yes
   • No

3. Foreign Key

   • A key from another entity used to link other tables together to reduce data redundancy
     • Data redundancy - when data is no longer needed

4. Real

   • Is a decimal

5. Validation check

   • Presence check
     • Making sure that data exists
   • Range check
     • Making sure that data that is entered is between two values
   • Input mask
     • Makes sure you use the correct format of data
   • Length check
     • Making sure that the correct amount of data is typed in
   • Look up
     • A drop down list
   • Type check
     • Making sure you have used the correct data type

6. Data types

   • Integers
     • Are whole numbers
   • Strings
     • Are letters, numbers and symbols

7. DBMS

   • Database management system
   • Manage records in table
   • Run queries
     • < > And Or Not
   • Benefits
     • Set up by experts + used by end user
     • Easier to maintain/keep secure
     • Database can be accessed in many ways
     • Doesn't disrupt if one application is updated
     • Database is safe from corruption