Database

Database

1. Validation checks

   • Type check
     • Restricts the type of data the user can enter so they cant enter numbers in a sstring
   • Range check
     • Limit the range of data the user can enter by using two values for example 1-10
   • Check digits
   • Presence check
     • Checks if data has been entered in the field
   • Length check
     • It checks how long something is
   • Lookup
     • Looks up a set of data and then creates drop down boxes from that data
   • Input mask
     • Puts a mask in a field so they can only enter the data you want them to

2. Data types

   • String
     • Text, Symbols
   • Boolian
     • Yes/No True/False
   • Integer
     • Numbers
   • Real number
     • Decimals

3. Flat file vs relational

   • Flat file
     • Database that does have any keys so you cant link tables together so there is a lot of redundant data

4. Primary and foreign keys

   • Primary Key
   • Foreign key

5. Key words

   • Entity
     • A real world object for example a table in a database
   • Attributes
     • Things that make up the entity for example fields in a table

6. DBMS (Database management system)

   • Benefits
     • Easy to maintain
     • Easier to keep secure
     • Will update everything conected to it
     • Set up by experts
     • Multiple people can access
     • Can be accessed in multiple ways
       • Phone,Pc,Tablet
         • Doesn't disrupt if one app is updating