Flat files, relational databases

• single table of data
• table not connected to anything else
• used to store lists
• easy to create
• contains a lot of duplicate data
• problems due to duplicate data:

     - file size large, storage space is wasted, slow to retrieve data

    - easy to create errors when entering data

• when 2 or more flat files are combined
• tables are liked with foreign keys and relationships

advantages

• data consistancy- each data item is only stored once, no danger of data being updated in one place and not the other
• time saved on entering data as data doesn't need to entered repeatidly
• data redundancy- no data is unecessarily replicated  so no storage space is wasted
• uses a databse management system (DBMS) which controls the access to different parts of the database son only certain users can access it.
• DBMS uses referential integrity- set of rules applyed to data to prevent you from entering inconsistant data

disadvantages

• setting up and maintaining relational databases is complex and time comsuming
• complex software needed to set up and maintain databse
• expertise needed to carry out effective design, creation and maintenance