the effect of using IT

• file


  A collection of related data stored on a lasting medium, such as a hard disk
• records

  Complete sets of information. They are compromised of fields . A file consists of a set of records.
• item


  Each piece of data inside a record
• field


  The space where items are stored
• key field


  A field in a record that uniquely identifies instances of that record
• sequential file


  a serial file in order
• serial filen


  file not sorted in particular order
• index


  indicate exactly where the record can be found
• direct access file


  file organized so that a calculation provides the address of a record so that the record can be accessed directly
• file maintenance

  1. updates and amendments2. insertions to the file3. deletions to the files
• data type


  Indicates the type of data that can be stored in the field
• numeric data types

  1. integers2. real numbers (takes up more space)
• date data type


  A data type that indicates that the data in a field represents a date eg. 07/09/12 or 07/09/2012
• alphanumeric data type


  contains mainly alphabetic and numeric characters
• Boolean data

  can be one of two possible values, True or False.
• logical data


  a data mart created by a relational view of a data warehouse
• validation check


  to make sure the data entered is validate and followed the rule
• types of validation checks

  1. length check2. character check3. format check4. presence check
• data verification

  1. compare output and original2. input data twice
• flat file

  Single table with a large number of records and fields
• secondary key


  Field by which a database is often searched
• relational tables


  when two files are related and can be referenced
• primary key

  A field (or group of fields) that uniquely identifies a given entity in a table
• foreign key


  A key in one field which appears in a field of another file
• analogue data


  A continuous varying signal, represented using an infinite number of scales. Eg - sound
• digital data


  Is text, numbers, graphics, sound, and video that has been converted into discrete digits such as 0s and 1s.
• analogue to digital converter

  A device that changes analogue signals into digital signals
• digital to analogue converter

  Converts binary words from computer into analogue signals for pixels.