2.2.3(c) Records

Question 1

records stored in text files = (6 things)

Answer 1

• stored on secondary storage
• used to store data when the application is closed
• useful for small volumes of data eg.configuration files
• each entry is stored on a new line or separated with an identifier such as a comma or tab
• can require a linear search to find/read data which is slow (if there is no order to data or record structure)
• structured text files eg. CSV, XML & JSON are popular for storing and exchange data between applications

Question 2

records stored in arrays and lists (6 things)

Answer 2

• stored in RAM
• used to store data when a program is running
• useful for small volumes or data an algorithm is using
• can be single or multi-dimensional allowing for table of data to be stored
• uses indexes to refer to data items
• efficiency algorithms or linear searches can be used to find data

Question 3

records stored in databases (7 things)

Answer 3

• often stored on remote servers
• often used to store data shared by many users eg. ticket booking system
• data is stored in records and fields
• uses advanced data structures to store data efficiently
• uses very efficient algorithms to search and sort data executed on the servers
• more secure than text files
• the order of fields in database in independent of the code

Question 4

record structure (5 things)

Answer 4

• a collection of related fields
• a field is a variable
• each field in a record can have a different data type
• there are 3 steps in making use of record structures:
  
  • what fields will be in the record
  • declare a variable or array to use with the record structure
  • assign and retrieve data from the variable record
• be careful to note the dot syntax when using records : records<dot> field eg.car1.Make</dot>