Information Systems Flashcards
What is a database
Collection structured of similar information that can be accessed easily
What is data
It is raw, unprocessed information, doesn’t mean anything by itself
What is information
It is data which is processed to give it a meaning
What takes up more space - manual or electronic database
Manual
Which can be searched quickly - manual or electronic database
Electronic
Which is most expensive to set up - manual or electronic database
Manual
Which is most secure - manual or electronic database
Electronic
What does a database management system do
It’s a program that stores data
What are the main operations that a DBMS carries out?
Editing, sorting, searching, extracting
How is the data structures in a DBMS
Into files, records and fields
What is a file
Collection of similar data
What is a record
contains all the data about one particular person or object.
What is a field
name given to each separate item of data which is contained within the record
What are the data types in a database
Text, integer, real number, Boolean, decimal, currency, date, time
What is an advantage of using a computerised database
Calculated fields can be created
What is a primary key
To distinguish between records that have duplicate information we must specify one key as a primary key
Field that has a unique entry for every record
What is data validation
Checking if the entered data is sensible and allowable
How can you validate data?
Presence check - checking that you haven’t left an important field blank
Restricted choice - only allows user to choose from a list of valid values
Length check - only allows a specific amount of characters to be entered
Range check - allows data within a specific range
What is one of the most powerful tools in a database
Is the ability that the program has to search through vast quantities of information
What are types of searches
Simple search - search on one piece of criteria
Complex search - search on more than one criteria
What is a flat file system
It is a table that contains all the data
When can a flat file system be useful
When there is not a lot of data
What are the disadvantages to using a flat file system
There might be duplication of data
If data is duplicated then there is inconsistency in the data
Insertion problems - data has to be included more than necessary
Deletion problems - if single record is deleted then it may remove important data
How can the disadvantage of a flat file system be overcome?
By storing the data in a relational database
