The ICT Lounge
 
Section 5.2:
Searching for Data
 

This section will take a look at the methods used to search for data that has been stored in a database.

You will learn how to use something called 'operators' which are used to structure your searches.

Key Concepts of this section:
#

#
How to use 'logical operators' to structure searches

How to use 'mathematical operators' to structure searches
What are operators?
Key Words:
Logical Operators , Mathematical Operators
# Operators are used when searching for data in a database.

# Operators are used to give the computer 'specific instructions' on what to search for.

Examples of commonly used operators:
Examples of how Operators are used within Searches

 

# Look at the table of Names, Genders and Heights below.

 

# We will use the table to show 3 examples of how logical and mathematical operators could be used to search it.

Example 1: AND with = and >
 


#
If we wanted to search the table for the following data:

 

# (Gender = Male) AND (Height is >1.7)


# The search would bring up the following result:

NOTE!
= will find an exact match.
> means 'greater than'
 
Explanation!

The search is looking for data that match BOTH parts of the criteria. For example the people in the orange cells would be returned as a result because:

 

Mike   = Male
  Height  >1.7
 

Some of the other people matched one part of the criteria but not both.

Some of the people did not match any of the criteria at all.

Example 2 : OR with = and <
 


#
If we wanted to search the table to find a different set of data such as:

 

# (Gender = Female) OR (Height is <1.7)


# The search would bring up the following result:

NOTE!
= will find an exact match.
< means 'less than'
 
Explanation!
This search is looking for data that match EITHER side of the criteria. The people in the orange cells would be returned as a result because:
Salma   = Female
  Height  <1.7
 
Robert  = Female
  Height  <1.7
 
 
Karen   = Female
  Height  <1.7
 
If EITHER side of the search is matched, the data will be returned in the result.

Example 3 : BETWEEN, AND
 


#
If we wanted to search the table to find a different set of data such as:

 

# Height BETWEEN 1.6 AND 1.7


# The search would bring up the following result:

NOTE!
Between, AND searches only work with 2 sets of numbers
 
Explanation!
This search is looking for data that lies within a range. The people in the orange cells would be returned as a result because:
Robert Height = 1.65
NOTE!
All of these heights are between 1.6 and 1.7 metres
 
Karen Height = 1.6
 
 
Frank Height = 1.7
 

   
Activity!

Click the above task and follow the instructions given on the sheet. Make sure that you complete all tasks on the sheet.