It is possible to compose some complex search expressions using Boolean logic on this search system. To do so, use the following terms: AND OR & NOT

Boolean logic provides a simple and elegant way to construct a "search expression" with which to find precisely the information you need

How Boolean logic works is represented by the following diagrams:

AND narrows your search

This is expressed as light green AND dark green

When using AND the results retrieved will contain both light and dark green information. The results will not include those documents containing only light green or only dark green information. In the diagram the documents retrieved by using this search expression are contained within the middle green area. For example a search for Urban AND Greenspaces will retrieve only those records containing both keywords.

This is expressed as light green OR dark green

When using OR the results retrieved will contain either light green information, or dark green information, or light and dark green information together (middle green) In the diagram the documents retrieved by using this search expression are contained within all the colour areas. For example parks or gardens. For example a search for Parks OR Gardens will retrieve all records containing the keywords parks or gardens in addition to those containing both

NOT removes unwanted records from your search

This is expressed as dark green NOT light green

When using NOT results will contain only dark green. The NOT operator will exclude light green completely and any oher shade of green information will also be eliminated. The NOT operator should be used carefully as it can exclude some potentially useful infomation. For example if you typed theme Parks NOT Disney in order to elminate all the Walt Disney themeparks you would retrieve all records containing the phrase theme park but none containing the word Disney. You could a useful book that was on theme parks that are not Walt Disney Parks because the autho'rs name happened to be Joanne Disney.