Searching Using Keywords and Boolean Logic – Boolean Logic: Creating Effective Search Strings for Your Keywords
Boolean logic is the system of logic used by electronic search databases. It is composed of operators and connectors.
Boolean operators are used to carry out complex and specific search operations, whereas Boolean connectors are used to connect and denote relationships among multiple keywords.
Let's start with the connectors.
Boolean Connectors: Stringing Keywords Together
Boolean connectors (AND, OR, NOT) can be thought of as links used to connect multiple keywords. With connectors, you can link several keywords to create a "search-string” that will search for a combination of keywords.
The "AND” Connector
Connecting two keywords together with the word "AND” will execute a search for documents that include both keywords.
- The "AND” operator is a great way to locate documents that deal with multiple and/or related concepts!
- It is also an excellent way to narrow the scope of your search.
EXAMPLE: bankrupty AND corporation
- If you search using the keywords "bankruptcy” AND "corporation”, then only documents containing both keywords (represented by the darkened area in the Venn diagram above) will be retrieved.
NOTE: The "&” symbol may be used in place of the "AND” connector; the two are interchangeable.
The "OR” Connector:
Using the operator "OR” will retrieve documents that mention either keyword.
- The "OR” operator is great when dealing with legal concepts that can be expressed using a variety of different keywords (synonyms).
- It may also be used to broaden a keyword search if you are having difficulty locating material.
EXAMPLE: bankruptcy OR corporation
- If you search using the keywords "bankruptcy” OR "corporation”, then documents containing either keyword (represented by the darkened area in the Venn diagram above) will be retrieved.
The "NOT” Connector:
Using the operator "NOT” will exclude documents containing that keyword.
- The "NOT” operator is essential when you need to exclude documents containing a word that might commonly be associated with your topic.
- It can also be used to narrow a search if you are yielding too many unrelated results.
EXAMPLE: bankruptcy NOT corporation
- If you search using the keywords "bankruptcy” NOT "corporation”, then only documents that do not mention the word "corporation” (represented by the darkened area in the Venn diagram above) will be retrieved.