Database Search Tips: Boolean operators

The purple triangle in the middle of the lower Venn diagram shows the result set of this search. This is a small collection using AND combining all three search terms.

All search terms are included in the search results, but they may not be connected together as you wish

For example, the following search: college stud's test anxiety will be converted to university and student and exam and anxiety. Words may appear separately in result record

For example, "college student" or "test unrest". In this way, the phrase will appear in the results you expect.

Expand the results and tell the database that one of the search records is likely to appear in the results record.

All three circles represent the result set of this search. This is a large collection, as these words are all valid using the OR operator.

The database follows the commands entered and returns results based on those commands. When using Boolean operators, be aware of the logical order of word bindings.

A database usually recognizes AND as the main operator and concatenates concepts with AND first.

If you use a combination of AND and OR operators for search, enclose the word in parentheses with "ORed".

Boolean (or logical) operators are connectors that establish relationships between search terms. They tell the database how to search and execute the keywords. The name "Boolean" was regarded as the founder of a logical algebra after the 19th century British mathematician George Boole. The most common logical operators are AND, OR, NOT. The result includes the term "crime" or the term "theft", or two terms. If you use the Boolean operator "OR", at least one term is displayed for all results. In the search, arbitrary terms in arbitrary places in the project are searched in an arbitrary order. You can connect other similar terms using the logical operator "OR" to specify database options and continue to add equivalent terms connected with "OR".

One way to restrict database search with Boolean operators is to use a boolean operator; you can narrow or extend the search results by adding words to the search results. They are, and are not. Usually these words are in the Advanced Search Query area of ​​the database. Then narrow the search range. For example, if you are interested in freshwater fishing, you can enter the word "fish and freshwater". The result contains records that contain only these two words. Let's go back to Sally and search the GEORef database. If she remembers, she looked for a controlled vocabulary "hydraulic crush". She can focus and limit her results using the phrase "Mar - cellus Shale". Sally's search query has become "hydraulic fracturing and Marcellus Shale". You can see this below. The overlap region indicates the record that this retrieval retrieves

Boolean search. For example, you can search for the word "Coase" before the word "theorem" and get all instances of the phrase "Coase theorem" in a particular database. The logical operators "AND", "OR", and "NOT" can be used in the same way as proximity variables like "Theorem" of "Coase" represented by two words. Boolean search is powerful. However, the worlds of Westlaw and Lexis-Nexis are not infamous because these databases are unique and closed down. They are proprietary - access to search engines is expensive. They are closed - databases can not be retrieved by Internet search engines like Google. In other words, only a small percentage of global scholars and students can access these systems. Of course it is important to have access to it - it includes most law scholars from the North Atlantic and Commonwealth countries. However, excluded groups of scholars are huge.