Boolean or logical operators are used to establish relationships between the various terms.
- AND: both terms must occur (this corresponds to a narrowing of the search)
- OR: one of two terms should occur (this corresponds to a broadening of the search)
- NOT: the term must not occur (this corresponds to EXCEPT FOR).
The following symbols are used with some databases:
+ (a plus sign) for AND
, (a comma) for OR
- (a minus sign) for NOT
Searching for labour market OR careers produces publications that contain references only to the labour market, only to careers or to both labour market and careers.
Searching for labour market AND careers produces publications that contain references to both labour market and careers.
Searching for labour market NOT careers produces publications that contain references to the labour market but not to careers.
Example of Boolean operator AND
Example of Boolean operator OR
Example of Boolean operator NOT
Example: With the use of different operators in a single search assignment, you should make allowances for the fact that AND and NOT should both precede OR, so that you may have to add brackets and/or quotation marks.
Tip: Be careful when using the NOT operator; it is easy to exclude too much information. Also, records that contain both elements will be excluded. The NOT combination is quite suitable for excluding records that have already been reviewed from a previous search: for example, #8 NOT #4