All four concepts are expected to be present. Boolean operators can be graphically demonstrated by the Venn diagram of two slightly overlapping circles. The researcher who realizes this can build a more effective search. Consulting either librarians or database help screens can often shed light on the question of whether and how Boolean operators can be used in the database at hand. This feature is particularly useful when the database implicitly performs a Boolean operation between words.
Some databases create phrase searching by placing parentheses around the terms.
Internet search engines signify phrase searching by enclosing the terms with quotation marks. Again, help screens or librarians can provide guidance on constructing a phrase search. This feature allows the searcher to pull together into one group all words that begin with or contain the same word root. Different databases may use different symbols to indicate truncation. Again, consulting a librarian or the database help screens may help.