PATTERN MATCHING QUERIES

• It is also called "Fuzzy Query".

• You can enter "ungrammatical sentences", "incomplete sentence fragments", "disjoint phrases", "nonsense words".

• The search engine get the collection of keywords.

• Required keyword: Mark with "+" before the keyword.

• Prohibited keyword: Mark with "-" before the keyword.

BOOLEAN QUERIES

• A Boolean Query is a query that consists keywords but with logical operators (AND, OR, NOT).

• X AND Y - will return URLs that contain both X and Y.

• X OR Y - will return URLs that contain either X or Y.

• X AND NOT Y - will return URLs that contain X and do not contain Y.

• Symbol: AND-&, OR-I, NOT-I, NEAR-~.