Boolean conjunctive query: Difference between revisions

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As an example, if a [[database schema]] contains the relation symbols {{mvar|Father}} (binary, who's the father of whom) and {{mvar|Employed}} (unary, who is employed), a conjunctive query could be <math>Father(\text{Mark}, x) \wedge Employed(x)</math>. This query evaluates to true if there exists an individual {{mvar|x}} who is a child of Mark and employed. In other words, this query expresses the question: "does Mark have an employed child?"
 
== Complexity ==
 
{{Main|Conjunctive query#Complexity}}
 
==See also==