Conjunctive queries problems

  • What is conjunction in database?

    In database theory, a conjunctive query is a restricted form of first-order queries using the logical conjunction operator.
    Many first-order queries can be written as conjunctive queries.
    In particular, a large part of queries issued on relational databases can be expressed in this way..

  • What is conjunctive selection in DBMS?

    Conjunctive selection using an individual index: If an attribute involved in any single simple condition in the conjunctive condition has an access path that permits the use of one of the methods S2 to S6 to retrieve the records and then check whether each retrieved record satisfies the remaining conditions in the .

Jun 18, 2023The fitting problem for conjunctive queries (CQs) is the problem to construct a CQ that fits a given set of labeled data examples.
In database theory, a conjunctive query is a restricted form of first-order queries using the logical conjunction operator. Many first-order queries can be 
The fitting problem for conjunctive queries (CQs) is the problem to construct a CQ that fits a given set of labeled data examples. When a fitting CQ exists, it is in general not unique.

What is a conjunctive query?

In database theory, a conjunctive query is a restricted form of first-order queries using the logical conjunction operator.
Many first-order queries can be written as conjunctive queries.
In particular, a large part of queries issued on relational databases can be expressed in this way.

,

What is the computational complexity of evaluating conjunctive queries?

For the study of the computational complexity of evaluating conjunctive queries, two problems have to be distinguished.
The first is the problem of evaluating a conjunctive query on a relational database where both the query and the database are considered part of the input.

,

What is the query containment problem for conjunctive queries with inequalities?

Example:

  • Q(x
  • y):-- E(x
  • z)
  • E(z
  • w)
  • E(w
  • y)
  • z ≠ w
  • z < y.
    The query containment problem for conjunctive queries with inequalities is Π2 p-complete.
    The query evaluation problem for conjunctive queries with inequalities in NP-complete.
    Monotone Queries/ Conj.Queries with Inequal.

    • Categories

    Conjunctive queries inclusion dependencies
    Graphical conjunctive queries
    Inference conjunctive queries
    Join conjunctive queries
    Union of conjunctive queries
    Equivalence of conjunctive queries
    Evaluation of conjunctive queries
    Theory of conjunctive queries
    Conjunctive queries equality
    Conjunctive query answering
    Conjunctive query algorithm
    Conjunctive conjunction examples
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    Ovsdb-client query example
    Conjunctive queries
    Conjunctive query containment
    Conjunctive query combine complexity
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