ProvSQL C/C++ API
Adding support for provenance and uncertainty management to PostgreSQL databases
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Atom Struct Reference

One atom of a conjunctive query: a relation symbol applied to query variables. More...

#include "UCQJointCompiler.h"

Public Attributes

unsigned relation_id = 0
 Dense id of the relation symbol.
std::vector< unsigned > vars
 Query-variable indices, one per column.

Detailed Description

One atom of a conjunctive query: a relation symbol applied to query variables.

Constants are pre-filtered by the SQL layer (selection pushed down), so an atom mentions only variables; vars index into the disjunct's variable list. A repeated variable encodes an equality (a self-join on equal columns); two atoms may share a relation_id (a self-join).

Definition at line 65 of file UCQJointCompiler.h.

Member Data Documentation

◆ relation_id

unsigned Atom::relation_id = 0

Dense id of the relation symbol.

Definition at line 66 of file UCQJointCompiler.h.

◆ vars

std::vector<unsigned> Atom::vars

Query-variable indices, one per column.

Definition at line 67 of file UCQJointCompiler.h.

The documentation for this struct was generated from the following file: