Turtle DB
A mini DDBMS
ca.uqac.dim.ddb.Projection Class Reference
Inheritance diagram for ca.uqac.dim.ddb.Projection:
ca.uqac.dim.ddb.UnaryRelation ca.uqac.dim.ddb.Relation

List of all members.

Public Member Functions

 Projection (Schema sch, Relation rel)
Schema getSchema ()
void setSchema (Schema sch)
void accept (QueryVisitor v) throws QueryVisitor.VisitorException

Protected Member Functions

Tuple internalNext ()

Protected Attributes

Schema m_schema

Constructor & Destructor Documentation


Member Function Documentation

void ca.uqac.dim.ddb.Projection.accept ( QueryVisitor  v) throws QueryVisitor.VisitorException [virtual]

Returns the relation's schema

Returns:
The schema

Implements ca.uqac.dim.ddb.Relation.

Method that must be implemented by every non-abstract relation; it returns the next tuple of the enumeration, if any. Methods next and hasNext use the return value of internalNext and additionally remove any duplicate tuples from the output enumeration. Hence a call to next may result in multiple calls to the relation's internalNext, if the tuples returned are already part of the result (this is especially true of Projections.

Returns:
The next tuple, null if no such tuple exists

Implements ca.uqac.dim.ddb.Relation.


Member Data Documentation


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