public FilterNode(Node parent) : base(parent) { }
public UnionNode(Node parent) : base(parent) { }
//Optional(n1,n2,e) => LeftJoin(n1,n2,e)
public OptionalNode(Node parent, Node child, string joinCondition) : base(parent)
{
Children.Add(child);
JoinCondition = joinCondition;
}
public ProjectNode(Node parent, List<string> projectVariable) : base(parent)
{
this.ProjectionVariables = projectVariable;
}
public JoinNode(Node parent) : base(parent) { }
public TerminalNode(Node parent, string subj, string pred, string obj) : base(parent)
{
this.Subj = subj;
this.Pred = pred;
this.Obj = obj;
}
