/*
* Copyright 2004-2023 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.index;
import org.h2.command.query.AllColumnsForPlan;
import org.h2.engine.SessionLocal;
import org.h2.result.Row;
import org.h2.result.SearchRow;
import org.h2.result.SortOrder;
import org.h2.table.DualTable;
import org.h2.table.IndexColumn;
import org.h2.table.TableFilter;
import org.h2.value.Value;
/**
* An index for the DUAL table.
*/
public class DualIndex extends VirtualTableIndex {
public DualIndex(DualTable table) {
super(table, "DUAL_INDEX", new IndexColumn[0]);
}
@Override
public Cursor find(SessionLocal session, SearchRow first, SearchRow last) {
return new DualCursor();
}
@Override
public double getCost(SessionLocal session, int[] masks, TableFilter[] filters, int filter, SortOrder sortOrder,
AllColumnsForPlan allColumnsSet) {
return 1d;
}
@Override
public String getCreateSQL() {
return null;
}
@Override
public boolean canGetFirstOrLast() {
return true;
}
@Override
public Cursor findFirstOrLast(SessionLocal session, boolean first) {
return new SingleRowCursor(Row.get(Value.EMPTY_VALUES, 1));
}
@Override
public String getPlanSQL() {
return "dual index";
}
}