/**
 * Copyright 2011-2013 Akiban Technologies, Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* The original from which this derives bore the following: */

/*

   Derby - Class org.apache.derby.impl.sql.compile.DMLStatementNode

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to you under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */

package com.akiban.sql.parser;

import com.akiban.sql.StandardException;

/**
 * A DMLStatementNode represents any type of DML statement: a cursor declaration,
 * an INSERT statement, and UPDATE statement, or a DELETE statement.    All DML
 * statements have result sets, but they do different things with them.  A
 * SELECT statement sends its result set to the client, an INSERT statement
 * inserts its result set into a table, a DELETE statement deletes from a
 * table the rows corresponding to the rows in its result set, and an UPDATE
 * statement updates the rows in a base table corresponding to the rows in its
 * result set.
 *
 */

public abstract class DMLStatementNode extends StatementNode
{
    /**
     * The result set is the rows that result from running the
     * statement.    What this means for SELECT statements is fairly obvious.
     * For a DELETE, there is one result column representing the
     * key of the row to be deleted (most likely, the location of the
     * row in the underlying heap).  For an UPDATE, the row consists of
     * the key of the row to be updated plus the updated columns.    For
     * an INSERT, the row consists of the new column values to be
     * inserted, with no key (the system generates a key).
     *
     * The parser doesn't know anything about keys, so the columns
     * representing the keys will be added after parsing (perhaps in
     * the binding phase?).
     *
     */
    private ResultSetNode resultSet;

    /**
     * Initializer for a DMLStatementNode
     *
     * @param resultSet A ResultSetNode for the result set of the
     *                                  DML statement
     */

    public void init(Object resultSet) {
        this.resultSet = (ResultSetNode)resultSet;
    }

    /**
     * Fill this node with a deep copy of the given node.
     */
    public void copyFrom(QueryTreeNode node) throws StandardException {
        super.copyFrom(node);

        DMLStatementNode other = (DMLStatementNode)node;
        this.resultSet = (ResultSetNode)getNodeFactory().copyNode(other.resultSet,
                                                                  getParserContext());
    }

    /**
     * Prints the sub-nodes of this object.  See QueryTreeNode.java for
     * how tree printing is supposed to work.
     *
     * @param depth The depth of this node in the tree
     */

    public void printSubNodes(int depth) {
        if (resultSet != null) {
            printLabel(depth, "resultSet: ");
            resultSet.treePrint(depth + 1);
        }
    }

    /**
     * Get the ResultSetNode from this DML Statement.
     * (Useful for view resolution after parsing the view definition.)
     *
     * @return ResultSetNode The ResultSetNode from this DMLStatementNode.
     */
    public ResultSetNode getResultSetNode() {
        return resultSet;
    }

    /**
     * Accept the visitor for all visitable children of this node.
     * 
     * @param v the visitor
     *
     * @exception StandardException on error
     */
    void acceptChildren(Visitor v) throws StandardException {
        super.acceptChildren(v);

        if (resultSet != null) {
            resultSet = (ResultSetNode)resultSet.accept(v);
        }
    }

}