/**
* 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.
*/
/**
* Logical (execution-engine-independent) element definitions.
*
* Drill has several representations of a query including SQL, logical plans and
* physical plans. All of the logical constructs of Drill are separated from
* their physical implementations in the Java execution engine. The components
* of this package can be used to share common logical constructs between the
* current engine and any other future alternative physical implementations of
* the same logical constructs. This is the same for the logical expression
* constructs defined within this package.
*
*/
package org.apache.drill.common;