content: /*
   * 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 org.apache.calcite.schema;
  
  import org.apache.calcite.plan.RelOptTable;
  
  /** Describes how a column gets populated.
   *
   * @see org.apache.calcite.sql2rel.InitializerExpressionFactory#generationStrategy
   * @see RelOptTable#getColumnStrategies()
   */
  public enum ColumnStrategy {
    /** Column does not have a default value, but does allow null values.
     * If you don't specify it in an INSERT, it will get a NULL value. */
    NULLABLE,
    /** Column does not have a default value, and does not allow nulls.
     * You must specify it in an INSERT. */
    NOT_NULLABLE,
    /** Column has a default value.
     * If you don't specify it in an INSERT, it will get a NULL value. */
    DEFAULT,
    /** Column is computed and stored. You cannot insert into it. */
    STORED,
    /** Column is computed and not stored. You cannot insert into it. */
    VIRTUAL;
  
    /**
     * Returns whether you can insert into the column.
     *
     * @return true if this column can be inserted
     */
    public boolean canInsertInto() {
      return this != STORED && this != VIRTUAL;
    }
  }
  