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.ambari.server.orm.helpers.dbms;
  
  import org.apache.ambari.server.orm.DBAccessor;
  import org.eclipse.persistence.platform.database.DatabasePlatform;
  
  public class DerbyHelper extends GenericDbmsHelper {
    public DerbyHelper(DatabasePlatform databasePlatform) {
      super(databasePlatform);
    }
  
    @Override
    public boolean supportsColumnTypeChange() {
      return false; //type change is dramatically limited to varchar length increase only, almost useless
    }
  
    @Override
    public String getRenameColumnStatement(String tableName, String oldName, DBAccessor.DBColumnInfo columnInfo) {
      StringBuilder builder = new StringBuilder();
  
      builder.append("RENAME COLUMN ").append(tableName).append(".").append(oldName);
      builder.append(" TO ").append(columnInfo.getName());
  
      return builder.toString();
    }
  
    @Override
    public StringBuilder writeColumnModifyString(StringBuilder builder, DBAccessor.DBColumnInfo columnInfo) {
      builder.append(" ALTER COLUMN ").append(columnInfo.getName())
        .append(" SET DATA TYPE ");
      writeColumnType(builder, columnInfo);
  
      return builder;
    }
  
    @Override
    public StringBuilder writeSetNullableString(StringBuilder builder,
        String tableName, DBAccessor.DBColumnInfo columnInfo, boolean nullable) {
      builder.append(" ALTER COLUMN ").append(columnInfo.getName());
      String nullStatement = nullable ? " NULL" : " NOT NULL";
      builder.append(nullStatement);
      return builder;
    }
  
    @Override
    public String writeGetTableConstraints(String databaseName, String tableName){
      StringBuilder statement = new StringBuilder()
        .append("SELECT")
          .append(" C.CONSTRAINTNAME AS CONSTRAINT_NAME,")
          .append(" C.TYPE AS CONSTRAINT_TYPE")
        .append(" FROM SYS.SYSCONSTRAINTS AS C, SYS.SYSTABLES AS T")
        .append(" WHERE C.TABLEID = T.TABLEID AND T.TABLENAME = '").append(tableName).append("'");
      return statement.toString();
    }
  }
  