Metacat

/**

 *  '$RCSfile$'

 *    Purpose: An adapter class for Oracle RDBMS.

 *  Copyright: 2000 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Jivka Bojilova

 *

 *   '$Author: leinfelder $'

 *     '$Date: 2012-11-29 16:54:47 -0800 (Thu, 29 Nov 2012) $'

 * '$Revision: 7440 $'

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.dbadapter;

import java.sql.Connection;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

/**

 * The Oracle db adapter implementation.

 */

public class OracleAdapter extends AbstractDatabase {

  /**

   * The Oracle unique ID generator through use of sequences

   * The name of the sequence used to generate the unique id 

   * is made from the name of the table that uses the id by 

   * appending "_id_seq" to it.

   * When record is inserted in the table and insert trigger gets

   * a nextval from that sequence, select currval of that sequence

   * can return the generated key in the same db connection.

   *

   * @param conn db connection in which the unique id was generated

   * @param tableName the name of table which unique id was generate

   * @exception SQLException <br/> any SQLException that can be thrown 

   *            during the db operation

   * @return return the generated unique id as a long type

   */

  public long getUniqueID(Connection conn, String tableName) 

                                         throws SQLException {

    long uniqueid = 0;

    Statement stmt = null;

     stmt = conn.createStatement();

     stmt.execute("SELECT " + tableName + "_id_seq.currval FROM dual");

     ResultSet rs = stmt.getResultSet();

     if ( rs.next() ) {

        uniqueid = rs.getLong(1);

     }

     stmt.close();

     return uniqueid;

  }

  /**

   * The Oracle's function name that gets the current date and time

   * from the database server: "sysdate"

   *

   * @return return the current date and time function name: "sysdate"

   */

  public String getDateTimeFunction() {

    //System.out.println("The date and time function: " + "sysdate");    

    return "sysdate";

  }

  /**

   * The Oracle's function name that is used to return non-NULL value

   *

   * @return return the non-NULL function name: "nvl"

   */

  public String getIsNULLFunction() {

    return "nvl";

  }

  /**

   * The Oracles's string delimiter character: single quote (')

   *

   * @return return the string delimiter: single quote (')

   */

  public String getStringDelimiter() {

    return "'";

  }

  /**

   * The Oracles's syntax for doing a left join

   * Add 'a.' in front of the fields for first table and

   * 'b.' in front of the fields for the second table

   * 

   * @param selectFields fields that you want to be selected

   * @param tableA first table in the join

   * @param tableB second table in the join

   * @param joinCriteria the criteria based on which the join will be made

   * @param nonJoinCriteria all other criterias

   * @return return the string for teh select query

   */

  public String getLeftJoinQuery(String selectFields, String tableA, 

		  String tableB, String joinCriteria, String nonJoinCriteria){

	  return "SELECT " + selectFields + " FROM " + tableA + " a, " 

	         + tableB + " b WHERE " + joinCriteria + "(+) " + " AND (" 

	         + nonJoinCriteria +")";

  }

  /**

   * Return a hard code string to get xml_document list in timed replcation

   */

  public String getReplicationDocumentListSQL()

  {

      String sql ="select a.docid, a.rev, a.doctype from xml_documents a, xml_revisions b where a.docid=b.docid(+) and  a.rev<=b.rev(+) and b.docid is null ";

      return sql;

  }

  /**

   * @see http://www.oracle.com/technetwork/issue-archive/2006/06-sep/o56asktom-086197.html

   */

  @Override

  public String getPagedQuery(String queryWithOrderBy, Integer start, Integer count) {

	  // not limiting rows

	  StringBuffer query = new StringBuffer("SELECT " + queryWithOrderBy);

	  // check for params

	  if (start != null) {

		  query = new StringBuffer();

		  query.append("SELECT * FROM ");

		  query.append("( SELECT a.*, ROWNUM rnum FROM ");

		  query.append("( " + queryWithOrderBy + " ) a ");

		  if (count != null) {

			  // both are limited

			  query.append(" WHERE ROWNUM <= " + count);

		  }

		  query.append(" ) ");

		  query.append("WHERE rnum  >= " + start);

	  }

	  return query.toString();

  }

}