/**
* Redistribution and use of this software and associated documentation
* ("Software"), with or without modification, are permitted provided
* that the following conditions are met:
*
* 1. Redistributions of source code must retain copyright
* statements and notices. Redistributions must also contain a
* copy of this document.
*
* 2. Redistributions in binary form must reproduce the
* above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* 3. The name "Exolab" must not be used to endorse or promote
* products derived from this Software without prior written
* permission of Intalio, Inc. For written permission,
* please contact info@exolab.org.
*
* 4. Products derived from this Software may not be called "Exolab"
* nor may "Exolab" appear in their names without prior written
* permission of Intalio, Inc. Exolab is a registered
* trademark of Intalio, Inc.
*
* 5. Due credit should be given to the Exolab Project
* (http://www.exolab.org/).
*
* THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
* NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* INTALIO, INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Copyright 1999 (C) Intalio, Inc. All Rights Reserved.
*
* $Id$
*/
package org.castor.cpa.persistence.sql.driver;
import java.util.Enumeration;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.exolab.castor.jdo.engine.JDBCSyntax;
import org.exolab.castor.jdo.oql.SyntaxNotSupportedException;
import org.exolab.castor.persist.spi.PersistenceFactory;
/**
* QueryExpression for Oracle 7/8.
*
* As of release 8.1.6, Oracle supports limiting the number of rows returned by a query
* through the use of the following mechanism.
*
* SELECT *
* FROM (
* SELECT empno, ename, job, sal,
* rank() over (order by sal) rnk
* FROM emp
* )
* WHERE rnk BETWEEN 3 AND 8
*
* @author <a href="mailto:arkin@intalio.com">Assaf Arkin</a>
* @version $Revision$ $Date: 2005-03-24 03:45:01 -0700 (Thu, 24 Mar 2005) $
*/
public final class OracleQueryExpression extends JDBCQueryExpression {
/** The <a href="http://jakarta.apache.org/commons/logging/">Jakarta
* Commons Logging</a> instance used for all logging. */
private static Log _log = LogFactory.getFactory().getInstance(OracleQueryExpression.class);
public OracleQueryExpression(final PersistenceFactory factory) {
super(factory);
}
public String getStatement(final boolean lock) throws SyntaxNotSupportedException {
StringBuffer sql;
boolean first;
sql = new StringBuffer();
sql.append(JDBCSyntax.SELECT);
if (_distinct) {
sql.append(JDBCSyntax.DISTINCT);
}
sql.append(getColumnList());
// add support for OQL LIMIT/OFFSET - part1
if (_limit != null) {
sql.append (" , rank() over ( ");
// add ORDER BY clause
if (_order != null) {
sql.append(JDBCSyntax.ORDER_BY).append(_order);
} else {
throw new SyntaxNotSupportedException(
"To use a LIMIT clause with Oracle, an ORDER BY clause is required.");
}
sql.append(" ) rnk ");
}
sql.append(JDBCSyntax.FROM);
// Add all the tables to the FROM clause
Enumeration<String> enumeration = _tables.keys();
while (enumeration.hasMoreElements()) {
String tableAlias = enumeration.nextElement();
String tableName = _tables.get(tableAlias);
if (tableAlias.equals(tableName)) {
sql.append(_factory.quoteName(tableName));
} else {
sql.append(_factory.quoteName(tableName) + " "
+ _factory.quoteName(tableAlias));
}
if (enumeration.hasMoreElements()) {
sql.append(JDBCSyntax.TABLE_SEPARATOR);
}
}
first = true;
// Use asterisk notation to denote a left outer join
// and equals to denote an inner join
for (int i = 0; i < _joins.size(); ++i) {
Join join;
if (first) {
sql.append(JDBCSyntax.WHERE);
first = false;
} else {
sql.append(JDBCSyntax.AND);
}
join = _joins.elementAt(i);
for (int j = 0; j < join._leftColumns.length; ++j) {
if (j > 0) {
sql.append(JDBCSyntax.AND);
}
sql.append(_factory.quoteName(join._leftTable
+ JDBCSyntax.TABLE_COLUMN_SEPARATOR
+ join._leftColumns[j]));
//if ( join.outer )
// sql.append( "(+)=" );
//else
// sql.append( OpEquals );
sql.append(OP_EQUALS);
sql.append(_factory.quoteName(join._rightTable
+ JDBCSyntax.TABLE_COLUMN_SEPARATOR
+ join._rightColumns[j]));
if (join._outer) {
sql.append("(+)");
}
}
}
first = addWhereClause(sql, first);
// add ORDER BY clause, but only if no LIMIT clause has been specified
if ((_order != null) && (_limit == null)) {
sql.append(JDBCSyntax.ORDER_BY).append(_order);
}
// Use FOR UPDATE to lock selected tables.
if (lock) {
sql.append(" FOR UPDATE");
}
// add LIMIT/OFFSET clause - part 2
if (_limit != null) {
// leads to problems when used with Castor's outer joins for master-details queries:
// "ORA-00918: Spalte nicht eindeutig definiert"
sql.insert (0, "select * from ( ");
if (_offset != null) {
sql.append (" ) where rnk - " + _offset + " between 1 and " + _limit + " ");
} else {
sql.append (" ) where rnk <= " + _limit + " ");
}
}
if (_log.isDebugEnabled()) {
_log.debug ("SQL statement = " + sql.toString());
}
return sql.toString();
}
/**
* Indicates that Oracle supports an OQL LIMIT clause for versions >= 8.1.6.
*
* @return true to indicate that Oracle supports an OQL LIMIT clause.
*/
public boolean isLimitClauseSupported() {
return (_dbInfo != null) ? (_dbInfo.compareDbVersion("8.1.6") >= 0) : false;
}
/**
* Indicates that Oracle supports an OQL OFFSET clause for versions >= 8.1.6.
*
* @return true to indicate that Oracle supports an OQL OFFSET clause.
*/
public boolean isOffsetClauseSupported() {
return (_dbInfo != null) ? (_dbInfo.compareDbVersion("8.1.6") >= 0) : false;
}
}