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* 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
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* KIND, either express or implied. See the License for the
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package org.apache.cayenne.dba.postgres;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.access.DataNode;
import org.apache.cayenne.access.QueryLogger;
import org.apache.cayenne.dba.JdbcAdapter;
import org.apache.cayenne.dba.QuotingStrategy;
import org.apache.cayenne.dba.oracle.OraclePkGenerator;
import org.apache.cayenne.map.DbEntity;
import org.apache.cayenne.map.DbKeyGenerator;
/**
* Default PK generator for PostgreSQL that uses sequences for PK generation.
*/
public class PostgresPkGenerator extends OraclePkGenerator {
protected PostgresPkGenerator(JdbcAdapter adapter) {
super(adapter);
}
@Override
protected String createSequenceString(DbEntity ent) {
// note that PostgreSQL 7.4 and newer supports INCREMENT BY and START WITH
// however 7.3 doesn't like BY and WITH, so using older more neutral syntax
// that works with all tested versions.
StringBuilder buf = new StringBuilder();
buf
.append("CREATE SEQUENCE ")
.append(sequenceName(ent))
.append(" INCREMENT ")
.append(pkCacheSize(ent))
.append(" START 200");
return buf.toString();
}
/**
* @since 3.0
*/
@Override
protected long longPkFromDatabase(DataNode node, DbEntity entity) throws Exception {
DbKeyGenerator pkGenerator = entity.getPrimaryKeyGenerator();
String pkGeneratingSequenceName;
if (pkGenerator != null
&& DbKeyGenerator.ORACLE_TYPE.equals(pkGenerator.getGeneratorType())
&& pkGenerator.getGeneratorName() != null)
pkGeneratingSequenceName = pkGenerator.getGeneratorName();
else
pkGeneratingSequenceName = sequenceName(entity);
Connection con = node.getDataSource().getConnection();
try {
Statement st = con.createStatement();
try {
String sql = "SELECT nextval('" + pkGeneratingSequenceName + "')";
QueryLogger.logQuery(sql, Collections.EMPTY_LIST);
ResultSet rs = st.executeQuery(sql);
try {
// Object pk = null;
if (!rs.next()) {
throw new CayenneRuntimeException(
"Error generating pk for DbEntity " + entity.getName());
}
return rs.getLong(1);
}
finally {
rs.close();
}
}
finally {
st.close();
}
}
finally {
con.close();
}
}
/**
* Fetches a list of existing sequences that might match Cayenne generated ones.
*/
@Override
protected List<String> getExistingSequences(DataNode node) throws SQLException {
boolean status;
if (node.getDataMap(node.getName()) != null
&& node.getDataMap(node.getName()).isQuotingSQLIdentifiers()) {
status = true;
}
else {
status = false;
}
QuotingStrategy context = getAdapter().getQuotingStrategy(status);
// check existing sequences
Connection con = node.getDataSource().getConnection();
try {
Statement sel = con.createStatement();
try {
String sql = "SELECT relname FROM pg_class WHERE relkind='S'";
QueryLogger.logQuery(sql, Collections.EMPTY_LIST);
ResultSet rs = sel.executeQuery(sql);
try {
List<String> sequenceList = new ArrayList<String>();
while (rs.next()) {
sequenceList.add(context.quoteString(rs.getString(1)));
}
return sequenceList;
}
finally {
rs.close();
}
}
finally {
sel.close();
}
}
finally {
con.close();
}
}
}