Java tutorial
/***************************************************************** * 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.cayenne.dbsync.reverse.dbload; import java.sql.DatabaseMetaData; import java.sql.ResultSet; import java.sql.SQLException; import org.apache.cayenne.map.DbAttribute; import org.apache.cayenne.map.DbEntity; import org.apache.cayenne.map.DetectedDbEntity; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; class PrimaryKeyLoader extends PerEntityLoader { private static final Log LOGGER = LogFactory.getLog(DbLoader.class); PrimaryKeyLoader(DbLoaderConfiguration config, DbLoaderDelegate delegate) { super(null, config, delegate); } @Override ResultSet getResultSet(DbEntity dbEntity, DatabaseMetaData metaData) throws SQLException { return metaData.getPrimaryKeys(dbEntity.getCatalog(), dbEntity.getSchema(), dbEntity.getName()); } @Override void processResultSet(DbEntity dbEntity, DbLoadDataStore map, ResultSet rs) throws SQLException { String columnName = rs.getString("COLUMN_NAME"); DbAttribute attribute = dbEntity.getAttribute(columnName); if (attribute == null) { // why an attribute might be null is not quiet clear // but there is a bug report 731406 indicating that it is // possible so just print the warning, and ignore LOGGER.warn("Can't locate attribute for primary key: " + columnName); return; } attribute.setPrimaryKey(true); ((DetectedDbEntity) dbEntity).setPrimaryKeyName(rs.getString("PK_NAME")); } }