diff -r 7e08730da258 -r 4a1864c3e867 java/sql-dk/src/main/java/info/globalcode/sql/dk/DatabaseConnection.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/java/sql-dk/src/main/java/info/globalcode/sql/dk/DatabaseConnection.java	Mon Mar 04 20:15:24 2019 +0100
@@ -0,0 +1,192 @@
+/**
+ * SQL-DK
+ * Copyright © 2013 František Kučera (frantovo.cz)
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+package info.globalcode.sql.dk;
+
+import static info.globalcode.sql.dk.jmx.ConnectionManagement.incrementCounter;
+import static info.globalcode.sql.dk.jmx.ConnectionManagement.resetCounter;
+import info.globalcode.sql.dk.batch.Batch;
+import info.globalcode.sql.dk.batch.BatchException;
+import info.globalcode.sql.dk.configuration.DatabaseDefinition;
+import info.globalcode.sql.dk.configuration.Loader;
+import info.globalcode.sql.dk.configuration.Properties;
+import info.globalcode.sql.dk.formatting.ColumnsHeader;
+import info.globalcode.sql.dk.formatting.Formatter;
+import info.globalcode.sql.dk.jmx.ConnectionManagement;
+import info.globalcode.sql.dk.jmx.ConnectionManagement.COUNTER;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.SQLWarning;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Represents connected database. Is derived from {@linkplain DatabaseDefinition}.
+ * Wraps {@linkplain Connection}.
+ *
+ * Is responsible for executing {@linkplain SQLCommand} and passing results to the
+ * {@linkplain Formatter}.
+ *
+ * @author Ing. František Kučera (frantovo.cz)
+ */
+public class DatabaseConnection implements AutoCloseable {
+
+	private static final Logger log = Logger.getLogger(DatabaseConnection.class.getName());
+	public static final String JDBC_PROPERTY_USER = "user";
+	public static final String JDBC_PROPERTY_PASSWORD = "password";
+	private final DatabaseDefinition databaseDefinition;
+	private final Connection connection;
+	private final Properties properties;
+	/**
+	 * Could be null = JMX is disabled → must check, see functions in
+	 * {@linkplain ConnectionManagement}
+	 */
+	private final ConnectionManagement connectionMBean;
+
+	/**
+	 *
+	 * @param databaseDefinition DB url, name, password etc.
+	 * @param properties additional properties from CLI
+	 * @param connectionMBean JMX management bean | null = disabled JMX reporting
+	 * @throws SQLException
+	 */
+	public DatabaseConnection(DatabaseDefinition databaseDefinition, Properties properties, ConnectionManagement connectionMBean) throws SQLException {
+		this.databaseDefinition = databaseDefinition;
+		this.properties = properties;
+		this.connectionMBean = connectionMBean;
+		this.connection = Loader.jdbcConnect(databaseDefinition, properties);
+	}
+
+	public void executeQuery(SQLCommand sqlCommand, Formatter formatter) throws SQLException {
+		formatter.writeStartBatch();
+		formatter.writeStartDatabase(databaseDefinition);
+		formatter.writeStartStatement();
+		formatter.writeQuery(sqlCommand.getQuery());
+		formatter.writeParameters(sqlCommand.getParameters());
+		processCommand(sqlCommand, formatter);
+		formatter.writeEndStatement();
+		formatter.writeEndDatabase();
+		formatter.writeEndBatch();
+	}
+
+	public void executeBatch(Batch batch, Formatter formatter) throws SQLException, BatchException {
+		formatter.writeStartBatch();
+		formatter.writeStartDatabase(databaseDefinition);
+		while (batch.hasNext()) {
+			SQLCommand sqlCommand = batch.next();
+			formatter.writeStartStatement();
+			formatter.writeQuery(sqlCommand.getQuery());
+			formatter.writeParameters(sqlCommand.getParameters());
+			processCommand(sqlCommand, formatter);
+			formatter.writeEndStatement();
+		}
+		formatter.writeEndDatabase();
+		formatter.writeEndBatch();
+	}
+
+	private void processCommand(SQLCommand sqlCommand, Formatter formatter) throws SQLException {
+		incrementCounter(connectionMBean, COUNTER.COMMAND);
+		resetCounter(connectionMBean, COUNTER.RECORD_CURRENT);
+
+		try (PreparedStatement ps = sqlCommand.prepareStatement(connection)) {
+			log.log(Level.FINE, "Statement prepared");
+			sqlCommand.parametrize(ps);
+
+			boolean isRS = ps.execute();
+			log.log(Level.FINE, "Statement executed");
+			if (isRS) {
+				try (ResultSet rs = ps.getResultSet()) {
+					processResultSet(rs, formatter);
+				}
+			} else {
+				processUpdateResult(ps, formatter);
+			}
+			logWarnings(ps);
+
+			while (ps.getMoreResults() || ps.getUpdateCount() > -1) {
+				ResultSet rs = ps.getResultSet();
+				if (rs == null) {
+					processUpdateResult(ps, formatter);
+				} else {
+					processResultSet(rs, formatter);
+					rs.close();
+				}
+				logWarnings(ps);
+			}
+		}
+	}
+
+	private void processUpdateResult(PreparedStatement ps, Formatter formatter) throws SQLException {
+		formatter.writeUpdatesResult(ps.getUpdateCount());
+	}
+
+	private void processResultSet(ResultSet rs, Formatter formatter) throws SQLException {
+		formatter.writeStartResultSet(new ColumnsHeader(rs.getMetaData()));
+
+		int columnCount = rs.getMetaData().getColumnCount();
+
+		while (rs.next()) {
+			incrementCounter(connectionMBean, COUNTER.RECORD_CURRENT);
+			incrementCounter(connectionMBean, COUNTER.RECORD_TOTAL);
+
+			formatter.writeStartRow();
+
+			for (int i = 1; i <= columnCount; i++) {
+				formatter.writeColumnValue(rs.getObject(i));
+			}
+
+			formatter.writeEndRow();
+		}
+
+		formatter.writeEndResultSet();
+	}
+
+	private void logWarnings(PreparedStatement ps) throws SQLException {
+		SQLWarning w = ps.getWarnings();
+		while (w != null) {
+			log.log(Level.WARNING, "SQL: {0}", w.getLocalizedMessage());
+			w = w.getNextWarning();
+		}
+		ps.clearWarnings();
+	}
+
+	/**
+	 * Tests if this connection is live.
+	 *
+	 * @return true if test was successful
+	 * @throws SQLException if test fails
+	 */
+	public boolean test() throws SQLException {
+		connection.getAutoCommit();
+		return true;
+	}
+
+	public String getProductName() throws SQLException {
+		return connection.getMetaData().getDatabaseProductName();
+	}
+
+	public String getProductVersion() throws SQLException {
+		return connection.getMetaData().getDatabaseProductVersion();
+	}
+
+	@Override
+	public void close() throws SQLException {
+		connection.close();
+	}
+}