diff --git a/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQL.java b/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQL.java
index f28770b..985e74e 100644
--- a/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQL.java
+++ b/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQL.java
@@ -4,11 +4,11 @@
 package org.gcube.accounting.analytics.persistence.postgresql;
 
 import java.sql.Connection;
+import java.sql.DriverManager;
 import java.sql.ResultSet;
 import java.sql.Statement;
 import java.time.OffsetDateTime;
 import java.util.Calendar;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.SortedMap;
@@ -44,11 +44,16 @@ public class AccountingPersistenceQueryPostgreSQL implements AccountingPersisten
 	public static final String DATETIME_PATTERN = "yyyy-MM-dd HH:mm:ss.SSS Z";
 	
 	public static final String URL_PROPERTY_KEY = AccountingPersistenceConfiguration.URL_PROPERTY_KEY;
+	public static final String USERNAME_PROPERTY_KEY = AccountingPersistenceConfiguration.USERNAME_PROPERTY_KEY;
 	public static final String PASSWORD_PROPERTY_KEY = AccountingPersistenceConfiguration.PASSWORD_PROPERTY_KEY;
+
+	private String url;
+	private String username;
+	private String password;
 	
 	protected AccountingPersistenceBackendQueryConfiguration configuration;
 	
-	protected Map<String,String> connectionMap;
+	protected Map<String, String> typeNameToConnectionURL;
 	
 	static {
 		// One Record per package is enough
@@ -65,16 +70,24 @@ public class AccountingPersistenceQueryPostgreSQL implements AccountingPersisten
 		}
 	}
 	
+	protected Connection getConnection(Class<? extends AggregatedRecord<?, ?>> clz) throws Exception {
+		// String typeName = UsageRecordToDBMapping.getRecordToDB(clz).getTypeName();
+		Class.forName("org.postgresql.Driver");
+		Connection connection = DriverManager.getConnection(url, username, password);
+		logger.trace("Database opened successfully");
+		connection.setAutoCommit(false);
+		return connection;
+	}
+	
 	@Override
 	public void prepareConnection(AccountingPersistenceBackendQueryConfiguration configuration) throws Exception {
 		logger.trace("prepareConnection");
-		// String url = configuration.getProperty(URL_PROPERTY_KEY);
 		this.configuration = configuration;
-		this.connectionMap = new HashMap<>();
+		this.url = configuration.getProperty(URL_PROPERTY_KEY);
+		this.username = configuration.getProperty(USERNAME_PROPERTY_KEY);
+		this.password = configuration.getProperty(PASSWORD_PROPERTY_KEY);
 	}
 	
-	
-	
 	@Override
 	public SortedMap<Calendar, Info> getTimeSeries(Class<? extends AggregatedRecord<?, ?>> clz,
 			TemporalConstraint temporalConstraint, List<Filter> filters)
@@ -83,10 +96,6 @@ public class AccountingPersistenceQueryPostgreSQL implements AccountingPersisten
 		return null;
 	}
 	
-	
-	
-	
-	
 	protected Calendar getCalendar(OffsetDateTime offsetDateTime) {
 		Calendar calendar = Calendar.getInstance();
 		long epochMillis = offsetDateTime.toInstant().toEpochMilli();
@@ -98,7 +107,7 @@ public class AccountingPersistenceQueryPostgreSQL implements AccountingPersisten
 	public SortedMap<Calendar, Info> getNoContextTimeSeries(Class<? extends AggregatedRecord<?, ?>> clz,
 			TemporalConstraint temporalConstraint, List<Filter> filters)
 			throws DuplicatedKeyFilterException, KeyException, ValueException, Exception {
-		Connection connection = null;
+		Connection connection = getConnection(clz);
 		Statement statement = connection.createStatement();
 		
 		SortedMap<Calendar, Info> result = new TreeMap<>();
@@ -109,20 +118,27 @@ public class AccountingPersistenceQueryPostgreSQL implements AccountingPersisten
 		String sql = query.getNoContextTimeSeriesQuery();
 		
 		List<String> requestedTableField = query.getRequestedTableField();
+		RecordToDBMapper recordToDBMapper = query.getRecordToDBMapper();
+		
 		ResultSet resultSet = statement.executeQuery(sql);
 		
 		while (resultSet.next()) {
-			
 			OffsetDateTime offsetDateTime = resultSet.getObject(Query.DATE_OF_TIMESERIES_AS_FIELD, OffsetDateTime.class);
 			Calendar calendar = getCalendar(offsetDateTime);
 			
+			JSONObject jsonObject = new JSONObject();
 			
+			for(String tableField : requestedTableField) {
+				String usageRecordField = recordToDBMapper.getUsageRecordField(tableField);
+				Object object = resultSet.getObject(tableField);
+				jsonObject.put(usageRecordField, object);
+			}
 			
+			Info info = new Info(calendar, jsonObject);
+			result.put(calendar, info);
 		}
 		
-		
-		
-		return null;
+		return result;
 	}
 
 	@Override