diff --git a/JDBC_Example/.idea/workspace.xml b/JDBC_Example/.idea/workspace.xml
index 4c54b54..7e21f6f 100644
--- a/JDBC_Example/.idea/workspace.xml
+++ b/JDBC_Example/.idea/workspace.xml
@@ -15,9 +15,11 @@
       <file leaf-file-name="Main.java" pinned="false" current-in-tab="true">
         <entry file="file://$PROJECT_DIR$/src/com/papei/database/Main.java">
           <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="150">
-              <caret line="6" column="10" lean-forward="false" selection-start-line="6" selection-start-column="10" selection-end-line="6" selection-end-column="10" />
-              <folding />
+            <state relative-caret-position="1600">
+              <caret line="64" column="9" lean-forward="true" selection-start-line="64" selection-start-column="9" selection-end-line="64" selection-end-column="9" />
+              <folding>
+                <element signature="imports" expanded="true" />
+              </folding>
             </state>
           </provider>
         </entry>
@@ -64,6 +66,7 @@
       <foldersAlwaysOnTop value="true" />
     </navigator>
     <panes>
+      <pane id="Scope" />
       <pane id="ProjectPane">
         <subPane>
           <expand>
@@ -76,18 +79,26 @@
               <item name="JDBC_Example" type="462c0819:PsiDirectoryNode" />
               <item name="src" type="462c0819:PsiDirectoryNode" />
             </path>
+            <path>
+              <item name="JDBC_Example" type="b2602c69:ProjectViewProjectNode" />
+              <item name="JDBC_Example" type="462c0819:PsiDirectoryNode" />
+              <item name="src" type="462c0819:PsiDirectoryNode" />
+              <item name="database" type="462c0819:PsiDirectoryNode" />
+            </path>
           </expand>
           <select />
         </subPane>
       </pane>
-      <pane id="Scope" />
       <pane id="AndroidView" />
       <pane id="Scratches" />
       <pane id="PackagesPane" />
     </panes>
   </component>
   <component name="PropertiesComponent">
-    <property name="last_opened_file_path" value="$PROJECT_DIR$" />
+    <property name="last_opened_file_path" value="$PROJECT_DIR$/lib" />
+    <property name="project.structure.last.edited" value="Modules" />
+    <property name="project.structure.proportion" value="0.0" />
+    <property name="project.structure.side.proportion" value="0.0" />
   </component>
   <component name="RunDashboard">
     <option name="ruleStates">
@@ -109,6 +120,25 @@
       <option name="POLICY_FILE" value="$APPLICATION_HOME_DIR$/bin/appletviewer.policy" />
       <module />
     </configuration>
+    <configuration name="Main" type="Application" factoryName="Application" temporary="true" nameIsGenerated="true">
+      <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea">
+        <pattern>
+          <option name="PATTERN" value="com.papei.database.*" />
+          <option name="ENABLED" value="true" />
+        </pattern>
+      </extension>
+      <option name="MAIN_CLASS_NAME" value="com.papei.database.Main" />
+      <option name="VM_PARAMETERS" />
+      <option name="PROGRAM_PARAMETERS" />
+      <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$" />
+      <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
+      <option name="ALTERNATIVE_JRE_PATH" />
+      <option name="ENABLE_SWING_INSPECTOR" value="false" />
+      <option name="ENV_VARIABLES" />
+      <option name="PASS_PARENT_ENVS" value="true" />
+      <module name="JDBC_Example" />
+      <envs />
+    </configuration>
     <configuration default="true" type="Application" factoryName="Application">
       <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
       <option name="MAIN_CLASS_NAME" />
@@ -183,6 +213,11 @@
       <option name="PROGRAM_PARAMETERS" />
       <predefined_log_file id="idea.log" enabled="true" />
     </configuration>
+    <recent_temporary>
+      <list size="1">
+        <item index="0" class="java.lang.String" itemvalue="Application.Main" />
+      </list>
+    </recent_temporary>
   </component>
   <component name="ShelveChangesManager" show_recycled="false">
     <option name="remove_strategy" value="false" />
@@ -206,12 +241,13 @@
     <layout>
       <window_info id="Palette" active="false" anchor="right" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.33" sideWeight="0.5" order="3" side_tool="false" content_ui="tabs" />
       <window_info id="TODO" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.33" sideWeight="0.5" order="6" side_tool="false" content_ui="tabs" />
+      <window_info id="Messages" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.32934782" sideWeight="0.5" order="-1" side_tool="false" content_ui="tabs" />
       <window_info id="Palette&#9;" active="false" anchor="right" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.33" sideWeight="0.5" order="3" side_tool="false" content_ui="tabs" />
       <window_info id="Image Layers" active="false" anchor="left" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.33" sideWeight="0.5" order="2" side_tool="false" content_ui="tabs" />
       <window_info id="Capture Analysis" active="false" anchor="right" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.33" sideWeight="0.5" order="3" side_tool="false" content_ui="tabs" />
       <window_info id="Event Log" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.33" sideWeight="0.5" order="7" side_tool="true" content_ui="tabs" />
       <window_info id="Maven Projects" active="false" anchor="right" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.33" sideWeight="0.5" order="3" side_tool="false" content_ui="tabs" />
-      <window_info id="Run" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.33" sideWeight="0.5" order="2" side_tool="false" content_ui="tabs" />
+      <window_info id="Run" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.36086956" sideWeight="0.5" order="2" side_tool="false" content_ui="tabs" />
       <window_info id="Version Control" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="false" weight="0.33" sideWeight="0.5" order="7" side_tool="false" content_ui="tabs" />
       <window_info id="Terminal" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.33" sideWeight="0.5" order="7" side_tool="false" content_ui="tabs" />
       <window_info id="Capture Tool" active="false" anchor="left" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.33" sideWeight="0.5" order="2" side_tool="false" content_ui="tabs" />
@@ -243,21 +279,94 @@
       <provider selected="true" editor-type-id="text-editor">
         <state relative-caret-position="0">
           <caret line="0" column="0" lean-forward="false" selection-start-line="0" selection-start-column="0" selection-end-line="0" selection-end-column="0" />
-          <folding />
+          <folding>
+            <element signature="imports" expanded="true" />
+          </folding>
         </state>
       </provider>
     </entry>
     <entry file="file://$PROJECT_DIR$/src/com/papei/database/Main.java">
       <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="150">
-          <caret line="6" column="10" lean-forward="false" selection-start-line="6" selection-start-column="10" selection-end-line="6" selection-end-column="10" />
-          <folding />
+        <state relative-caret-position="0">
+          <caret line="0" column="0" lean-forward="false" selection-start-line="0" selection-start-column="0" selection-end-line="0" selection-end-column="0" />
+          <folding>
+            <element signature="imports" expanded="true" />
+          </folding>
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/src/com/papei/database/Main.java">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="1600">
+          <caret line="64" column="9" lean-forward="true" selection-start-line="64" selection-start-column="9" selection-end-line="64" selection-end-column="9" />
+          <folding>
+            <element signature="imports" expanded="true" />
+          </folding>
         </state>
       </provider>
     </entry>
   </component>
   <component name="masterDetails">
     <states>
+      <state key="ArtifactsStructureConfigurable.UI">
+        <settings>
+          <artifact-editor />
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="FacetStructureConfigurable.UI">
+        <settings>
+          <last-edited>No facets are configured</last-edited>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="GlobalLibrariesConfigurable.UI">
+        <settings>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="JdkListConfigurable.UI">
+        <settings>
+          <last-edited>1.8</last-edited>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="ModuleStructureConfigurable.UI">
+        <settings>
+          <last-edited>JDBC_Example</last-edited>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
       <state key="ProjectJDKs.UI">
         <settings>
           <last-edited>1.8</last-edited>
@@ -270,6 +379,17 @@
           </splitter-proportions>
         </settings>
       </state>
+      <state key="ProjectLibrariesConfigurable.UI">
+        <settings>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
     </states>
   </component>
 </project>
\ No newline at end of file
diff --git a/JDBC_Example/JDBC_Example.iml b/JDBC_Example/JDBC_Example.iml
index c90834f..86d67bf 100644
--- a/JDBC_Example/JDBC_Example.iml
+++ b/JDBC_Example/JDBC_Example.iml
@@ -7,5 +7,15 @@
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="module-library">
+      <library>
+        <CLASSES>
+          <root url="file://$MODULE_DIR$/lib" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+        <jarDirectory url="file://$MODULE_DIR$/lib" recursive="false" />
+      </library>
+    </orderEntry>
   </component>
 </module>
\ No newline at end of file
diff --git a/JDBC_Example/lib/postgresql-42.2.2.jar b/JDBC_Example/lib/postgresql-42.2.2.jar
new file mode 100644
index 0000000..530af83
Binary files /dev/null and b/JDBC_Example/lib/postgresql-42.2.2.jar differ
diff --git a/JDBC_Example/out/production/JDBC_Example/com/papei/database/Main.class b/JDBC_Example/out/production/JDBC_Example/com/papei/database/Main.class
new file mode 100644
index 0000000..d19e3cd
Binary files /dev/null and b/JDBC_Example/out/production/JDBC_Example/com/papei/database/Main.class differ
diff --git a/JDBC_Example/src/com/papei/database/Main.java b/JDBC_Example/src/com/papei/database/Main.java
index 603488c..323e0be 100644
--- a/JDBC_Example/src/com/papei/database/Main.java
+++ b/JDBC_Example/src/com/papei/database/Main.java
@@ -1,8 +1,142 @@
 package com.papei.database;
 
+import java.sql.*;
+import java.util.Properties;
+
 public class Main
 {
-	public static void main(String[] args)
+	private static final String Domain = "localhost";
+	private static final int Port = 5432;
+	private static final String Database_Name = "ergasia";
+	private static final String Username = "thanos";
+	private static final String Password = "paravantis";
+	private static final String URL = "jdbc:postgresql://" + Domain + ":" + Port + "/" + Database_Name;
+	private static Connection conn;
+
+	public static void main(String[] args) throws ClassNotFoundException
+	{
+		Class.forName("org.postgresql.Driver");
+
+		try
+		{
+			conn = DriverManager.getConnection(URL, Username, Password);
+		}
+		catch (SQLException e)
+		{
+			System.out.println("Could not connect to PostgreSQL!");
+			e.printStackTrace();
+		}
+
+		execute2a();
+
+		System.out.println();
+
+		execute2b();
+
+		System.out.println();
+
+		execute2c();
+	}
+
+	private static void execute2a()
+	{
+		System.out.println("Erotima A");
+
+		Statement statement = null;
+		String query = "SELECT * FROM COUNT_MODELS WHERE COUNT_MODELS.num_of_model = (SELECT max(num_of_model) AS maximum FROM COUNT_MODELS);";
+		try
+		{
+			statement = conn.createStatement();
+			ResultSet res = statement.executeQuery(query);
+
+			System.out.println("ID\tTitle\tNumber of Models");
+
+			while (res.next())
+			{
+				String id = res.getString("id");
+				String title = res.getString("title");
+				String numberOfModels = res.getString("num_of_model");
+				System.out.println(id + "\t" + title + "\t" + numberOfModels);
+			}
+		}
+		catch (SQLException e)
+		{
+			e.printStackTrace();
+		}
+	}
+
+	private static void execute2b()
+	{
+		System.out.println("Erotima B");
+
+		Statement statement = null;
+		String query = "SELECT to_char(start_date, 'Month') as month, ROUND(AVG(cost)::numeric, 2) as avg_profit "
+				+ "FROM service_history "
+				+ "GROUP BY to_char(start_date, 'Month') "
+				+ "ORDER BY avg_profit DESC";
+
+		try
+		{
+			statement = conn.createStatement();
+			ResultSet res = statement.executeQuery(query);
+
+			System.out.println("Month\tAverage Profit");
+
+			while (res.next())
+			{
+				String month = res.getString("month");
+				String avgProfit = res.getString("avg_profit");
+				System.out.println(month + "\t" + avgProfit);
+			}
+		}
+		catch (SQLException e)
+		{
+			e.printStackTrace();
+		}
+	}
+
+	private static void execute2c()
+	{
+		System.out.println("Erotima C");
+
+		Statement statement = null;
+		String query = "SELECT salesman_id, employee.first_name, employee.last_name, profit "
+				+ "FROM PROFIT INNER JOIN employee ON PROFIT.salesman_id = employee.id "
+				+ "WHERE profit = (SELECT max(profit) FROM PROFIT);";
+
+		try
+		{
+			statement = conn.createStatement();
+			ResultSet res = statement.executeQuery(query);
+
+			System.out.println("ID\tFirst Name\tLastName\tProfit\t");
+
+			while (res.next())
+			{
+				String id = res.getString("salesman_id");
+				String firstName = res.getString("first_name");
+				String lastName = res.getString("last_name");
+				int profit = res.getInt("profit");
+				System.out.println(id + "\t" + firstName+ "\t" + lastName + "\t" + profit);
+			}
+		}
+		catch (SQLException e)
+		{
+			e.printStackTrace();
+		}
+	}
+
+	private static void execute2d()
+	{
+		//
+	}
+
+	private static void execute2e()
+	{
+		//
+	}
+
+	private static void execute2f()
 	{
 		//
 	}