Airline example corrected

Doc/Sda1/prerequisites.xml

@@ -20,7 +20,7 @@
       </listitem>
 
       <listitem>
-        <para>Upload to  <uri
+        <para>Upload to <uri
         xlink:href="https://learn.mi.hdm-stuttgart.de/files/CheatSheet">https://learn.mi.hdm-stuttgart.de/files/CheatSheet</uri>.</para>
       </listitem>
 
@@ -31,14 +31,13 @@
       <listitem>
         <para>Subsequent transfer to read-only location <uri
         xlink:href="https://klausur.mi.hdm-stuttgart.de/files/goik/CheatSheet">https://klausur.mi.hdm-stuttgart.de/files/goik/CheatSheet</uri>
-	accessible during exam time.</para>
+        accessible during exam time.</para>
       </listitem>
 
       <listitem>
         <para><emphasis role="red">Check your transferred archive prior to
         examination!</emphasis></para>
       </listitem>
-      
     </itemizedlist>
   </figure>
 
@@ -263,8 +262,8 @@ PGPASSWORD=XYZ psql -h localhost --username=hdmuser -d hdm <co
       server:</para>
 
       <figure xml:id="sda1_fig_mysqlDriverByAptitude">
-        <title>Installing <xref linkend="glo_Soft_Postgresql"/> JDBC driver using the
-        <command
+        <title>Installing <xref linkend="glo_Soft_Postgresql"/> JDBC driver
+        using the <command
         xlink:href="https://linux.die.net/man/8/aptitude">aptitude</command>.</title>
 
         <screen>#&gt; apt-get install libpostgresql-jdbc-java</screen>
@@ -376,7 +375,8 @@ PGPASSWORD=XYZ psql -h localhost --username=hdmuser -d hdm <co
                   </listitem>
 
                   <listitem>
-                    <para>Constraint: origin and destination must differ.</para>
+                    <para>Constraint: origin and destination must
+                    differ.</para>
                   </listitem>
                 </itemizedlist>
               </listitem>
@@ -396,38 +396,40 @@ DROP  TABLE IF EXISTS Destination;
 DROP  TABLE IF EXISTS Airline;
 
 CREATE Table Airline (
-   id INT NOT NULL
-  ,name CHAR(20) NOT NULL
-  ,airlineCode CHAR(5) NOT NULL
+    id INT NOT NULL
+    ,name CHAR(20) NOT NULL
+    ,airlineCode CHAR(5) NOT NULL
 
-  ,CONSTRAINT _PK_Airline_id PRIMARY KEY(id)
-  ,CONSTRAINT _UN_Airline_name UNIQUE(name)
-  ,CONSTRAINT _UN_Airline_airlineCode UNIQUE(airlineCode)
+    ,CONSTRAINT _PK_Airline_id PRIMARY KEY(id)
+    ,CONSTRAINT _UN_Airline_name UNIQUE(name)
+    ,CONSTRAINT _UN_Airline_airlineCode UNIQUE(airlineCode)
 );
 
 CREATE TABLE Destination (
-   id INT NOT NULL
-  ,fullName CHAR(20) NOT NULL
-  ,airportCode CHAR(5)
+    id INT NOT NULL
+    ,fullName CHAR(20) NOT NULL
+    ,airportCode CHAR(5)
 
-  ,CONSTRAINT _PK_Destination_id PRIMARY KEY(id)
-  ,CONSTRAINT _UN_Destination_airportCode UNIQUE(airportCode)
+    ,CONSTRAINT _PK_Destination_id PRIMARY KEY(id)
+    ,CONSTRAINT _UN_Destination_airportCode UNIQUE(airportCode)
 );
 
 CREATE TABLE Flight (
-   id INT NOT NULL
-  ,flightNumber CHAR(10) NOT NULL
-  ,airline INT NOT NULL
-  ,origin int NOT NULL
-  ,destination int NOT NULL
+    id INT NOT NULL
+    ,flightNumber CHAR(10) NOT NULL
+    ,airline INT NOT NULL
+    ,origin int NOT NULL
+    ,destination int NOT NULL
 
-  ,CONSTRAINT _PK_Flight_id UNIQUE(id)
-  ,CONSTRAINT _UN_Flight_flightNumber UNIQUE(flightNumber)
+    ,CONSTRAINT _PK_Flight_id UNIQUE(id)
+    ,CONSTRAINT _UN_Flight_flightNumber UNIQUE(flightNumber)
 
-  ,CONSTRAINT _PK_Flight_ref_origin FOREIGN KEY (origin) REFERENCES Destination(id)
-  ,CONSTRAINT _PK_Flight_ref_destination FOREIGN KEY (destination) REFERENCES Destination(id)
+    ,CONSTRAINT _PK_Flight_ref_airline FOREIGN KEY (origin) REFERENCES Airline(id)
 
-  ,CONSTRAINT _CK_Flight_origin_destination CHECK(NOT(origin = destination))
+    ,CONSTRAINT _PK_Flight_ref_origin FOREIGN KEY (origin) REFERENCES Destination(id)
+    ,CONSTRAINT _PK_Flight_ref_destination FOREIGN KEY (destination) REFERENCES Destination(id)
+
+    ,CONSTRAINT _CK_Flight_origin_destination CHECK(NOT(origin = destination))
 );</programlisting>
 
             <para>Compact version using auto generated constraint