diff --git a/example.png b/example.png
index 770c24c..0374bf5 100644
Binary files a/example.png and b/example.png differ
diff --git a/src/Command/DoctrinevizCommand.php b/src/Command/DoctrinevizCommand.php
index 91cad2e..c13466f 100644
--- a/src/Command/DoctrinevizCommand.php
+++ b/src/Command/DoctrinevizCommand.php
@@ -96,15 +96,19 @@ public function execute(InputInterface $input, OutputInterface $output)
                         foreach ($joinColumns as $joinColumn) {
                             $record = new Record($this->getFieldMappingDisplayName($joinColumn, 'name'));
                             $table->addRecord($record);
+                            $nullable = false;
                             if (array_key_exists($sourceEntity, $tables)) {
                                 $name = $this->getFieldMappingDisplayName($joinColumn, 'referencedColumnName');
+                                $nullable = $joinColumn['nullable'];
                                 $to = $graph->getVertex($tables[$sourceEntity]->getId())->getRecord($name);
                                 if (!$to) {
                                     $to = new Record($name);
                                     $tables[$sourceEntity]->addRecord($to);
                                 }
                             }
-                            $record->addEdgeTo($to, '* 1');
+                            $edge = $record->addEdgeTo($to);
+                            $edge->createAttribute('headlabel', $nullable ? '0..1' : '1');
+                            $edge->createAttribute('taillabel', '*');
                         }
                     }
                     if (array_key_exists('inverseJoinColumns', $joinTable)) {
@@ -113,15 +117,19 @@ public function execute(InputInterface $input, OutputInterface $output)
                         foreach ($inverseJoinColumns as $inverseJoinColumn) {
                             $record = new Record($this->getFieldMappingDisplayName($inverseJoinColumn, 'name'));
                             $table->addRecord($record);
+                            $nullable = false;
                             if (array_key_exists($targetEntity, $tables)) {
                                 $name = $this->getFieldMappingDisplayName($inverseJoinColumn, 'referencedColumnName');
+                                $nullable = $inverseJoinColumn['nullable'];
                                 $to = $graph->getVertex($tables[$targetEntity]->getId())->getRecord($name);
                                 if (!$to) {
                                     $to = new Record($name);
                                     $tables[$targetEntity]->addRecord($to);
                                 }
                             }
-                            $record->addEdgeTo($to, '* 1');
+                            $edge = $record->addEdgeTo($to);
+                            $edge->createAttribute('headlabel', $nullable ? '0..1' : '1');
+                            $edge->createAttribute('taillabel', '*');
                         }
                     }
                     $tables[$table->getId()] = $table;
@@ -145,7 +153,13 @@ public function execute(InputInterface $input, OutputInterface $output)
                         ]));
                         $tables[$entity]->addRecord($from);
                     }
-                    $from->addEdgeTo($to, $this->getCardinality($associationMapping));
+                    $joinColumn = $associationMapping['joinColumns'][0];
+                    $nullable = !array_key_exists('nullable', $joinColumn) || $joinColumn['nullable'];
+                    $edge = $from->addEdgeTo($to);
+                    $edge->createAttribute('headlabel', $nullable ? '0..1' : '1');
+                    if (array_key_exists('type', $associationMapping)) {
+                        $edge->createAttribute('taillabel', ClassMetadataInfo::ONE_TO_ONE === $associationMapping['type'] ? '1' : '*');
+                    }
                 }
             }
         }
@@ -167,24 +181,6 @@ public function execute(InputInterface $input, OutputInterface $output)
         }
     }
 
-    protected function getCardinality(array $fieldMapping)
-    {
-        if (!array_key_exists('type', $fieldMapping)) {
-            return null;
-        }
-
-        switch ($fieldMapping['type']) {
-            case ClassMetadataInfo::ONE_TO_ONE:
-                return '1 1';
-            case ClassMetadataInfo::ONE_TO_MANY:
-                return '1 *';
-            case ClassMetadataInfo::MANY_TO_ONE:
-                return '* 1';
-            case ClassMetadataInfo::MANY_TO_MANY:
-                return '* *';
-        }
-    }
-
     /**
      * Get field mapping display name.
      *
diff --git a/src/Graphviz/Edgeable.php b/src/Graphviz/Edgeable.php
index c62c21f..e246feb 100644
--- a/src/Graphviz/Edgeable.php
+++ b/src/Graphviz/Edgeable.php
@@ -45,13 +45,16 @@ public function setGraph($graph)
      *
      * @param Vertex|Record $element
      * @param null|string   $label
+     *
+     * @return Edge
      */
     public function addEdgeTo($element, $label = null)
     {
         if (!$this->graph) {
             throw new \RuntimeException('Graph is not defined');
         }
-        $this->graph->addEdge(new Edge($this, $element, $label));
+
+        return $this->graph->addEdge(new Edge($this, $element, $label));
     }
 
     /**
@@ -73,13 +76,16 @@ public function removeEdgeTo($element, $label = null)
      *
      * @param Vertex|Record $element
      * @param null|string   $label
+     *
+     * @return Edge
      */
     public function addEdgeFrom($element, $label = null)
     {
         if (!$this->graph) {
             throw new \RuntimeException('Graph is not defined');
         }
-        $this->graph->addEdge(new Edge($element, $this, $label));
+
+        return $this->graph->addEdge(new Edge($element, $this, $label));
     }
 
     /**
diff --git a/src/Graphviz/Graph.php b/src/Graphviz/Graph.php
index 90f8347..3c84cac 100644
--- a/src/Graphviz/Graph.php
+++ b/src/Graphviz/Graph.php
@@ -152,10 +152,14 @@ public function getEdge($id)
      * Add edge.
      *
      * @param Edge $edge
+     *
+     * @return Edge
      */
     public function addEdge(Edge $edge)
     {
         $this->edges[(string) $edge] = $edge;
+
+        return $edge;
     }
 
     /**
diff --git a/test/Command/DoctrinevizCommandTest.php b/test/Command/DoctrinevizCommandTest.php
index 547216d..e58880c 100644
--- a/test/Command/DoctrinevizCommandTest.php
+++ b/test/Command/DoctrinevizCommandTest.php
@@ -77,16 +77,20 @@ public function testExecuteDotFormatting()
             '    label="USER_GROUP|<group_id> group_id : integer\\l|<user_id> user_id : integer\\l"'.PHP_EOL.
             '  ]'.PHP_EOL.
             '  user:address_id : integer -> address:id : integer ['.PHP_EOL.
-            '    label="* 1"'.PHP_EOL.
+            '    headlabel="0..1"'.PHP_EOL.
+            '    taillabel="*"'.PHP_EOL.
             '  ];'.PHP_EOL.
             '  user:email_id : integer -> email:id : integer ['.PHP_EOL.
-            '    label="1 1"'.PHP_EOL.
+            '    headlabel="1"'.PHP_EOL.
+            '    taillabel="1"'.PHP_EOL.
             '  ];'.PHP_EOL.
             '  user_group:group_id : integer -> group:id : integer ['.PHP_EOL.
-            '    label="* 1"'.PHP_EOL.
+            '    headlabel="0..1"'.PHP_EOL.
+            '    taillabel="*"'.PHP_EOL.
             '  ];'.PHP_EOL.
             '  user_group:user_id : integer -> user:id : integer ['.PHP_EOL.
-            '    label="* 1"'.PHP_EOL.
+            '    headlabel="0..1"'.PHP_EOL.
+            '    taillabel="*"'.PHP_EOL.
             '  ];'.PHP_EOL.
             '}'.PHP_EOL;
         $client = static::createClient();
diff --git a/test/Entity/User.php b/test/Entity/User.php
index 9dd3416..81abaad 100644
--- a/test/Entity/User.php
+++ b/test/Entity/User.php
@@ -47,7 +47,7 @@ class User
 
     /**
      * @ORM\OneToOne(targetEntity="Email")
-     * @ORM\JoinColumn(name="email_id", referencedColumnName="id")
+     * @ORM\JoinColumn(name="email_id", nullable=false, referencedColumnName="id")
      */
     protected $email;