diff --git a/skel/pages/add().php b/skel/pages/add().php
index f810ab1..74ca427 100644
--- a/skel/pages/add().php
+++ b/skel/pages/add().php
@@ -1,12 +1,18 @@
 <?php echo '<?php' ?>
-<?php foreach ($belongsTo as $relation): ?>
-$<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?> = DB::selectPairs('select `<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_COLUMN_NAME']; ?>`,`<?php echo $findDisplayField($relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']); ?>` from `<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?>`');
+<?php foreach ($belongsTo as $relation): $referencedTable = $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; $referencedColumn = $relation['KEY_COLUMN_USAGE']['REFERENCED_COLUMN_NAME']; ?>
+$<?php echo $referencedTable; ?> = DB::selectPairs('select `<?php echo $referencedColumn; ?>`,`<?php echo $findDisplayField($referencedTable); ?>` from `<?php echo $referencedTable; ?>`');
 <?php endforeach;?>
 if ($_SERVER['REQUEST_METHOD']=='POST') {
     $data = $_POST;
-<?php foreach ($belongsTo as $relation): ?>
-    if (!isset($<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?>[$data['<?php echo $table; ?>']['<?php echo $relation['KEY_COLUMN_USAGE']['COLUMN_NAME']; ?>']])) $errors['<?php echo $table; ?>[<?php echo $relation['KEY_COLUMN_USAGE']['COLUMN_NAME']; ?>]']='<?php echo ucfirst($singularize($humanize($relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']))); ?> not found';
+<?php foreach ($belongsTo as $relation): $referencedTable = $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; $column = $relation['KEY_COLUMN_USAGE']['COLUMN_NAME']; ?>
+    if (!isset($<?php echo $referencedTable; ?>[$data['<?php echo $table; ?>']['<?php echo $column; ?>']])) $errors['<?php echo $table; ?>[<?php echo $column; ?>]']='<?php echo ucfirst($singularize($humanize($referencedTable))); ?> not found';
 <?php endforeach;?>
+<?php foreach ($fields as $field): if (!$field['COLUMNS']['IS_NULLABLE']): $column = $field['COLUMNS']['COLUMN_NAME']; ?>
+    if (!$data['<?php echo $table; ?>']['<?php echo $column; ?>']) $errors['<?php echo $table; ?>[<?php echo $column; ?>]']='<?php echo ucfirst($humanize($column)); ?> must be filled';
+<?php endif; endforeach;?>
+<?php foreach ($fields as $field): if ($field['COLUMNS']['IS_NULLABLE']): $column = $field['COLUMNS']['COLUMN_NAME']; ?>
+    if (!$data['<?php echo $table; ?>']['<?php echo $column; ?>']) $data['<?php echo $table; ?>']['<?php echo $column; ?>']=null;
+<?php endif; endforeach;?>
     if (!isset($errors)) {
         $id = DB::insert('INSERT INTO `<?php echo $table; ?>` (<?php echo implode(', ', array_map(function ($field) {return '`' . $field['COLUMNS']['COLUMN_NAME'] . '`';}, $fields)); ?>) VALUES (<?php echo implode(', ', array_map(function () {return '?';}, $fields)); ?>)', <?php echo implode(', ', array_map(function ($field) use ($table) {return "\$data['$table']['" . $field['COLUMNS']['COLUMN_NAME'] . "']";}, $fields)); ?>);
         if ($id) {
diff --git a/skel/pages/add(admin).phtml b/skel/pages/add(admin).phtml
index 258f81b..293ade5 100644
--- a/skel/pages/add(admin).phtml
+++ b/skel/pages/add(admin).phtml
@@ -2,21 +2,21 @@
   <h1>New <?php echo $singularize($humanize($table)); ?></h1>
 </div>
 <form method="post">
-<?php foreach ($fields as $field): ?>
-    <div class="form-group <?php echo '<?php' ?> e(isset($errors['<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]'])?'has-error':''); ?>">
-<?php if ($relation = $findBelongsTo($field['COLUMNS']['COLUMN_NAME'])): ?>
-        <label class="control-label" for="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]"><?php echo ucfirst($singularize($humanize($relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']))); ?></label>
-        <select class="form-control" name="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]" id="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]">
-            <option value=""<?php echo '<?php' ?> e(''==$data['<?php echo $table; ?>']['<?php echo $field['COLUMNS']['COLUMN_NAME'] ?>']?' selected="selected"':''); ?>>...</option>
-            <?php echo '<?php' ?> foreach ($<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?> as $key => $value): ?>
-            <option value="<?php echo '<?php' ?> e($key); ?>"<?php echo '<?php' ?> e($key==$data['<?php echo $table; ?>']['<?php echo $field['COLUMNS']['COLUMN_NAME'] ?>']?' selected="selected"':''); ?>><?php echo '<?php' ?> e($value); ?></option>
-            <?php echo '<?php' ?> endforeach; ?>
-        </select>
+<?php foreach ($fields as $field): $column = $field['COLUMNS']['COLUMN_NAME']; $optional = $field['COLUMNS']['IS_NULLABLE'];?>
+	<div class="form-group <?php echo $optional?'optional ':''; ?><?php echo '<?php' ?> e(isset($errors['<?php echo $table; ?>[<?php echo $column; ?>]'])?'has-error':''); ?>">
+<?php if ($relation = $findBelongsTo($column)): $referencedTable = $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME'];?>
+	    <label class="control-label" for="<?php echo $table; ?>[<?php echo $column; ?>]"><?php echo ucfirst($singularize($humanize($referencedTable))); ?></label>
+	    <select class="form-control" name="<?php echo $table; ?>[<?php echo $column; ?>]" id="<?php echo $table; ?>[<?php echo $column; ?>]"<?php echo $optional?'':' required'; ?>>
+	        <option value=""<?php echo '<?php' ?> e(''==$data['<?php echo $table; ?>']['<?php echo $column ?>']?' selected="selected"':''); ?>>...</option>
+	        <?php echo '<?php' ?> foreach ($<?php echo $referencedTable; ?> as $key => $value): ?>
+	        <option value="<?php echo '<?php' ?> e($key); ?>"<?php echo '<?php' ?> e($key==$data['<?php echo $table; ?>']['<?php echo $column ?>']?' selected="selected"':''); ?>><?php echo '<?php' ?> e($value); ?></option>
+	        <?php echo '<?php' ?> endforeach; ?>
+	    </select>
 <?php else: ?>
-        <label class="control-label" for="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]"><?php echo ucfirst($humanize($field['COLUMNS']['COLUMN_NAME'])); ?></label>
-        <input class="form-control" name="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]" type="text" value="<?php echo '<?php' ?> e($data['<?php echo $table; ?>']['<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>']); ?>" id="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]" />
+        <label class="control-label" for="<?php echo $table; ?>[<?php echo $column; ?>]"><?php echo ucfirst($humanize($column)); ?></label>
+        <input class="form-control" name="<?php echo $table; ?>[<?php echo $column; ?>]" type="text" value="<?php echo '<?php' ?> e($data['<?php echo $table; ?>']['<?php echo $column; ?>']); ?>" id="<?php echo $table; ?>[<?php echo $column; ?>]" />
 <?php endif;?>
-        <span class="help-block"><?php echo '<?php' ?> e(isset($errors['<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]'])?$errors['<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]']:''); ?></span>
+        <span class="help-block"><?php echo '<?php' ?> e(isset($errors['<?php echo $table; ?>[<?php echo $column; ?>]'])?$errors['<?php echo $table; ?>[<?php echo $column; ?>]']:''); ?></span>
     </div>
 <?php endforeach;?>
 
diff --git a/skel/pages/edit($id).php b/skel/pages/edit($id).php
index 399eebf..d68991c 100644
--- a/skel/pages/edit($id).php
+++ b/skel/pages/edit($id).php
@@ -1,12 +1,18 @@
 <?php echo '<?php' ?>
-<?php foreach ($belongsTo as $relation): ?>
-$<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?> = DB::selectPairs('select `<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_COLUMN_NAME']; ?>`,`<?php echo $findDisplayField($relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']); ?>` from `<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?>`');
+<?php foreach ($belongsTo as $relation): $referencedTable = $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; $referencedColumn = $relation['KEY_COLUMN_USAGE']['REFERENCED_COLUMN_NAME']; ?>
+$<?php echo $referencedTable; ?> = DB::selectPairs('select `<?php echo $referencedColumn; ?>`,`<?php echo $findDisplayField($referencedTable); ?>` from `<?php echo $referencedTable; ?>`');
 <?php endforeach;?>
 if ($_SERVER['REQUEST_METHOD']=='POST') {
     $data = $_POST;
-<?php foreach ($belongsTo as $relation): ?>
-    if (!isset($<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?>[$data['<?php echo $table; ?>']['<?php echo $relation['KEY_COLUMN_USAGE']['COLUMN_NAME']; ?>']])) $errors['<?php echo $table; ?>[<?php echo $relation['KEY_COLUMN_USAGE']['COLUMN_NAME']; ?>]']='<?php echo ucfirst($singularize($humanize($relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']))); ?> not found';
+<?php foreach ($belongsTo as $relation): $referencedTable = $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; $column = $relation['KEY_COLUMN_USAGE']['COLUMN_NAME']; ?>
+    if (!isset($<?php echo $referencedTable; ?>[$data['<?php echo $table; ?>']['<?php echo $column; ?>']])) $errors['<?php echo $table; ?>[<?php echo $column; ?>]']='<?php echo ucfirst($singularize($humanize($referencedTable))); ?> not found';
 <?php endforeach;?>
+<?php foreach ($fields as $field): if (!$field['COLUMNS']['IS_NULLABLE']): $column = $field['COLUMNS']['COLUMN_NAME']; ?>
+    if (!$data['<?php echo $table; ?>']['<?php echo $column; ?>']) $errors['<?php echo $table; ?>[<?php echo $column; ?>]']='<?php echo ucfirst($humanize($column)); ?> must be filled';
+<?php endif; endforeach;?>
+<?php foreach ($fields as $field): if ($field['COLUMNS']['IS_NULLABLE']): $column = $field['COLUMNS']['COLUMN_NAME']; ?>
+    if (!$data['<?php echo $table; ?>']['<?php echo $column; ?>']) $data['<?php echo $table; ?>']['<?php echo $column; ?>']=null;
+<?php endif; endforeach;?>
     if (!isset($errors)) {
         $rowsAffected = DB::update('UPDATE `<?php echo $table; ?>` SET <?php echo implode(', ', array_map(function ($field) {return '`' . $field['COLUMNS']['COLUMN_NAME'] . '`=?';}, $fields)); ?> WHERE `id`=?', <?php echo implode(', ', array_map(function ($field) use ($table) {return "\$data['$table']['" . $field['COLUMNS']['COLUMN_NAME'] . "']";}, $fields)); ?>, $id);
         if ($rowsAffected!==false) {
diff --git a/skel/pages/edit(admin).phtml b/skel/pages/edit(admin).phtml
index 45f012b..38e666d 100644
--- a/skel/pages/edit(admin).phtml
+++ b/skel/pages/edit(admin).phtml
@@ -2,21 +2,21 @@
   <h1>Edit <?php echo $singularize($humanize($table)); ?></h1>
 </div>
 <form method="post">
-<?php foreach ($fields as $field): ?>
-    <div class="form-group <?php echo '<?php' ?> e(isset($errors['<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]'])?'has-error':''); ?>">
-<?php if ($relation = $findBelongsTo($field['COLUMNS']['COLUMN_NAME'])): ?>
-        <label class="control-label" for="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]"><?php echo ucfirst($singularize($humanize($relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']))); ?></label>
-        <select class="form-control" name="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]" id="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]">
-            <option value=""<?php echo '<?php' ?> e(''==$data['<?php echo $table; ?>']['<?php echo $field['COLUMNS']['COLUMN_NAME'] ?>']?' selected="selected"':''); ?>>...</option>
-            <?php echo '<?php' ?> foreach ($<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?> as $key => $value): ?>
-            <option value="<?php echo '<?php' ?> e($key); ?>"<?php echo '<?php' ?> e($key==$data['<?php echo $table; ?>']['<?php echo $field['COLUMNS']['COLUMN_NAME'] ?>']?' selected="selected"':''); ?>><?php echo '<?php' ?> e($value); ?></option>
-            <?php echo '<?php' ?> endforeach; ?>
-        </select>
+<?php foreach ($fields as $field): $column = $field['COLUMNS']['COLUMN_NAME']; $optional = $field['COLUMNS']['IS_NULLABLE'];?>
+	<div class="form-group <?php echo $optional?'optional ':''; ?><?php echo '<?php' ?> e(isset($errors['<?php echo $table; ?>[<?php echo $column; ?>]'])?'has-error':''); ?>">
+<?php if ($relation = $findBelongsTo($column)): $referencedTable = $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME'];?>
+	    <label class="control-label" for="<?php echo $table; ?>[<?php echo $column; ?>]"><?php echo ucfirst($singularize($humanize($referencedTable))); ?></label>
+	    <select class="form-control" name="<?php echo $table; ?>[<?php echo $column; ?>]" id="<?php echo $table; ?>[<?php echo $column; ?>]"<?php echo $optional?'':' required'; ?>>
+	        <option value=""<?php echo '<?php' ?> e(''==$data['<?php echo $table; ?>']['<?php echo $column ?>']?' selected="selected"':''); ?>>...</option>
+	        <?php echo '<?php' ?> foreach ($<?php echo $referencedTable; ?> as $key => $value): ?>
+	        <option value="<?php echo '<?php' ?> e($key); ?>"<?php echo '<?php' ?> e($key==$data['<?php echo $table; ?>']['<?php echo $column ?>']?' selected="selected"':''); ?>><?php echo '<?php' ?> e($value); ?></option>
+	        <?php echo '<?php' ?> endforeach; ?>
+	    </select>
 <?php else: ?>
-        <label class="control-label" for="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]"><?php echo ucfirst($humanize($field['COLUMNS']['COLUMN_NAME'])); ?></label>
-        <input class="form-control" name="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]" type="text" value="<?php echo '<?php' ?> e($data['<?php echo $table; ?>']['<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>']); ?>" id="<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]" />
+        <label class="control-label" for="<?php echo $table; ?>[<?php echo $column; ?>]"><?php echo ucfirst($humanize($column)); ?></label>
+        <input class="form-control" name="<?php echo $table; ?>[<?php echo $column; ?>]" type="text" value="<?php echo '<?php' ?> e($data['<?php echo $table; ?>']['<?php echo $column; ?>']); ?>" id="<?php echo $table; ?>[<?php echo $column; ?>]" />
 <?php endif;?>
-        <span class="help-block"><?php echo '<?php' ?> e(isset($errors['<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]'])?$errors['<?php echo $table; ?>[<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>]']:''); ?></span>
+        <span class="help-block"><?php echo '<?php' ?> e(isset($errors['<?php echo $table; ?>[<?php echo $column; ?>]'])?$errors['<?php echo $table; ?>[<?php echo $column; ?>]']:''); ?></span>
     </div>
 <?php endforeach;?>
 
diff --git a/skel/pages/index(admin).phtml b/skel/pages/index(admin).phtml
index bd94b69..9d79d83 100644
--- a/skel/pages/index(admin).phtml
+++ b/skel/pages/index(admin).phtml
@@ -2,8 +2,8 @@
 <table class="table">
   <thead>
     <tr>
-<?php foreach ($fields as $field): 
-      if ($relation = $findBelongsTo($field['COLUMNS']['COLUMN_NAME'])): ?>
+<?php foreach ($fields as $field): $column = $field['COLUMNS']['COLUMN_NAME']; 
+      if ($relation = $findBelongsTo($field['COLUMNS']['COLUMN_NAME'])): $referencedTable = $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?>
       <th><?php echo ucfirst($singularize($humanize($relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']))); ?></th>
 <?php else: ?>
       <th><?php echo ucfirst($humanize($field['COLUMNS']['COLUMN_NAME'])); ?></th>
@@ -14,8 +14,8 @@
   <tbody>
     <?php echo '<?php' ?> foreach ($data as $row): ?>
     <tr>
-<?php foreach ($fields as $field):  
-      if ($relation = $findBelongsTo($field['COLUMNS']['COLUMN_NAME'])): ?>
+<?php foreach ($fields as $field): $column = $field['COLUMNS']['COLUMN_NAME'];
+      if ($relation = $findBelongsTo($field['COLUMNS']['COLUMN_NAME'])): $referencedTable = $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?>
       <td><?php echo '<?php' ?> e($<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?>[$row['<?php echo $table; ?>']['<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>']]);?></td>
 <?php else: ?>
       <td><?php echo '<?php' ?> e($row['<?php echo $table; ?>']['<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>']);?></td>
diff --git a/skel/pages/view($id).php b/skel/pages/view($id).php
index 2460598..3f4feb6 100644
--- a/skel/pages/view($id).php
+++ b/skel/pages/view($id).php
@@ -1,5 +1,5 @@
 <?php echo '<?php' ?> 
 $data = DB::selectOne('select * from `<?php echo $table; ?>` where `id`=?',$id);
-<?php foreach ($belongsTo as $relation): ?>
-$<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?> = DB::selectPairs('select `<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_COLUMN_NAME']; ?>`,`<?php echo $findDisplayField($relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']); ?>` from `<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?>`');
+<?php foreach ($belongsTo as $relation): $referencedTable = $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; $referencedColumn = $relation['KEY_COLUMN_USAGE']['REFERENCED_COLUMN_NAME']; ?>
+$<?php echo $referencedTable; ?> = DB::selectPairs('select `<?php echo $referencedColumn; ?>`,`<?php echo $findDisplayField($referencedTable); ?>` from `<?php echo $referencedTable; ?>`');
 <?php endforeach; ?>
\ No newline at end of file
diff --git a/skel/pages/view(admin).phtml b/skel/pages/view(admin).phtml
index 914284e..b634b6c 100644
--- a/skel/pages/view(admin).phtml
+++ b/skel/pages/view(admin).phtml
@@ -2,17 +2,17 @@
   <h1>View <?php echo $singularize($humanize($table)); ?></h1>
 </div>
 <div>
-<?php foreach ($fields as $field): ?>
+<?php foreach ($fields as $field): $column = $field['COLUMNS']['COLUMN_NAME']; ?>
     <dl>
-<?php if ($relation = $findBelongsTo($field['COLUMNS']['COLUMN_NAME'])): ?>
-        <dt><?php echo ucfirst($singularize($humanize($relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']))); ?></dt>
+<?php if ($relation = $findBelongsTo($column)): $referencedTable = $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?>
+        <dt><?php echo ucfirst($singularize($humanize($referencedTable))); ?></dt>
 <?php else: ?>
-        <dt><?php echo ucfirst($humanize($field['COLUMNS']['COLUMN_NAME'])); ?></dt>
+        <dt><?php echo ucfirst($humanize($column)); ?></dt>
 <?php endif;?>
-<?php if ($relation = $findBelongsTo($field['COLUMNS']['COLUMN_NAME'])): ?>
-          <dd><?php echo '<?php' ?> e($<?php echo $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?>[$data['<?php echo $table; ?>']['<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>']]);?></dd>
+<?php if ($relation = $findBelongsTo($column)): $referencedTable = $relation['KEY_COLUMN_USAGE']['REFERENCED_TABLE_NAME']; ?>
+          <dd><?php echo '<?php' ?> e($<?php echo $referencedTable; ?>[$data['<?php echo $table; ?>']['<?php echo $column; ?>']]);?></dd>
 <?php else: ?>
-          <dd><?php echo '<?php' ?> e($data['<?php echo $table; ?>']['<?php echo $field['COLUMNS']['COLUMN_NAME']; ?>']);?></dd>
+          <dd><?php echo '<?php' ?> e($data['<?php echo $table; ?>']['<?php echo $column; ?>']);?></dd>
 <?php endif;?>
       </dl>
 <?php endforeach;?>