diff --git a/dblayer.php b/dblayer.php
index 6c27471..d08f81a 100644
--- a/dblayer.php
+++ b/dblayer.php
@@ -206,15 +206,60 @@ class dblayer extends PDO
       if (in_array ("not null", $params) && !array_key_exists ($key, $datas))
         throw new Exception (sprintf (_("Mandatory field '%s' not provided"),
                                       $key), 405);
+      if (in_array ("not null", $params) && $datas[$key] === "")
+        throw new Exception (sprintf (_("Mandatory field '%s' is empty"),
+                                      $key), 405);
       if (!array_key_exists ($key, $datas))
         continue;
       // Verify the fields, if $verify is defined, before doing insertion
       $verify = $this->verifyOne ($key, $datas[$key]);
       if (is_array ($verify) && count ($verify))
         throw new Exception ($verify[0]." ".$verify[1]." in ".$key);
-      // TODO : Check for type inconsistencies before create $datasOK
-      if (array_key_exists ($key, $datas))
-        $datasOK[$key] = $datas[$key];
+      // Check for type inconsistencies if the value is provided
+      if ($datas[$key] !== "" && $params[0] === "integer")
+      {
+        if (strspn ($datas[$key], "0123456789") !== strlen ($datas[$key]))
+          throw new Exception (sprintf (
+                            _("Errors in consistency : '%s' is not an integer"),
+                            $key), 405);
+      }
+      elseif ($datas[$key] !== "" && $params[0] === "varchar")
+      {
+        if (! isset ($params[1]))
+          throw new Exception (sprintf (
+                          _("The length of varchar field '%s' is not provided"),
+                          $key), 500);
+        if (strlen ($datas[$key]) > $params[1])
+          throw new Exception (sprintf (
+                             _("Errors in consistency : '%s' data is too long"),
+                             $key), 405);
+      }
+      elseif ($datas[$key] !== "" && $params[0] === "datetime")
+      {
+        // The date format must be in ANSI SQL : YYYY-MM-DD HH:MM:SS
+        $d = DateTime::createFromFormat("Y-m-d H:i:s", $datas[$key]);
+        if (!$d || $d->format("Y-m-d H:i:s") !== $datas[$key])
+          throw new Exception (sprintf (
+                                _("Incorrect datetime provided for field '%s'"),
+                                $key), 500);
+      }
+      elseif ($datas[$key] !== "" && $params[0] === "date")
+      {
+        // The date format must be in ANSI SQL : YYYY-MM-DD
+        $d = DateTime::createFromFormat("Y-m-d", $datas[$key]);
+        if (!$d || $d->format("Y-m-d") !== $datas[$key])
+          throw new Exception (sprintf (
+                                    _("Incorrect date provided for field '%s'"),
+                                    $key), 500);
+      }
+      elseif ($datas[$key] !== "")
+        throw new Exception (sprintf (_("Unknown field type for '%s'"), $key),
+                             500);
+      else
+      {
+        // Nothing to do if the value is empty : just save it
+      }
+      $datasOK[$key] = $datas[$key];
     }
 
     // Check for inconsistency