diff --git a/src/components/EditorCanvas/Canvas.jsx b/src/components/EditorCanvas/Canvas.jsx
index 44ea706..50daf0d 100644
--- a/src/components/EditorCanvas/Canvas.jsx
+++ b/src/components/EditorCanvas/Canvas.jsx
@@ -400,7 +400,11 @@ export default function Canvas() {
     });
   };
 
-  const handleGripField = () => {
+  const handleGripField = (field) => {
+      if (!field.primary && !(field.notNull && field.unique)) {
+        Toast.info(t("cannot_fk"));
+        return;
+      }
     setPanning((old) => ({ ...old, isPanning: false }));
     setDragging({ element: ObjectType.NONE, id: -1, prevX: 0, prevY: 0 });
     setLinking(true);
diff --git a/src/components/EditorCanvas/Table.jsx b/src/components/EditorCanvas/Table.jsx
index 1e656f9..19f235f 100644
--- a/src/components/EditorCanvas/Table.jsx
+++ b/src/components/EditorCanvas/Table.jsx
@@ -317,10 +317,10 @@ export default function Table(props) {
             onPointerDown={(e) => {
               if (!e.isPrimary) return;
 
-              handleGripField(index);
+              handleGripField(fieldData);
               setLinkingLine((prev) => ({
                 ...prev,
-                startFieldId: index,
+                startFieldId: fieldData.id,
                 startTableId: tableData.id,
                 startX: tableData.x + 15,
                 startY:
diff --git a/src/i18n/locales/en.js b/src/i18n/locales/en.js
index 81c903a..0dad5a4 100644
--- a/src/i18n/locales/en.js
+++ b/src/i18n/locales/en.js
@@ -146,6 +146,7 @@ const en = {
     relationship_deleted: "Relationship deleted",
     type_deleted: "Type deleted",
     cannot_connect: "Cannot connect, the columns have different types",
+    cannot_fk: "Cannot create foreign key from this field",
     copied_to_clipboard: "Copied to clipboard",
     create_new_diagram: "Create new diagram",
     cancel: "Cancel",