diff --git a/backend/open_webui/migrations/versions/38d63c18f30f_add_oauth_session_table.py b/backend/open_webui/migrations/versions/38d63c18f30f_add_oauth_session_table.py
index b1930e6389..264ce13b41 100644
--- a/backend/open_webui/migrations/versions/38d63c18f30f_add_oauth_session_table.py
+++ b/backend/open_webui/migrations/versions/38d63c18f30f_add_oauth_session_table.py
@@ -20,6 +20,31 @@ depends_on: Union[str, Sequence[str], None] = None
 
 
 def upgrade() -> None:
+    # Ensure 'id' column in 'user' table is unique and primary key (ForeignKey constraint)
+    inspector = sa.inspect(op.get_bind())
+    columns = inspector.get_columns("user")
+
+    pk_columns = inspector.get_pk_constraint("user")["constrained_columns"]
+    id_column = next((col for col in columns if col["name"] == "id"), None)
+
+    if id_column and not id_column.get("unique", False):
+        unique_constraints = inspector.get_unique_constraints("user")
+        unique_columns = {tuple(u["column_names"]) for u in unique_constraints}
+
+        with op.batch_alter_table("user") as batch_op:
+            # If primary key is wrong, drop it
+            if pk_columns and pk_columns != ["id"]:
+                batch_op.drop_constraint(
+                    inspector.get_pk_constraint("user")["name"], type_="primary"
+                )
+
+            # Add unique constraint if missing
+            if ("id",) not in unique_columns:
+                batch_op.create_unique_constraint("uq_user_id", ["id"])
+
+            # Re-create correct primary key
+            batch_op.create_primary_key("pk_user_id", ["id"])
+
     # Create oauth_session table
     op.create_table(
         "oauth_session",