Use last field of a compound PK when setting auto ids

Author: gheckenbach

lapis/db/mysql/model.lua

@@ -136,8 +136,12 @@ do
     local res = db.insert(self:table_name(), values, self:primary_keys())
     if res then
       local new_id = res.last_auto_id or res.insert_id
-      if not values[self.primary_key] and new_id and new_id ~= 0 then
-        values[self.primary_key] = new_id
+      local pk = self.primary_key
+      if type(pk) == "table" then
+        pk = pk[#pk]
+      end
+      if not values[pk] and new_id and new_id ~= 0 then
+        values[pk] = new_id
       end
       return self:load(values)
     else

lapis/db/mysql/model.moon

@@ -33,8 +33,12 @@ class Model extends BaseModel
       -- either luasql (field res.last_auto_id) or
       -- lua-resty-mysql (field res.insert_id) and
       new_id = res.last_auto_id or res.insert_id
-      if not values[@primary_key] and new_id and new_id != 0
-        values[@primary_key] = new_id
+      pk = @primary_key
+      -- In a compound primary key, the auto_increment field must be last.
+      if type(pk) == "table"
+        pk = pk[#pk]
+      if not values[pk] and new_id and new_id != 0
+        values[pk] = new_id
       @load values
     else
       nil, "Failed to create #{@__name}"