a few minor tweaks for drivers

src/metabase/driver/generic_sql/query_processor.clj

@@ -142,7 +142,7 @@
   [table-id]
   {:pre [(integer? table-id)]
    :post [(map? %)]}
-  (let [{:keys [korma-entity]} (sel :one Table :id table-id)]
+  (when-let [{:keys [korma-entity]} (sel :one Table :id table-id)]
     @korma-entity))
 
 (defn- field-id->kw

src/metabase/driver/h2/sync.clj

@@ -6,8 +6,10 @@
 (def column->base-type
   "Map of H2 Column types -> Field base types. (Add more mappings here as needed)"
   {:BIGINT :BigIntegerField
+   :DATE :DateField
    :DOUBLE :FloatField
    :INTEGER :IntegerField
+   :TIMESTAMP :DateTimeField
    :VARCHAR :TextField})
 
 (defmethod driver/sync-tables :h2 [database]

src/metabase/driver/util.clj

@@ -12,5 +12,6 @@
    Would load `metabase.driver.postgres.metadata` for a `Database` whose `:engine` was `:postgres`."
   [impl-namespace]
   (fn [{:keys [engine]}]
+    {:pre [engine]}
     (require (symbol (str "metabase.driver." engine "." impl-namespace)))
     (keyword engine)))