wip: display nested object as columns

src/metabase/driver/crate.clj

@@ -4,7 +4,9 @@
             [metabase.driver :as driver]
             [metabase.driver.crate.util :as crate-util]
             [metabase.driver.generic-sql :as sql]
-            [metabase.util :as u]))
+            [metabase.util :as u]
+            [clojure.tools.logging :as log])
+  (:import (java.sql DatabaseMetaData)))
 
 (def ^:private ^:const column->base-type
   "Map of Crate column types -> Field base types
@@ -55,6 +57,40 @@
 (defn- string-length-fn [field-key]
   (hsql/call :char_length field-key))
 
+(defn- describe-table-fields
+  [database, driver, {:keys [schema name]}]
+  (set (doseq [{column_name :column_name, type_name :type_name}
+             (jdbc/query
+                 (sql/db->jdbc-connection-spec database)
+                 [(format "select column_name, data_type as type_name
+                  from information_schema.columns
+                  where table_name like '%s' and table_schema like '%s'" name schema)])]
+          (merge {:name      column_name
+                 :custom    {:column-type type_name}
+                 :base-type (or (column->base-type driver (keyword type_name))
+                                (do (log/warn (format "Don't know how to map column type '%s' to a Field base_type, falling back to :type/*." type_name))
+                                    :type/*))}))))
+
+(defn- add-table-pks
+  [^DatabaseMetaData metadata, table]
+  (let [pks (->> (.getPrimaryKeys metadata nil nil (:name table))
+                 jdbc/result-set-seq
+                 (mapv :column_name)
+                 set)]
+    (update table :fields (fn [fields]
+                            (set (for [field fields]
+                                   (if-not (contains? pks (:name field))
+                                     field
+                                     (assoc field :pk? true))))))))
+
+(defn- describe-table [driver database table]
+  (sql/with-metadata [metadata driver database]
+                 (->> (assoc (select-keys table [:name :schema]) :fields (describe-table-fields database driver table))
+                      ;; find PKs and mark them
+                      (add-table-pks metadata))))
+
+(defn- field->alias [field]
+  (str \" (name field) \"))
 
 (defrecord CrateDriver []
   clojure.lang.Named
@@ -65,6 +101,7 @@
   (merge (sql/IDriverSQLDefaultsMixin)
          {:can-connect?   (u/drop-first-arg can-connect?)
           :date-interval  crate-util/date-interval
+          :describe-table describe-table
           :details-fields (constantly [{:name         "hosts"
                                         :display-name "Hosts"
                                         :default      "localhost:5432"}])
@@ -75,6 +112,8 @@
           :column->base-type         (u/drop-first-arg column->base-type)
           :string-length-fn          (u/drop-first-arg string-length-fn)
           :date                      crate-util/date
+          :quote-style               :ansi
+          :field->alias              (u/drop-first-arg field->alias)
           :unix-timestamp->timestamp crate-util/unix-timestamp->timestamp
           :current-datetime-fn       (constantly now)}))