diff --git a/deps.edn b/deps.edn
index c3d3ff9..8dd7325 100644
--- a/deps.edn
+++ b/deps.edn
@@ -1,5 +1,6 @@
 {:paths ["src" "lib"]
  :deps {techascent/tech.ml.dataset {:mvn/version "7.026"}
+        cnuernber/dtype-next {:mvn/version "10.111"}
         techascent/tech.ml.dataset.sql {:mvn/version "7.000-beta-52"}
         net.java.dev.jna/jna {:mvn/version "5.13.0"}}
  :aliases
diff --git a/src/tmducken/duckdb/ffi.clj b/src/tmducken/duckdb/ffi.clj
index 0b10ab1..34a7765 100644
--- a/src/tmducken/duckdb/ffi.clj
+++ b/src/tmducken/duckdb/ffi.clj
@@ -480,23 +480,23 @@ all memory associated with the appender.
 
 (defonce blob-def* (delay (dt-struct/define-datatype! :duckdb-blob
                             [{:name :data
-                              :datatype @ptr-dtype*}
+                              :datatype :pointer}
                              {:name :size
                               :datatype :uint64}])))
 
 
 (defonce column-def* (delay (dt-struct/define-datatype! :duckdb-column
                               [{:name :data
-                                :datatype @ptr-dtype*}
+                                :datatype :pointer}
                                {:name :nullmask
-                                :datatype @ptr-dtype*}
+                                :datatype :pointer}
                                ;;duckdb-type
                                {:name :type
                                 :datatype :int32}
                                {:name :name
-                                :datatype @ptr-dtype*}
+                                :datatype :pointer}
                                {:name :internal_data
-                                :datatype @ptr-dtype*}])))
+                                :datatype :pointer}])))
 
 
 (defonce result-def* (delay
@@ -508,11 +508,11 @@ all memory associated with the appender.
                           {:name :rows-changed
                            :datatype :uint64}
                           {:name :columns
-                           :datatype @ptr-dtype*}
+                           :datatype :pointer}
                           {:name :error-message
-                           :datatype @ptr-dtype*}
+                           :datatype :pointer}
                           {:name :internal-data
-                           :datatype @ptr-dtype*}])))
+                           :datatype :pointer}])))
 
 
 
@@ -520,40 +520,40 @@ all memory associated with the appender.
   (delay
     (dt-struct/define-datatype! :duckdb-logical-type
       [{:name :__lglt
-        :datatype @ptr-dtype*}])))
+        :datatype :pointer}])))
 
 
 (defonce data-chunk-def*
   (delay
     (dt-struct/define-datatype! :duckdb-data-chunk
       [{:name :__dtck
-        :datatype @ptr-dtype*}])))
+        :datatype :pointer}])))
 
 
 (defonce vector-def*
   (delay
     (dt-struct/define-datatype! :duckdb-vector
       [{:name :__vec
-        :datatype @ptr-dtype*}])))
+        :datatype :pointer}])))
 
 
 (defonce appender-def*
   (delay
     (dt-struct/define-datatype! :duckdb-appender
       [{:name :__appn
-        :datatype @ptr-dtype*}])))
+        :datatype :pointer}])))
 
 (defonce prepared-statement-def*
   (delay
     (dt-struct/define-datatype! :duckdb-prepared-statement
       [{:name :__prep
-        :datatype @ptr-dtype*}])
+        :datatype :pointer}])
     (dt-struct/define-datatype! :duckdb-extracted-statements
       [{:name :__extrac
-        :datatype @ptr-dtype*}])
+        :datatype :pointer}])
     (dt-struct/define-datatype! :duckdb-pending-result
       [{:name :__pend
-        :datatype @ptr-dtype*}])
+        :datatype :pointer}])
     ))
 
 
diff --git a/test/tmducken/duckdb_test.clj b/test/tmducken/duckdb_test.clj
index 76331e2..838edbc 100644
--- a/test/tmducken/duckdb_test.clj
+++ b/test/tmducken/duckdb_test.clj
@@ -15,6 +15,17 @@
 
 (duckdb/initialize!)
 
+(comment
+  (require '[tech.v3.datatype.ffi.mmodel-jdk21 :as mm])
+  (def cls-def (mm/define-library duckdb-ffi/lib-fns nil nil))
+  (def lib-path (str (java.nio.file.Paths/get (System/getenv "DUCKDB_HOME")
+                                              (into-array String [(System/mapLibraryName "duckdb")]))))
+  (def sym (mm/load-library lib-path))
+  (def inst (tech.v3.datatype.ffi/instantiate-library cls-def sym))
+  (tech.v3.datatype.ffi/library-singleton-set-instance! duckdb-ffi/lib inst)
+  )
+
+
 (def db* (delay (duckdb/initialize!)
                 (duckdb/open-db)))