diff --git a/db/schema.sql b/db/schema.sql
index ac0fa2f..877ce65 100644
--- a/db/schema.sql
+++ b/db/schema.sql
@@ -105,26 +105,14 @@ CREATE TABLE dict.facet__concept_node (
     CONSTRAINT fk_facet FOREIGN KEY (FACET_ID) REFERENCES dict.facet(FACET_ID),
     CONSTRAINT fk_concept_node FOREIGN KEY (CONCEPT_NODE_ID) REFERENCES dict.concept_node(CONCEPT_NODE_ID)
 );
-
--- Commenting out because I don't remember what these do.
-
---CREATE TABLE dict.harmonized_concept_node (
---    HARMONIZED_CONCEPT_NODE_ID INT GENERATED BY DEFAULT AS IDENTITY,
---    NAME VARCHAR(512) NOT NULL,
---    DISPLAY VARCHAR(512) NOT NULL,
---    CONCEPT_PATH VARCHAR(10000) NOT NULL DEFAULT 'INVALID',
---    PARENT_ID INT,
---    PRIMARY KEY (CONCEPT_NODE_ID),
---    CONSTRAINT fk_parent FOREIGN KEY (PARENT_ID) REFERENCES harmonized_CONCEPT_NODE(CONCEPT_NODE_ID)
---);
---CREATE UNIQUE INDEX harmonized_concept_node_concept_path_idx ON harmonized_concept_node(md5(CONCEPT_PATH));
---
---CREATE TABLE dict.harmonized_concept_node__concept_node (
---    HARMONIZED_CONCEPT_NODE__CONCEPT_NODE INT GENERATED BY DEFAULT AS IDENTITY,
---    HARMONIZED_CONCEPT_NODE_ID INT NOT NULL,
---    CONCEPT_NODE_ID INT NOT NULL,
---    PRIMARY KEY (HARMONIZED_CONCEPT_NODE__CONCEPT_NODE),
---    UNIQUE(HARMONIZED_CONCEPT_NODE_ID, CONCEPT_NODE_ID),
---    CONSTRAINT fk_harmonized_CONCEPT_NODE FOREIGN KEY (HARMONIZED_CONCEPT_NODE_ID) REFERENCES harmonized_CONCEPT_NODE(HARMONIZED_CONCEPT_NODE_ID),
---    CONSTRAINT fk_CONCEPT_NODE FOREIGN KEY (CONCEPT_NODE_ID) REFERENCES CONCEPT_NODE(CONCEPT_NODE_ID)
---);
+CREATE TABLE IF NOT EXISTS dict.dataset_harmonization
+(
+    dataset_harmonization_id INT NOT NULL GENERATED BY DEFAULT AS IDENTITY,
+    harmonized_dataset_id INT NOT NULL,
+    source_dataset_id INT NOT NULL,
+    UNIQUE (harmonized_dataset_id, source_dataset_id),
+    CONSTRAINT fk_harmonized_dataset_id FOREIGN KEY (harmonized_dataset_id)
+        REFERENCES dict.dataset (dataset_id),
+    CONSTRAINT fk_source_dataset_id FOREIGN KEY (source_dataset_id)
+        REFERENCES dict.dataset (dataset_id)
+);