Add function to check whether valueset data exists in the DB (#152)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

query-connector/src/app/database-service.ts

@@ -605,3 +605,23 @@ export async function getConditionsData() {
     conditionIdToNameMap,
   } as const;
 }
+
+/**
+ * Checks the database to see if data has been loaded into the valuesets table by
+ * estmating the number of rows in the table. If the estimated count is greater than
+ * 0, the function returns true, otherwise false.
+ * @returns A boolean indicating whether the valuesets table has data.
+ */
+export async function checkDBForData() {
+  const query = `
+    SELECT reltuples AS estimated_count
+    FROM pg_class
+    WHERE relname = 'valuesets';
+  `;
+  const result = await dbClient.query(query);
+
+  // Return true if the estimated count > 0, otherwise false
+  return (
+    result.rows.length > 0 && parseFloat(result.rows[0].estimated_count) > 0
+  );
+}

query-connector/src/app/fhir-servers.ts

@@ -90,7 +90,6 @@ class FHIRClient {
 
   async get(path: string): Promise<Response> {
     try {
-      console.log("FHIR Server: ", this.hostname);
       return fetch(this.hostname + path, this.init);
     } catch (error) {
       console.error(error);

query-connector/src/db-creation.ts

@@ -3,6 +3,7 @@
 import { ersdToDibbsConceptMap, ErsdConceptType } from "@/app/constants";
 import { Bundle, BundleEntry, ValueSet } from "fhir/r4";
 import {
+  checkDBForData,
   checkValueSetInsertion,
   getERSD,
   getVSACValueSet,
@@ -178,10 +179,17 @@ async function fetchBatchValueSetsFromVsac(oidData: OidData, batchSize = 100) {
  * the eRSD, extracting OIDs, then inserting valuesets into the DB.
  */
 export async function createDibbsDB() {
-  const ersdOidData = await getOidsFromErsd();
-  if (ersdOidData) {
-    await fetchBatchValueSetsFromVsac(ersdOidData);
+  // Check if the DB already contains valuesets
+  const dbHasData = await checkDBForData();
+
+  if (!dbHasData) {
+    const ersdOidData = await getOidsFromErsd();
+    if (ersdOidData) {
+      await fetchBatchValueSetsFromVsac(ersdOidData);
+    } else {
+      console.error("Could not load eRSD, aborting DIBBs DB creation");
+    }
   } else {
-    console.error("Could not load eRSD, aborting DIBBs DB creation");
+    console.log("Database already has data; skipping DIBBs DB creation.");
   }
 }