refactor: simplify database connection setup and remove global variab…

…le usage

src/features/codante-apis/senator-expenses/db/db.ts

@@ -1,20 +1,13 @@
 import { drizzle } from 'drizzle-orm/mysql2';
 import mysql from 'mysql2/promise';
-
-declare global {
-  var _db: ReturnType<typeof drizzle> | undefined;
-}
+import * as schema from './schema';
 
 const poolConnection = mysql.createPool({
   user: process.env.DATABASE_USER_SENATOR_EXPENSES,
   password: process.env.DATABASE_PASSWORD_SENATOR_EXPENSES,
   database: process.env.DATABASE_SENATOR_EXPENSES,
 });
 
-const db = globalThis._db || drizzle(poolConnection);
-
-if (process.env.NODE_ENV !== 'production') {
-  globalThis._db = db;
-}
+const db = drizzle(poolConnection, { schema, mode: 'default' });
 
 export { db, poolConnection };