Instantiate a single instance of PrismaClient

src/app/api/listings/route.js

-import { PrismaClient } from '@prisma/client';
+import { prisma } from '../../db/client'
 import { NextResponse } from 'next/server';
 
-const prisma = new PrismaClient();
-
 export async function GET() {
     const listings = await prisma.post.findMany()
     return NextResponse.json(listings)

src/app/api/post/route.js

-import { PrismaClient } from '@prisma/client';
+import { prisma } from '../../db/client'
 import { NextResponse } from 'next/server';
 
-const prisma = new PrismaClient();
-
 export async function GET() {
   const post = await prisma.post.findFirst({
     select: {

src/app/api/student/route.js

-import { PrismaClient } from '@prisma/client';
+import { prisma } from '../../db/client'
 import { NextResponse } from 'next/server';
 
-const prisma = new PrismaClient();
-
 export async function GET() {
   const student = await prisma.student.findFirst();
   return NextResponse.json(student);

src/app/db/client.js

+import { PrismaClient } from '@prisma/client'
+
+export const prisma =
+  globalForPrisma.prisma ??
+  new PrismaClient({
+    log: ['query'],
+  })
+
+if (process.env.NODE_ENV !== 'production') globalForPrisma.prisma = prisma