ORM options (Prisma, Drizzle) in Deno - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an ORM and why is it useful in Deno projects?

An ORM (Object-Relational Mapping) helps you work with databases using code objects instead of raw queries. It makes database tasks easier and safer by translating code into database commands automatically.

beginner

What is Prisma in the context of Deno?

Prisma is a modern ORM that supports Deno. It provides a type-safe way to interact with databases, auto-generates queries, and helps manage database schemas with ease.

intermediate

What is Drizzle ORM and how does it differ from Prisma?

Drizzle ORM is a lightweight and flexible ORM for Deno that focuses on simplicity and type safety. Compared to Prisma, it is more minimal and can be easier to customize for small to medium projects.

intermediate

Name one advantage of using Prisma over Drizzle ORM in Deno.

Prisma offers powerful schema migrations and a rich ecosystem with tools like Prisma Studio for database management, which can speed up development in complex projects.

intermediate

How does Drizzle ORM ensure type safety in Deno applications?

Drizzle ORM uses TypeScript types to ensure that database queries and results match expected shapes, reducing runtime errors and improving developer confidence.

Which ORM is known for its rich ecosystem and schema migration tools in Deno?

A Prisma

B Drizzle

C Sequelize

D TypeORM

Prisma provides powerful schema migrations and a rich set of tools, making it popular for complex Deno projects.

What is a key feature of Drizzle ORM in Deno?

A Heavyweight with many dependencies

B Lightweight and flexible with strong type safety

C Only supports SQL Server

D Requires manual query writing only

Drizzle ORM is designed to be lightweight and flexible, focusing on type safety and simplicity.

In Deno, why use an ORM like Prisma or Drizzle instead of raw SQL queries?

A To write more complex SQL queries manually

B To make the app slower

C To avoid writing any database code

D To simplify database interactions and reduce errors

ORMs simplify database work by letting you use code objects, reducing errors and speeding up development.

Which ORM would be better for a small Deno project needing minimal setup?

A Drizzle

B Entity Framework

C Hibernate

D Prisma

Drizzle ORM is lightweight and easy to set up, making it suitable for small projects.

What language feature do both Prisma and Drizzle leverage in Deno for safer database code?

A JavaScript callbacks

B CSS styling

C TypeScript type safety

D HTML templates

Both ORMs use TypeScript's type system to ensure safer and more predictable database interactions.

Explain the main differences between Prisma and Drizzle ORM when used in Deno projects.

Think about project size, features, and developer experience.

Describe why using an ORM like Prisma or Drizzle can improve your Deno app development.

Consider how ORMs help with code and database interaction.

Practice

1. What is the main purpose of using an ORM like Prisma or Drizzle in a Deno project?

easy

A. To manage server configurations and deployments

B. To create user interfaces for web applications

C. To write low-level network protocols

D. To interact with databases using simple and safe code instead of raw SQL

Solution

1. Step 1: Understand what ORM stands for

   ORM means Object-Relational Mapping, which helps connect code with databases easily.

2. Step 2: Identify ORM's role in Deno projects

   ORMs like Prisma and Drizzle let you write code to manage database data without writing raw SQL queries.

3. Final Answer:

   To interact with databases using simple and safe code instead of raw SQL -> Option D

4. Quick Check:

   ORM = Simple database code [OK]

Hint: ORMs simplify database work by hiding raw SQL [OK]

Common Mistakes:

• Confusing ORM with UI libraries
• Thinking ORM manages server setup
• Assuming ORM handles network protocols

2. Which of the following is the correct way to import Prisma Client in a Deno project?

easy

A. import { PrismaClient } from "@prisma/client";

B. import PrismaClient from "prisma/client";

C. const PrismaClient = require("@prisma/client");

D. import prisma from "deno-prisma";

Solution

1. Step 1: Recall Prisma Client import syntax

   Prisma Client is imported using ES module syntax with curly braces from "@prisma/client".

2. Step 2: Check each option for correctness

   import { PrismaClient } from "@prisma/client"; uses correct ES import syntax. import PrismaClient from "prisma/client"; misses curly braces. const PrismaClient = require("@prisma/client"); uses CommonJS require which is not used in Deno. import prisma from "deno-prisma"; uses a wrong package name.

3. Final Answer:

   import { PrismaClient } from "@prisma/client"; -> Option A

4. Quick Check:

   Prisma import uses curly braces and correct package [OK]

Hint: Prisma uses named import from "@prisma/client" [OK]

Common Mistakes:

• Using require() instead of import
• Missing curly braces in import
• Wrong package names

3. Given this Drizzle code snippet in Deno, what will be the output if the database has two users named 'Alice' and 'Bob'?

const users = await db.select().from(usersTable);
console.log(users.map(u => u.name));

medium

A. [{name: "Alice"}, {name: "Bob"}]

B. undefined

C. ["Alice", "Bob"]

D. SyntaxError

Solution

1. Step 1: Understand the select query

   The code selects all rows from usersTable and stores them in users array.

2. Step 2: Map user objects to their names

   users.map(u => u.name) creates a new array with only the name values from each user object.

3. Final Answer:

   ["Alice", "Bob"] -> Option C

4. Quick Check:

   Mapping user objects to names returns array of names [OK]

Hint: Mapping extracts just the names from user objects [OK]

Common Mistakes:

• Expecting full objects instead of names array
• Confusing map output with original array
• Assuming syntax error due to async

4. You wrote this Prisma query in Deno but get an error: const users = await prisma.user.findMany(). What is the likely cause?

medium

A. You must import Drizzle instead of Prisma

B. You forgot to instantiate PrismaClient before using it

C. You need to use raw SQL instead of Prisma queries

D. The findMany method does not exist in Prisma

Solution

1. Step 1: Check PrismaClient usage

   Before calling prisma.user.findMany(), you must create an instance: const prisma = new PrismaClient();

2. Step 2: Understand error cause

   If prisma is not instantiated, calling findMany() causes an error because prisma is undefined.

3. Final Answer:

   You forgot to instantiate PrismaClient before using it -> Option B

4. Quick Check:

   Instantiate PrismaClient before queries [OK]

Hint: Always create PrismaClient instance before queries [OK]

Common Mistakes:

• Assuming findMany doesn't exist
• Trying raw SQL instead of ORM methods
• Mixing Prisma and Drizzle imports

5. You want to use Drizzle ORM in Deno to insert a new user only if the username is not empty and then fetch all users. Which code snippet correctly applies this logic?

hard

A. if (username) {
await db.insert(usersTable).values({ name: username });
}
const allUsers = await db.select().from(usersTable);

B. await db.insert(usersTable).values({ name: username });
if (username) {
const allUsers = await db.select().from(usersTable);
}

C. const allUsers = await db.select().from(usersTable);
if (username) {
await db.insert(usersTable).values({ name: username });
}

D. await db.insert(usersTable).values({ name: username });
const allUsers = await db.select().from(usersTable);

Solution

1. Step 1: Check condition before insert

   We must insert only if username is not empty, so the insert is inside the if (username) block.

2. Step 2: Fetch all users after conditional insert

   After the conditional insert, we fetch all users with db.select().from(usersTable) and store in allUsers.

3. Final Answer:

   if (username) { await db.insert(usersTable).values({ name: username }); } const allUsers = await db.select().from(usersTable); -> Option A

4. Quick Check:

   Insert only if username, then fetch all users [OK]

Hint: Put insert inside if, then select all users [OK]

Common Mistakes:

• Inserting without checking username
• Fetching users before insert
• Fetching users inside the if block