How to fix Error: P4001 The introspected database was empty in Prisma

Connect to your database using a database client and confirm tables exist:

For PostgreSQL:

psql <connection_string>
\dt

For MySQL:

mysql -u <user> -p <database>
SHOW TABLES;

For SQL Server:

SELECT * FROM INFORMATION_SCHEMA.TABLES;

If no tables exist, you need to either create your schema manually or migrate from another source.

Verify the connection URL in your .env file or schema.prisma:

DATABASE_URL="postgresql://user:password@localhost:5432/mydb"

Common mistakes:
- Pointing to a different database than intended
- Using a test/development database that's empty
- Typo in the database name

For Supabase users, ensure you're using the direct connection string (port 5432) not the pooled connection string (port 6543).

The database user must have permissions to view tables and schemas. Test by connecting with the same credentials:

For PostgreSQL:

-- Check what schemas you can see
SELECT nspname FROM pg_namespace;

-- Check tables in public schema
SELECT tablename FROM pg_tables WHERE schemaname = 'public';

If you're using a limited user, try connecting as a superuser (like postgres) temporarily to verify tables exist. If they do, your user needs USAGE and SELECT privileges on the schema:

GRANT USAGE ON SCHEMA public TO your_user;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO your_user;

SQL Server requires explicit schema specification in the connection URL:

DATABASE_URL="sqlserver://localhost:1433;database=mydb;schema=dbo;user=sa;password=yourPassword"

The schema=dbo parameter tells Prisma which schema to introspect. Without it, Prisma may not find your tables even if they exist.

You can also use the schemas preview feature for multi-schema support:

generator client {
  provider        = "prisma-client-js"
  previewFeatures = ["multiSchema"]
}

datasource db {
  provider = "sqlserver"
  url      = env("DATABASE_URL")
  schemas  = ["dbo", "custom"]
}

If you're working with a genuinely empty database and want to use introspection, create at least one table first:

For PostgreSQL:

CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  email VARCHAR(255) UNIQUE NOT NULL,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

For MySQL:

CREATE TABLE users (
  id INT AUTO_INCREMENT PRIMARY KEY,
  email VARCHAR(255) UNIQUE NOT NULL,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

Then run prisma db pull again. Prisma will generate a model for the table.

If you're building a new application from scratch, don't use introspection. Instead, define your schema in schema.prisma and let Prisma create the tables:

model User {
  id        Int      @id @default(autoincrement())
  email     String   @unique
  createdAt DateTime @default(now())
}

Then run:

# Create migration and apply to database
npx prisma migrate dev --name init

# Or just push schema changes without migrations
npx prisma db push

Introspection is for adding Prisma to existing databases, not creating new ones.