PostgreSQL

The PostgreSQL data source connector connects Prisma ORM to a PostgreSQL database server.

By default, the PostgreSQL connector contains a database driver responsible for connecting to your database. You can use a driver adapter (Preview) to connect to your database using a JavaScript database driver from Prisma Client.

To connect to a PostgreSQL database server, you need to configure a datasource block in your Prisma schema:

datasource db {

  provider = "postgresql"

}

The datasource block specifies the postgresql data source connector.

In Prisma ORM 7, the database connection URL is configured in prisma.config.ts:

import { defineConfig, env } from "prisma/config";

import "dotenv/config";

export default defineConfig({

  schema: "prisma/schema.prisma",

  datasource: {

    url: env("DATABASE_URL"),

  },

});

This configuration uses an environment variable to provide the database connection URL.

As of v5.4.0, you can use Prisma ORM with database drivers from the JavaScript ecosystem (instead of using Prisma ORM's built-in drivers). You can do this by using a driver adapter.

For PostgreSQL, node-postgres (pg) is one of the most popular drivers in the JavaScript ecosystem. It can be used with any PostgreSQL database that's accessed via TCP.

This section explains how you can use it with Prisma ORM and the @prisma/adapter-pg driver adapter.

First, install Prisma ORM's driver adapter for pg:

bun add @prisma/adapter-pg@6.19.3

pnpm add @prisma/adapter-pg@6.19.3

yarn add @prisma/adapter-pg@6.19.3

npm install @prisma/adapter-pg@6.19.3

Now, when you instantiate Prisma Client, you need to pass an instance of Prisma ORM's driver adapter to the PrismaClient constructor:

import "dotenv/config";

import { PrismaPg } from "@prisma/adapter-pg";

import { PrismaClient } from "../generated/prisma/client";

const connectionString = `${process.env.DATABASE_URL}`;

const adapter = new PrismaPg({ connectionString });

const prisma = new PrismaClient({ adapter });

Notice that this code requires the DATABASE_URL environment variable to be set to your PostgreSQL connection string. You can learn more about the connection string below.

You can specify a PostgreSQL schema by passing in the schema option when instantiating PrismaPg:

const adapter = new PrismaPg({ connectionString }, { schema: "myPostgresSchema" });

Prisma ORM follows the connection URL format specified by PostgreSQL's official guidelines, but does not support all arguments and includes additional arguments such as schema. A PostgreSQL connection URL has these components:

Here is an example of the structure of the base URL and the path using placeholder values in uppercase letters:

postgresql://USER:PASSWORD@HOST:PORT/DATABASE

The following components make up the base URL of your database, they are always required:

A connection URL can also take arguments. Here is the same example from above with placeholder values in uppercase letters for three arguments:

postgresql://USER:PASSWORD@HOST:PORT/DATABASE?KEY1=VALUE&KEY2=VALUE&KEY3=VALUE

The following arguments can be used:

As an example, if you want to connect to a schema called myschema, set the connection pool size to 5 and configure a timeout for queries of 3 seconds. You can use the following arguments:

postgresql://USER:PASSWORD@HOST:PORT/DATABASE?schema=myschema&connection_limit=5&socket_timeout=3

You can add various parameters to the connection URL if your database server uses SSL. The possible parameters are:

• sslmode=(disable|prefer|require):

  • prefer (default): Prefer TLS if possible, accept plain text connections.
  • disable: Do not use TLS.
  • require: Require TLS or fail if not possible.

• sslcert=<PATH>: Path to the server certificate. This is the root certificate used by the database server to sign the client certificate. You need to provide this if the certificate doesn't exist in the trusted certificate store of your system. For Google Cloud this likely is server-ca.pem. Certificate paths are resolved relative to the ./prisma folder

• sslidentity=<PATH>: Path to the PKCS12 certificate database created from client cert and key. This is the SSL identity file in PKCS12 format which you will generate using the client key and client certificate. It combines these two files in a single file and secures them via a password (see next parameter). You can create this file using your client key and client certificate by using the following command (using openssl):

  openssl pkcs12 -export -out client-identity.p12 -inkey client-key.pem -in client-cert.pem

• sslpassword=<PASSWORD>: Password that was used to secure the PKCS12 file. The openssl command listed in the previous step will ask for a password while creating the PKCS12 file, you will need to provide that same exact password here.

• sslaccept=(strict|accept_invalid_certs):

  • strict: Any missing value in the certificate will lead to an error. For Google Cloud, especially if the database doesn't have a domain name, the certificate might miss the domain/IP address, causing an error when connecting.
  • accept_invalid_certs (default): Bypass this check. Be aware of the security consequences of this setting.

Your database connection URL will look similar to this:

postgresql://USER:PASSWORD@HOST:PORT/DATABASE?sslidentity=client-identity.p12&sslpassword=mypassword&sslcert=rootca.cert

To connect to your PostgreSQL database via sockets, you must add a host field as a query parameter to the connection URL (instead of setting it as the host part of the URI). The value of this parameter then must point to the directory that contains the socket, e.g.: postgresql://USER:PASSWORD@localhost/database?host=/var/run/postgresql/

Note that localhost is required, the value itself is ignored and can be anything.

Note: You can find additional context in this GitHub issue.

These two tables show the type mapping between PostgreSQL and Prisma schema. First how Prisma ORM scalar types are translated into PostgreSQL database column types, and then how PostgreSQL database column types relate to Prisma ORM scalar and native types.

Alternatively, see Prisma schema reference for type mappings organized by Prisma type.

The PostgreSQL connector maps the scalar types from the Prisma ORM data model as follows to database column types:

• When introspecting a PostgreSQL database, the database types are mapped to Prisma ORM types according to the following table.
• When creating a migration or prototyping your schema the table is also used - in the other direction.

Introspection adds native database types that are not yet supported as Unsupported fields:

model Device {

  id   Int                   @id @default(autoincrement())

  name String

  data Unsupported("circle")

}

A prepared statement is a feature that can be used to optimize performance. A prepared statement is parsed, compiled, and optimized only once and then can be executed directly multiple times without the overhead of parsing the query again.

By caching prepared statements, Prisma Client's query engine does not repeatedly compile the same query which reduces database CPU usage and query latency.

For example, here is the generated SQL for two different queries made by Prisma Client:

SELECT * FROM user WHERE name = "John";

SELECT * FROM user WHERE name = "Brenda";

The two queries after parameterization will be the same, and the second query can skip the preparing step, saving database CPU and one extra roundtrip to the database. Query after parameterization:

SELECT * FROM user WHERE name = $1

Every database connection maintained by Prisma Client has a separate cache for storing prepared statements. The size of this cache can be tweaked with the statement_cache_size parameter in the connection string. By default, Prisma Client caches 100 statements per connection.

Due to the nature of pgBouncer, if the pgbouncer parameter is set to true, the prepared statement cache is automatically disabled for that connection.