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Microsoft SQL Server

The Microsoft SQL Server data source connector connects Prisma ORM to a Microsoft SQL Server database server.

Example​

To connect to a Microsoft SQL Server database, you need to configure a datasource block in your Prisma schema:

schema.prisma
datasource db {
  provider = "sqlserver"
  url      = env("DATABASE_URL")
}

The fields passed to the datasource block are:

Using the node-mssql driver​

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 SQLite, node-mssql is one of the most popular drivers in the JavaScript ecosystem.

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

1. Enable the driverAdapters Preview feature flag​

Since driver adapters are currently in Preview, you need to enable its feature flag on the datasource block in your Prisma schema:

schema.prisma
generator client {
  provider        = "prisma-client-js"
  previewFeatures = ["driverAdapters"]
}

datasource db {
  provider = "sqlserver"
  url      = env("DATABASE_URL")
}

Once you have added the feature flag to your schema, re-generate Prisma Client:

npx prisma generate

2. Install the dependencies​

Next, install Prisma ORM's driver adapter for node-mssql:

npm install @prisma/adapter-mssql

3. Instantiate Prisma Client using the driver adapter​

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

import { PrismaMssql } from '@prisma/adapter-mssql'
import { PrismaClient } from '@prisma/client'

const config = {
  server: 'localhost',
  port: 1433,
  database: 'mydb',
  user: 'sa',
  password: 'mypassword',
  options: {
    encrypt: true, // Use this if you're on Windows Azure
    trustServerCertificate: true, // Use this if you're using self-signed certificates
  },
}

const adapter = new PrismaMssql(config)
const prisma = new PrismaClient({ adapter })

Connection details​

The connection URL used to connect to an Microsoft SQL Server database follows the JDBC standard.

The following example uses SQL authentication (username and password) with an enabled TLS encrypted connection:

sqlserver://HOST[:PORT];database=DATABASE;user=USER;password=PASSWORD;encrypt=true
warning

Note: If you are using any of the following characters in your connection string, you will need to escape them.

:\=;/[]{}  # these are characters that will need to be escaped

To escape these characters, use curly braces {} around values that contain special characters. As an example:

sqlserver://HOST[:PORT];database=DATABASE;user={MyServer/MyUser};password={ThisIsA:SecurePassword;};encrypt=true

Arguments​

Argument nameRequiredDefaultComments
  • database
  • initial catalog
NomasterThe database to connect to.
  • username
  • user
  • uid
  • userid
No - see CommentsSQL Server login (such as sa) or a valid Windows (Active Directory) username if integratedSecurity is set to true (Windows only).
  • password
  • pwd
No - see CommentsPassword for SQL Server login or Windows (Active Directory) username if integratedSecurity is set to true (Windows only).
encryptNotrueConfigures whether to use TLS all the time, or only for the login procedure, possible values: true (use always), false (only for login credentials).
integratedSecurityNoEnables Windows authentication (integrated security), possible values: true, false, yes, no. If set to true or yes and username and password are present, login is performed through Windows Active Directory. If login details are not given via separate arguments, the current logged in Windows user is used to login to the server.
connectionLimitNonum_cpus * 2 + 1Maximum size of the connection pool
connectTimeoutNo5Maximum number of seconds to wait for a new connection
schemaNodboAdded as a prefix to all the queries if schema name is not the default.
  • loginTimeout
  • connectTimeout
  • connectionTimeout
NoNumber of seconds to wait for login to succeed.
socketTimeoutNoNumber of seconds to wait for each query to succeed.
isolationLevelNoSets transaction isolation level.
poolTimeoutNo10Maximum number of seconds to wait for a new connection from the pool. If all connections are in use, the database will return a PoolTimeout error after waiting for the given time.
  • ApplicationName
  • Application Name
(case insensitive)		NoSets the application name for the connection. Since version 2.28.0.
trustServerCertificateNofalseConfigures whether to trust the server certificate.
trustServerCertificateCANoA path to a certificate authority file to be used instead of the system certificates to authorize the server certificate. Must be either in pem, crt or der format. Cannot be used together with trustServerCertificate parameter.

Using integrated security (Windows only)​

The following example uses the currently logged in Windows user to log in to Microsoft SQL Server:

sqlserver://localhost:1433;database=sample;integratedSecurity=true;trustServerCertificate=true;

The following example uses a specific Active Directory user to log in to Microsoft SQL Server:

sqlserver://localhost:1433;database=sample;integratedSecurity=true;username=prisma;password=aBcD1234;trustServerCertificate=true;

Connect to a named instance​

The following example connects to a named instance of Microsoft SQL Server (mycomputer\sql2019) using integrated security:

sqlserver://mycomputer\sql2019;database=sample;integratedSecurity=true;trustServerCertificate=true;

Type mapping between Microsoft SQL Server to Prisma schema​

For type mappings organized by Prisma ORM type, refer to the Prisma schema reference documentation.

Supported versions​

See Supported databases.

Limitations and known issues​

Prisma Migrate caveats​

Prisma Migrate is supported in 2.13.0 and later with the following caveats:

Database schema names​

SQL Server does not have an equivalent to the PostgreSQL SET search_path command familiar from PostgreSQL. This means that when you create migrations, you must define the same schema name in the connection URL that is used by the production database. For most of the users this is dbo (the default value). However, if the production database uses another schema name, all the migration SQL must be either edited by hand to reflect the production or the connection URL must be changed before creating migrations (for example: schema=name).

Cyclic references​

Circular references can occur between models when each model references another, creating a closed loop. When using a Microsoft SQL Server database, Prisma ORM will show a validation error if the referential action on a relation is set to something other than NoAction.

See Special rules for referential actions in SQL Server for more information.

Destructive changes​

Certain migrations will cause more changes than you might expect. For example:

  • Adding or removing autoincrement(). This cannot be achieved by modifying the column, but requires recreating the table (including all constraints, indices, and foreign keys) and moving all data between the tables.
  • Additionally, it is not possible to delete all the columns from a table (possible with PostgreSQL or MySQL). If a migration needs to recreate all table columns, it will also re-create the table.

Shared default values are not supported​

In some cases, user might want to define default values as shared objects:

default_objects.sql
CREATE DEFAULT catcat AS 'musti';

CREATE TABLE cats (
    id INT IDENTITY PRIMARY KEY,
    name NVARCHAR(1000)
);

sp_bindefault 'catcat', 'dbo.cats.name';

Using the stored procedure sp_bindefault, the default value catcat can be used in more than one table. The way Prisma ORM manages default values is per table:

default_per_table.sql
CREATE TABLE cats (
    id INT IDENTITY PRIMARY KEY,
    name NVARCHAR(1000) CONSTRAINT DF_cat_name DEFAULT 'musti'
);

The last example, when introspected, leads to the following model:

schema.prisma
model cats {
  id   Int     @id @default(autoincrement())
  name String? @default("musti")
}

And the first doesn't get the default value introspected:

schema.prisma
model cats {
  id   Int     @id @default(autoincrement())
  name String?
}

If using Prisma Migrate together with shared default objects, changes to them must be done manually to the SQL.

Data model limitations​

Cannot use column with UNIQUE constraint and filtered index as foreign key​

Microsoft SQL Server only allows one NULL value in a column that has a UNIQUE constraint. For example:

  • A table of users has a column named license_number
  • The license_number field has a UNIQUE constraint
  • The license_number field only allows one NULL value

The standard way to get around this issue is to create a filtered unique index that excludes NULL values. This allows you to insert multiple NULL values. If you do not create an index in the database, you will get an error if you try to insert more than one null value into a column with Prisma Client.

However, creating an index makes it impossible to use license_number as a foreign key in the database (or a relation scalar field in corresponding Prisma Schema)

Raw query considerations​

Raw queries with String @db.VarChar(n) fields / VARCHAR(N) columns​

String query parameters in raw queries are always encoded to SQL Server as NVARCHAR(4000) (if your String length is <= 4000) or NVARCHAR(MAX). If you compare a String query parameter to a column of type String @db.VarChar(N)/VARCHAR(N), this can lead to implicit conversion on SQL Server which affects your index performance and can lead to high CPU usage.

Here is an example:

model user {
  id Int @id
  name String @db.VarChar(40)
}

This query would be affected:

await prisma.$queryRaw`SELECT * FROM user WHERE name = ${"John"}`

To avoid the problem, we recommend you always manually cast your String query parameters to VARCHAR(N) in the raw query:

await prisma.$queryRaw`SELECT * FROM user WHERE name = CAST(${"John"} AS VARCHAR(40))`

This enables SQL Server to perform a Clustered Index Seek instead of a Clustered Index Scan.