Microsoft SQL Server

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


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

1datasource db {
2 provider = "sqlserver"
3 url = env("DATABASE_URL")

The fields passed to the datasource block are:

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:


Using integrated security (Windows only)

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


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


Using SQL Browser to connect to a named instance

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



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.

Type mapping between Microsoft SQL Server to Prisma schema

For type mappings organized by Prisma 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 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:

1CREATE DEFAULT catcat AS 'musti';
5 name NVARCHAR(1000)
8sp_bindefault 'catcat', '';

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

3 name NVARCHAR(1000) CONSTRAINT DF_cat_name DEFAULT 'musti'

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

1model cats {
2 id Int @id @default(autoincrement())
3 name String? @default("musti")

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

1model cats {
2 id Int @id @default(autoincrement())
3 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)

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