Views

Database views allow you to name and store queries. In relational databases, views are stored SQL queries that might include columns in multiple tables, or calculated values such as aggregates. In MongoDB, views are queryable objects where the contents are defined by an aggregation pipeline on other collections.

The views preview feature allows you to represent views in your Prisma schema with the view keyword. To use views in Prisma ORM, follow these steps:

1. Enable the views preview feature
2. Create a view in the underlying database, either directly or as a manual addition to a Prisma Migrate migration file, or use an existing view
3. Represent the view in your Prisma schema
4. Query the view in Prisma Client

:::warning

Support for views is currently a Preview feature. You can add a view to your Prisma schema with the view keyword or introspect the views in your database schema with db pull. You cannot yet apply views in your schema to your database with Prisma Migrate and db push unless the changes are added manually to your migration file using the --create-only flag.

For updates on progress with this feature, follow our GitHub issue.

:::

Enable the views preview feature

Support for views is currently in an early preview. To enable the views preview feature, add the views feature flag to the previewFeatures field of the generator block in your Prisma Schema:

generator client {
  provider        = "prisma-client"
  output          = "./generated"
  previewFeatures = ["views"] // [!code ++]
}

Please leave feedback about this preview feature in our dedicated preview feature feedback issue for views.

Create a view in the underlying database

Currently, you cannot apply views that you define in your Prisma schema to your database with Prisma Migrate or db push. Instead, you must first create the view in the underlying database, either manually or as part of a migration.

For example, take the following Prisma schema with a User model and a related Profile model:

model User {
  id      Int      @id @default(autoincrement())
  email   String   @unique
  name    String?
  profile Profile?
}

model Profile {
  id     Int    @id @default(autoincrement())
  bio    String
  user   User   @relation(fields: [userId], references: [id])
  userId Int    @unique
}

model User {
  id      String   @id @default(auto()) @map("_id") @db.ObjectId
  email   String   @unique
  name    String?
  profile Profile?
}

model Profile {
  id     String @id @default(auto()) @map("_id") @db.ObjectId
  bio    String
  User   User   @relation(fields: [userId], references: [id])
  userId String @unique @db.ObjectId
}

Next, take a UserInfo view in the underlying database that combines the email and name fields from the User model and the bio field from the Profile model.

For a relational database, the SQL statement to create this view is:

CREATE VIEW "UserInfo" AS
    SELECT u.id, email, name, bio
    FROM "User" u
    LEFT JOIN "Profile" p ON u.id = p."userId";

For MongoDB, you can create a view with the following command:

db.createView("UserInfo", "User", [
  {
    $lookup: {
      from: "Profile",
      localField: "_id",
      foreignField: "userId",
      as: "ProfileData",
    },
  },
  {
    $project: {
      _id: 1,
      email: 1,
      name: 1,
      bio: "$ProfileData.bio",
    },
  },
  { $unwind: "$bio" },
]);

Use views with Prisma Migrate and db push

If you apply changes to your Prisma schema with Prisma Migrate or db push, Prisma ORM does not create or run any SQL related to views.

To include views in a migration, run migrate dev --create-only and then manually add the SQL for views to your migration file. Alternatively, you can create views manually in the database.

Add views to your Prisma schema

To add a view to your Prisma schema, use the view keyword.

You can represent the UserInfo view from the example above in your Prisma schema as follows:

view UserInfo {
  id    Int
  email String
  name  String
  bio   String
}

view UserInfo {
  id    String @map("_id") @db.ObjectId
  email String
  name  String
  bio   String
}

Write by hand

A view block is comprised of two main pieces:

• The view block definition
• The view's field definitions

These two pieces allow you to define the name of your view in the generated Prisma Client and the columns present in your view's query results.

Define a view block

To define the UserInfo view from the example above, begin by using the view keyword to define a view block in your schema named UserInfo:

view UserInfo {
  // Fields
}

Define fields

The properties of a view are called fields, which consist of:

• A field name
• A field type

The fields of the UserInfo example view can be defined as follows:

view UserInfo {
  id    Int // [!code highlight]
  email String // [!code highlight]
  name  String // [!code highlight]
  bio   String // [!code highlight]
}

view UserInfo {
  id    String @map("_id") @db.ObjectId // [!code highlight]
  email String // [!code highlight]
  name  String // [!code highlight]
  bio   String // [!code highlight]
}

Each field of a view block represents a column in the query results of the view in the underlying database.

Use introspection

:::warning Currently views can only be introspected with PostgreSQL, MySQL, SQL Server and CockroachDB databases. If you are using another database provider, your views must be added manually. :::

If you have an existing view or views defined in your database, introspection will automatically generate view blocks in your Prisma schema that represent those views.

Assuming the example UserInfo view exists in your underlying database, running the following command will generate a view block in your Prisma schema representing that view:

npx prisma db pull

The resulting view block will be defined as follows:

view UserInfo {
  id    Int?
  email String?
  name  String?
  bio   String?
}

:::warning Please note for now db pull will only introspect views in your schema when using PostgreSQL, MySQL, SQL Server or CockroachDB. Support for this workflow will be extended to other database providers. :::

The views directory

Introspection of a database with one or more existing views will also create a new views directory within your prisma directory (starting with Prisma version 4.12.0). This directory will contain a subdirectory named after your database's schema which contains a .sql file for each view that was introspected in that schema. Each file will be named after an individual view and will contain the query the related view defines.

For example, after introspecting a database with the default public schema using the model used above you will find a prisma/views/public/UserInfo.sql file was created with the following contents:

SELECT
  u.id,
  u.email,
  u.name,
  p.bio
FROM
  (
    "User" u
    LEFT JOIN "Profile" p ON ((u.id = p."userId"))
  );

Query views in Prisma Client

:::note

Be sure to run prisma generate after updating your Prisma schema so that the view definitions become part of your Prisma Client API.

:::

You can query views in Prisma Client in the same way that you query models. For example, the following query finds all users with a name of 'Alice' in the UserInfo view defined above.

const userinfo = await prisma.userInfo.findMany({
  where: {
    name: "Alice",
  },
});

:::note

Write-queries (create/update/delete) are not supported on views.

:::

Special types of views

This section describes how to use Prisma ORM with updatable and materialized views in your database.

Updatable views

Some databases support updatable views (e.g. PostgreSQL, MySQL, and SQL Server). Updatable views allow creating, updating, or deleting entries if the underlying database supports such operations.

Prisma ORM does not allow any mutations (create, update, delete) on views, regardless of the database's capabilities. This change provides guardrails to ensure that views are treated consistently as read-only entities within Prisma Client. As a result, methods to perform writes such as create, update, delete, or upsert are not generated for view blocks in your Prisma Client API.

If you need to modify data represented by a view, you must perform the write operations directly on the underlying tables or use raw SQL queries.

Materialized views

Some databases support materialized views, e.g. PostgreSQL, CockroachDB, MongoDB, and SQL Server (where they're called "indexed views").

Materialized views persist the result of the view query for faster access and only update it on demand.

Currently, Prisma ORM does not support materialized views. However, when you manually create a view, you can also create a materialized view with the corresponding command in the underlying database. You can then use Prisma Client's TypedSQL functionality to execute the command and refresh the view manually.

In the future Prisma Client might support marking individual views as materialized and add a Prisma Client method to refresh the materialized view. Please comment on our views feedback issue with your use case.

Limitations

Prisma ORM treats all view blocks as read-only representations of database queries rather than true tables. Because of this, several limitations apply to ensure Prisma Client remains consistent with the behavior of the underlying database.

No identifiers

Views are virtual tables and do not have inherent primary keys. Hence, you cannot define @id, @@id attributes on a view block.

No indexes

Because views are virtual tables, they cannot have indexes. Therefore, @index and @@index cannot be defined on view blocks.

Unsafe @unique attributes

While Prisma ORM lets you place @unique and @@unique attributes on views, the underlying database and Prisma do not enforce those constraints. Multiple rows can therefore share the same value for a supposedly unique field.

Neither the database nor Prisma ORM enforce the unique constraint expressed by that attribute.

The purpose of the @unique attribute in this case is only to enable relationships across views as well as findUnique queries and cursor-based pagination in Prisma Client.

Disabled write queries

All write operations (create, update, delete, upsert) are disabled and not generated in the Prisma Client.