Prisma ClientBasic Data Access

Reading Data (JavaScript)

Overview

The Prisma client is based on the operations defined in the GraphQL schema of your Prisma API. For reading data, it basically mirrors the GraphQL queries of your Prisma service.

For this page, we'll assume your Prisma API is based on the following datamodel:

type Link {
  id: ID! @unique
  createdAt: DateTime!
  description: String!
  url: String!
  postedBy: User
  votes: [Vote!]!
}

type User {
  id: ID! @unique
  name: String!
  email: String! @unique
  password: String!
  links: [Link!]!
  votes: [Vote!]!
}

type Vote {
  id: ID! @unique
  link: Link!
  user: User!
}
  • You can view what the generated GraphQL schema for the API here
  • You can view what the generated JavaScript client here.

Whenever a model is queried using the Prisma client, all scalar fields of that model are fetched. This is true no matter if a single object or a list of objects is queried.

For example, the following query returns all scalar fields of a single User:

const user = await prisma.user({ email: "bob@prisma.io" })

In this case, the returned user object will have four properties (that correspond to the scalar fields of the User model): id, name, email and password.

The links and votes fields are both relation fields and are therefore not included in the query.

Here is an example of fetching a list of User objects:

const users = await prisma.users()

Similar to the previous query, each object inside the users array only has the scalar and no relation fields.

Fetching single objects

For each model type in your datamodel, there is a method generated in the Prisma client API that allows to fetch single objects of that model. The method is named after the type but starts with a lowercase character. For the sample datamodel from above, the three methods for fetching single User, Link and Vote objects are called user, link and vote.

The input for these functions is an object that has as properties any unique field of the model. This means, for all three methods, the id field is accepted (as the corresponding models each have an id field annotated as @unique). The input object for the user method additionaly has an email field.

  • View the type of where for Link here
  • View the type of where for User here
  • View the type of where for Vote here

Examples

Fetch a single vote by its id:

JavaScript
GraphQL
const vote = await prisma.vote({ id: "cjlgpyueg001o0a239d3i07ao" })
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Fetch a single user by their email:

JavaScript
GraphQL
const user = await prisma.user({ email: "alice@prisma.io" })
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Fetching lists

For each model type in your datamodel, there is a method generated in the Prisma client API that allows to fetch a list of those model objects. The method is named after the model but starts with a lowercase character and uses the plural form. For the sample datamodel from above, the three methods for fetching lists of User, Link and Vote models are called users, links and votes.

The input arugment for these functions is an object that has properties for:

Examples

Fetch all links:

JavaScript
GraphQL
const links = await prisma.links()
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Fetch a list of users:

JavaScript
GraphQL
const users = await prisma.users()
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Relations

Prisma client has a fluent API to query relations in your data graph. Meaning you can simply chain your method calls to navigate the relation properties of the returned models.

This is only possible when retrieving single objects, not for lists. Meaning you can not query relation fields of objects that are returned in a list, e.g.:

// not possible
const result = await prisma
  .users()
  .links()

In this example, users() already returns a list, so it's not possible to query the links relation of each user object inside the list.

Examples

Query all the links of a single user:

JavaScript
GraphQL
const linksByUser = await prisma
  .user({ email: "alice@prisma.io" })
  .links()
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Query all the votes made by a certain user:

JavaScript
GraphQL
const votesByUser = await prisma
 .user({ email: "alice@prisma.io" })
 .votes()
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Using fragments for fine-grained data access

Instead of querying all scalar fields of a model (which is the default behavior), you can specify which fields you'd like retrieve by using the $fragment API feature (based on GraphQL). This is useful to exclude large unneeded fields (like BLOB values or huge strings) or to even retrieve relations.

Examples

Fetch the name and email of the users as well the the description and url of their related links:

JavaScript
GraphQL
const fragment = `
fragment UserWithLinks on User {
  name
  email
  links {
    description
    url
  }
}
`

const userWithPosts = await prisma.users().$fragment(fragment)
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Basic filters for lists

Basic filters let you specify certain criteria to constrain which objects should be returned in a list. The filters are specified in the where object of the input argument which is accepted by any list query.

The type of the where object depends on the model for which it was generated.

  • View the type of where for Link here
  • View the type of where for User here
  • View the type of where for Vote here

It is also possible to combine multiple filters using the AND and OR fields.

Examples

Fetch users that have an A in their names:

JavaScript
GraphQL
const usersWithAInName = await prisma
  .users({
    where: {
      name_contains: "A"
    }
  })
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Fetch users called Alice or Bob:

JavaScript
GraphQL
const usersCalledAliceOrBob = await prisma
  .users({
    where: {
      name_in: ["Alice", "Bob"]
    }
  })
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Fetch links created before December 24, 2018:

JavaScript
GraphQL
const linksBeforeChristmas = await prisma
  .links({
    where: {
      createdAt_lt: "2018-12-24" 
    }
  })
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Dates and times in the Prisma client API follow the ISO 8601 standard which generally is of the form: YYYY-MM-DDThh:mm:ss. Learn more.

Fetch links that have prisma or graphql in their description and were created in 2018:

JavaScript
GraphQL
const filteredLinks = await prisma
  .links({
    where: {
      AND: [
        {
          OR: [{
            description_contains: "graphql",
          }, {
            description_contains: "prisma",
          }]
        }, 
        {
          AND: [{
            createdAt_gt: "2017"
          }, {
            createdAt_lt: "2019"
          }]
        }
      ],
    }
  })
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The AND filter can actually be omitted since multiple filter criteria are by default combined using a logical and. This means the above filter can also be expressed as follows:

JavaScript
GraphQL
const filteredLinks = await prisma
  .links({
    where: {
      OR: [{
        description_contains: "graphql"
      }, {
        description_contains: "prisma"
      }],
      createdAt_gt: "2017",
      createdAt_lt: "2019"
    }
  })
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Relational filters for lists

Relational filters can be used to constrain the returned objects on a relation list field. The types used for filtering are identical to basic filters, the only difference is that the filters are not applied on the first level of the method call but when querying a relation on the second level.

Examples

JavaScript
GraphQL
const linksByUserBeforeChristmas = await prisma
  .user({ email: "alice@prisma.io" })
  .links({
    where: {
      createdAt_lt: "2017-12-24" 
    }
  })
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Ordering

When querying a list of model objects, you can order (sort) the list by any scalar field of that model type. Each generated method to query a list of models therefore accepts the orderBy field on its input object.

The type of the orderBy field depends on the scalar fields of the model for which it was generated.

  • View the type of orderBy for Link here
  • View the type of orderBy for User here
  • View the type of orderBy for Vote here

Examples

Sort links by their creation date (ascending):

JavaScript
GraphQL
const sortedLinks = prisma
  .links({
    orderBy: "createdAt_ASC"
  })
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Sort users alphabetically by their names (descending):

JavaScript
GraphQL
const sortedUsers = prisma
  .users({
    orderBy: "name_DESC"
  })
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Aggregations

You can submit aggregation queries via connection queries. The following aggregation functions are supported:

  • count: Counts the number of objects in a list
  • avg (coming soon): Computes the average of a list of numbers.
  • median (coming soon): Computes the median of a list of numbers.
  • max (coming soon): Returns the greatest element of a list of numbers.
  • min (coming soon): Returns the smallest element of a list of numbers.
  • sum (coming soon): Computes the sum of a list of numbers.

See this GitHub issue to learn more about the upcoming aggregation functions.

Examples

Count the number of link objects:

JavaScript
GraphQL
const linkCount = await prisma
  .linksConnection()
  .aggregate()
  .count()
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