Working with scalar lists

Scalar lists are represented by the [] modifier and are only available if the underlying database supports scalar lists. The following example has one scalar String list named pets:

Relational databases
MongoDB
model User {
id Int @id @default(autoincrement())
name String
pets String[]
}

Example field value:

['Fido', 'Snoopy', 'Brian']

Setting the value of a scalar list

The following example demonstrates how to set the value of a scalar list (coinflips) when you create a model:

const createdUser = await prisma.user.create({
data: {
email: 'eloise@prisma.io',
coinflips: [true, true, true, false, true],
},
})

Adding items to a scalar list

In 2.20.0 and later (PostgreSQL only), you can use the atomic push method to add a single value to a scalar list:

const userUpdate = await prisma.user.update({
where: {
id: 9,
},
data: {
coinflips: {
push: true,
},
},
})

In earlier versions, you have to overwrite the entire value. The following example retrieves user, uses push() to add three new coin flips, and overwrites the coinflips field in an update:

const user = await prisma.user.findUnique({
where: {
email: 'eloise@prisma.io',
},
})
if (user) {
console.log(user.coinflips)
user.coinflips.push(true, true, false)
const updatedUser = await prisma.user.update({
where: {
email: 'eloise@prisma.io',
},
data: {
coinflips: user.coinflips,
},
})
console.log(updatedUser.coinflips)
}

Filtering scalar lists

In 2.15.0 and later (Postgres only), you can filter scalar lists - for example, a list of String or Enum types. The following example returns all posts where the tags list includes databases and typescript:

const posts = await prisma.post.findMany({
where: {
tags: {
hasEvery: ['databases', 'typescript'],
},
},
})

NULL values in arrays

Array fields with a NULL value are not considered by following conditions:

  • NOT (array does not contain X)
  • isEmpty (array is empty)

This means that records you might expect to see are not returned. Consider the following examples:

  • The following query returns all posts where the tags do not include databases:

    const posts = await prisma.post.findMany({
    where: {
    NOT: {
    tags: {
    has: 'databases',
    },
    },
    },
    })
    • ✔ Arrays that do not contain "databases", such as {"typescript", "graphql"}
    • ✔ Empty arrays, such as {}

    The query does not return:

    • NULL arrays, even though they do not contain "databases"

The following query returns all posts where tags is empty:

const posts = await prisma.post.findMany({
where: {
tags: {
isEmpty: true,
},
},
})

The query returns:

  • ✔ Empty arrays, such as {}

The query does not return:

  • NULL arrays, even though they could be considered empty

To work around this issue, you can set the default value of array fields to {} at a database level (Prisma schema does not currently support default values for arrays.)

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