# Working with scalar lists (Prisma ORM v6) (/docs/orm/v6/prisma-client/special-fields-and-types/working-with-scalar-lists-arrays)

How to read, write, and filter by scalar lists / arrays.

Location: ORM > v6 > Prisma Client > Special Fields and Types > Working with scalar lists

[Scalar lists](/guides/reference-6-v6-reference-prisma-schema-reference#-modifier) 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

```prisma highlight=4;normal 
model User {
  id   Int      @id @default(autoincrement())
  name String
  pets String[] // [!code highlight]
}
```

#### MongoDB

```prisma highlight=4;normal 
model User {
  id   String   @id @default(auto()) @map("_id") @db.ObjectId
  name String
  pets String[] // [!code highlight]
}
```

Example field value:

```json5
["Fido", "Snoopy", "Brian"]
```

## Setting the value of a scalar list

The following example demonstrates how to [`set`](/guides/reference-6-v6-reference-prisma-client-reference#set-1) the value of a scalar list (`coinflips`) when you create a model:

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

## Unsetting the value of a scalar list

> \[!WARNING]
> This method is available on MongoDB only in versions
> [3.11.1](https://github.com/prisma/orm/releases/tag/3.11.1) and later.

The following example demonstrates how to [`unset`](/guides/reference-6-v6-reference-prisma-client-reference#unset) the value of a scalar list (`coinflips`):

```ts
const createdUser = await prisma.user.create({
  data: {
    email: "eloise@prisma.io",
    coinflips: {
      unset: true,
    },
  },
});
```

Unlike `set: null`, `unset` removes the list entirely.

## Adding items to a scalar list

> \[!WARNING]
> Available for:
>
> - PostgreSQL in versions [2.15.0](https://github.com/prisma/orm/releases/tag/2.15.0) and later
> - CockroachDB in versions [3.9.0](https://github.com/prisma/orm/releases/tag/3.9.0) and later
> - MongoDB in versions [3.11.0](https://github.com/prisma/orm/releases/tag/3.11.0) and later

Use the [`push`](/guides/reference-6-v6-reference-prisma-client-reference#push) method to add a single value to a scalar list:

```ts
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`:

```ts
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

> \[!WARNING]
> Available for:
>
> - PostgreSQL in versions [2.15.0](https://github.com/prisma/orm/releases/tag/2.15.0) and later
> - CockroachDB in versions [3.9.0](https://github.com/prisma/orm/releases/tag/3.9.0) and later
> - MongoDB in versions [3.11.0](https://github.com/prisma/orm/releases/tag/3.11.0) and later

Use [scalar list filters](/guides/reference-6-v6-reference-prisma-client-reference#scalar-list-filters) to filter for records with scalar lists that match a specific condition. The following example returns all posts where the tags list includes `databases` _and_ `typescript`:

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

### `NULL` values in arrays

> \[!WARNING]
> This section applies to:
>
> - PostgreSQL in versions [2.15.0](https://github.com/prisma/orm/releases/tag/2.15.0) and later
> - CockroachDB in versions [3.9.0](https://github.com/prisma/orm/releases/tag/3.9.0) and later

When using scalar list filters with a relational database connector, array fields with a `NULL` value are not considered by the 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`:

  ```ts
  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:

```ts
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 `[]`.

## Related pages

- [`Composite types`](/guides/prisma-client-v6-special-fields-and-types-composite-types): Learn about composite types in Prisma Client for MongoDB
- [`Null and undefined`](/guides/prisma-client-v6-special-fields-and-types-null-and-undefined): How Prisma Client handles null and undefined
- [`Working with compound IDs and unique constraints`](/guides/prisma-client-v6-special-fields-and-types-working-with-composite-ids-and-constraints): How to read, write, and filter by compound IDs and unique constraints.
- [`Working with Json fields`](/guides/prisma-client-v6-special-fields-and-types-working-with-json-fields): How to read, write, and filter by Json fields.

## Related pages

- [Authentication & Tools](./authentication-tools-index.md)
- [Build](./build-index.md)
- [Changelog](../changelog.md)
- [Concepts](./concepts-index.md)
- [Console commands](./console-commands-index.md)
- [Contract Authoring](./contract-authoring-index.md)
- [Core Concepts](./core-concepts-index.md)
- [Data Modeling](./data-modeling-index.md)
- [Database](./database-index.md)
- [DB commands](./db-commands-index.md)

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