# Mutations

A GraphQL mutation is used for modifying data. Separate mutations are available for `create`, `update`, and `delete` and these can be individually enabled per object class. In addition, the mutation `persist` is enabled (allowing batch create) whenever the object class has `create` enabled for GraphQL. Read more about enabling GraphQL settings [here](https://docs.appfarm.io/reference/data-model/graphql/..#enable-graphql). Mutations can return the modified object(s), so you can immediately access the updated object without having to make a separate request.

{% hint style="info" %}
**Good to know**

Mutations can be built by using the [GraphiQL Explorer](https://docs.appfarm.io/reference/data-model/graphql/..#graphiql-explorer). Simply select what to mutate, and the IDE will handle the syntax!
{% endhint %}

## Create

Create a single object in the database. The built-in Created Date property (and Created By, if enabled) is automatically set server-side.

```graphql
// Create a new project and return the ID
mutation {
    createproject(title:"Analyze office layout", projectNumber:1124) {
  _id
}}
```

## Persist (create many / batch create)

For GraphQL enabled Object Classes with `Enable Create` , you may create multiple objects at once though the `persist` endpoint.

For example, an Object Class `Car` with GraphQL Endpoint Name `car` will have the mutation persistCar available. See example usage below.

```graphql
// Creating 3 cars with persistCar
// Note that default values defined on the Object Class Properties will be used, 
// and the _id will be auto generated, unless any of these are overridden below
mutation{
	persistCar(
		objects: [
			{
				brand: "Skoda",
				model: "Enyaq"
            		},
			{
				brand: "Honda",
				model: "Civic"
            		},
			{
				brand: "Ferrari",
				model: "F40"
            		}
		]
    )
}
```

Note that you may also override the default \_id in the above `persistCar` mutation, simply by adding a valid (and unique) objectid to each record:

```graphql
			{
				_id: "5b71631743501ec10595a144",
				brand: "Skoda",
				model: "Enyaq"
           		}
```

## Update

Update one or more objects in the database. The built-in Updated Date property (and Updated By, if enabled) is automatically set server-side.

The first parameter is a filter object used to determine which object to update. Find more about filters under Queries.

The second parameter is an input object containing the properties you wish to update.

A count of the number of updated objects is returned.

{% code overflow="wrap" %}

```graphql
// For the project with the ID "5ef212569decde19f8650de8", update the title to "Reconfigure office layout"
mutation {
    updateproject(
        filter: {
            _id: { eq: "5ef212569decde19f8650de8" }
        },
        input: {
		        title: "Reconfigure office layout"
        }
    ) {
      updatedCount
    }
}

// For any task in the project "619cbc23b9db097574d42c8c", set complete to true
mutation {
  updatetask(
    filter: {
      project: {eq: "619cbc23b9db097574d42c8c"}
    },
    input: {
      complete: true
    }
  ) {
    updatedCount
  }
}
```

{% endcode %}

## Delete

Permanently delete one or more objects. A count of the number of updated objects is returned.

```graphql
// Delete the project with the id "61813d19839f82002b44f8a0"
mutation {
    deleteproject(filter: {_id: {eq: "61813d19839f82002b44f8a0"}}) {
      deletedCount
    }
}

// Delete all projects that are completed
mutation {
    deleteproject(filter: {complete: {eq: true}}) {
      deletedCount
    }
}
```

## Generate Random Identifiers

Generate random identifiers for objects created prior to enabling [Random identifier](https://docs.appfarm.io/reference/object-classes#meta-data) on an Object Class in the [Global data model](https://docs.appfarm.io/reference/data-model). This operation is performed in batches.

{% hint style="info" %}
For this mutation to work, [GraphQL needs to be enabled](https://docs.appfarm.io/reference/data-model/graphql/..#enable-graphql), and the Update operation selected. In addition, the Enable GraphQL Auxiliary Endpoints setting you find under Environment needs to be switched on.
{% endhint %}

The first parameter references the node name of the built-in property random identifier.

The second parameter determines how large the batches will be. The maximum number is 1000.

Both parameters are required.

<pre class="language-graphql"><code class="lang-graphql">// Generate random identifiers for existing projects that don't have it
mutation {
    populateBuiltinPropertyProject(propertyId: af_randomId, maxUpdates: 2) {
        updatedCount
    }
<strong>}
</strong></code></pre>