# Collection Update

This function allows you to quickly update a record inside the collection with a single button.

### Specifics

| Parameter              | Description                         |
| ---------------------- | ----------------------------------- |
| Display name           | Collection Update                   |
| Usage                  | Used on database collection record. |
| Can use from dashboard | Yes (from inside record's page)     |
| Can use through API    | Yes                                 |

### Configuration

The function requires the following parameters.

| Parameter    | Description                                                |
| ------------ | ---------------------------------------------------------- |
| Collection   | Collection to which to attach this function to.            |
| Display Name | Your custom display name for a function.                   |
| Update Query | MongoDB based update query to use when function is called. |

### Update Query

An update query is a BSON document that is similar to JSON but has some of its own additions. As it is a document, all query needs to be wrapped inside `{ ... }`. The following shows some examples. Full documentation with all available operators and examples can be found in external resources at the end of a page.

#### General update syntax

The following is the general syntax of an update query.

```sql
{
   <operator1>: { <field1>: <value1>, ... },
   <operator2>: { <field2>: <value2>, ... },
   ...
}
```

* **Operator** - a command to execute on its fields.
* **Field** - field name (unique name of a field). To reach nested levels separate fields by `.` and use index  to reach the specific document. An example of a nested field - `details.0.status`.
* **Value** - an updated value of a field.

#### Examples

**$set** - sets the value of a field in a record.

```bash
{ $set: { first_name: 'John', 'details.0.is_active': true } }
```

**$unset** - removes the specified field from a record.

```bash
{ $unset: { quantity: "", instock: "" } }
```

**$inc**- increments the value of the field by the specified amount.

```bash
{ $inc: { quantity: 2, instock: -5 } }
```

### External references

As CodeMash is using the MongoDB database internally, the following resources explain more of how to use an update query.

* [Full update command documentation](https://docs.mongodb.com/manual/reference/method/db.collection.update/)
* [Possible update operators](https://docs.mongodb.com/manual/reference/operator/update/#id1)


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