# Binary

Binary fields store, as the name implies, raw binary data. This is the rough equivalent to a BLOB field in relational databases. The amount of storage space [**is limited**](https://docs.mongodb.com/manual/reference/limits/#bson-documents) to 16MB per document. For storage of binray data beyond this limit please utilize [GridFS](https://docs.mongodb.com/manual/core/gridfs/index.html) support.

### Import

`from marrow.mongo.field import Binary`

### Inherits

`marrow.mongo:`**`Field`**

## Attributes

This field type inherits all [`Field` attributes](https://github.com/marrow/mongo/tree/128b1ec81ec6a48e05a95c32b636deede377854b/reference/field/field.md#attributes) and represents a singular, scalar binary string value. It has no specific configuration options.

## Usage

Instantiate and assign an instance of this class during construction of a new `Document` subclass. Accessing as a class attribute will return a Queryable allowing binary string filtering operations, and access as an instance attribute will return a `bytes` cast value.

## Example

Users may wish to utilize a "profile image" to identify themselves. Utilizing a Binary field (and appropriate upload limits) can facilitate this. When presenting back via HTTP, the mime type would be useful to track; see GridFS for this capability as well.

```python
class User(Document):
    name = String('_id')
    avatar = Binary()

me = User("amcgregor")

with open('avatar.png', 'rb') as fh:
    me.avatar = fh.read()

me.insert_one()
```

## See Also

* [`String`](/reference/fields/string.md)


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