# addons.Preview

## Model Info

| Key | Value |
|---|-----|
| Model Name | Preview |
| Verbose Name | preview |
| Verbose Name Plural | previews |
| Docstring | <p>Preview(created, modified, id, addon, caption, position, sizes)</p> |
| Is Abstract | False |
| Is Proxy | False |
| Is Managed | True |
| Ordering | ('position', 'created') |
| Permissions | [] |
| Default Permissions | ('add', 'change', 'delete', 'view') |
| Indexes | [<Index: fields=['addon'] name='previews_addon_idx'>, <Index: fields=['addon', 'position', 'created'] name='addon_position_created_idx'>] |
| Constraints | [] |
| Database Table | previews |
| Base Manager | None |
| Default Manager | None |
| File | /data/olympia/src/olympia/addons/models.py |
| Starting Line Number | 2429 |
| Method Resolution Order | (<class 'olympia.addons.models.Preview'>, <class 'olympia.amo.models.BasePreview'>, <class 'olympia.amo.models.ModelBase'>, <class 'olympia.amo.models.SaveUpdateMixin'>, <class 'django.db.models.base.Model'>, <class 'django.db.models.utils.AltersData'>, <class 'object'>) |

## Fields

| Field Name | Field Type | Database Column | Database Type | Verbose Name |
|----------|----------|---------------|-------------|------------|
| `addon` | ForeignKey | addon_id | integer UNSIGNED | addon |
| `caption` | TranslatedField | caption | integer UNSIGNED | caption |
| `created` | DateTimeField | created | datetime(6) | created |
| `deletedpreviewfile` | ManyToOneRel |  | integer UNSIGNED |  |
| `id (pk)` | PositiveAutoField | id | integer UNSIGNED AUTO_INCREMENT | id |
| `modified` | DateTimeField | modified | datetime(6) | modified |
| `position` | IntegerField | position | integer | position |
| `sizes` | JSONField | sizes | json | sizes |

## Relations

| Field Name | Field Type | Database Column | Database Type | Related Model | Related Name |
|----------|----------|---------------|-------------|-------------|------------|
| `addon` | ForeignKey | addon_id | integer UNSIGNED | addons.Addon | previews |
| `caption` | TranslatedField | caption | integer UNSIGNED | translations.Translation | Preview_caption_set+ |

fields_reverse_relation=[FieldReverseRelation(name='preview_set', field_type='ManyToOneRel', field_db_type='integer UNSIGNED', related_model='addons.DeletedPreviewFile', field_name_on_related_model='preview', field_type_on_related_model='ForeignKey')]

## Reverse Relations

| Field Name | Field Type | Database Type | Related Model | Field Name on Related Model | Field Type on Related Model |
|----------|----------|-------------|-------------|---------------------------|---------------------------|
| `preview_set` | ManyToOneRel | integer UNSIGNED | addons.DeletedPreviewFile | preview | ForeignKey |

## Methods

### Other Methods

| Method Name | Signature |
|-----------|---------|
| `delete_preview_files` | `(sender, instance, **kw)` |
| `get_admin_absolute_url` | `(self)` |
| `get_admin_url_path` | `(self)` |
| `get_format` | `(self, for_size)` |
| `get_next_by_created` | `(self, *, field=<django.db.models.fields.DateTimeField: created>, is_next=True, **kwargs)` |
| `get_next_by_modified` | `(self, *, field=<django.db.models.fields.DateTimeField: modified>, is_next=True, **kwargs)` |
| `get_previous_by_created` | `(self, *, field=<django.db.models.fields.DateTimeField: created>, is_next=False, **kwargs)` |
| `get_previous_by_modified` | `(self, *, field=<django.db.models.fields.DateTimeField: modified>, is_next=False, **kwargs)` |
| `get_unfiltered_manager` | `()` |
| `reload` | `(self)` |
| `serializable_reference` | `(self)` |
| `update` | `(self, **kw)` |


### Private Methods

| Method Name | Signature |
|-----------|---------|
| `_get_field_value_map` | `(self, meta, exclude=None)` |
| `_image_path` | `(self, folder, file_ext)` |
| `_image_url` | `(self, folder, file_ext)` |


## Custom Managers

### default

**Class:** `ManagerBase`

*Base for all managers in AMO.

Returns BaseQuerySets.

If a model has translated fields, they'll be attached through a transform
function.*

#### Custom Methods

##### `transform(self, fn)`


#### Custom QuerySet

**Class:** `BaseQuerySet`

*Represent a lazy database lookup for a set of objects.*

##### Custom Methods

###### `no_transforms(self)`

###### `only_translations(self)`

*Remove all transforms except translations.*

###### `optimized_count(self)`

*Slightly optimized count() for cases where there is a DISTINCT in the
queryset.

When a count() call is made on a queryset that has a distinct, that
causes django to run the full SELECT (including all fields, distinct,
ordering etc) in a subquery and then COUNT() on the result of that
subquery, which is costly/innefficient. That's tracked in
https://code.djangoproject.com/ticket/30685.
We can't easily fix the fact that there is a subquery, but we can
avoid selecting all fields and ordering in that subquery needlessly.*

###### `pop_transforms(self)`

###### `transform(self, fn)`

### objects

**Class:** `ManagerBase`

*Base for all managers in AMO.

Returns BaseQuerySets.

If a model has translated fields, they'll be attached through a transform
function.*

#### Custom Methods

##### `transform(self, fn)`


#### Custom QuerySet

**Class:** `BaseQuerySet`

*Represent a lazy database lookup for a set of objects.*

##### Custom Methods

###### `no_transforms(self)`

###### `only_translations(self)`

*Remove all transforms except translations.*

###### `optimized_count(self)`

*Slightly optimized count() for cases where there is a DISTINCT in the
queryset.

When a count() call is made on a queryset that has a distinct, that
causes django to run the full SELECT (including all fields, distinct,
ordering etc) in a subquery and then COUNT() on the result of that
subquery, which is costly/innefficient. That's tracked in
https://code.djangoproject.com/ticket/30685.
We can't easily fix the fact that there is a subquery, but we can
avoid selecting all fields and ordering in that subquery needlessly.*

###### `pop_transforms(self)`

###### `transform(self, fn)`


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