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Database Storage (DBStorage)

DBStorage stores file bytes directly in the database alongside the File record's data field. This is the default storage backend — no additional infrastructure or packages are needed.

When to Use

  • Prototyping and development
  • Small files (configs, text documents, small images)
  • When you want everything in a single database with no external dependencies

Not recommended for large files or high-traffic scenarios — every file read/write goes through the database.

Configuration

DBStorage has no constructor parameters — it works out of the box:

from amsdal_models.storage.backends.db import DBStorage

storage = DBStorage()

Since it's the default backend, you don't need to configure anything unless you've changed DEFAULT_FILE_STORAGE to something else.

Explicitly setting as default

Via environment variable:

export AMSDAL_DEFAULT_FILE_STORAGE='amsdal_models.storage.backends.db.DBStorage'

Or via code:

from amsdal.storages import set_default_storage
from amsdal_models.storage.backends.db import DBStorage

set_default_storage(DBStorage())

Per-field usage

from amsdal_models.storage.backends.db import DBStorage
from amsdal.models.core.file import File
from amsdal_models.classes.fields.file import FileField
from amsdal_models.classes.model import Model

class MyModel(Model):
    attachment: File = FileField(storage=DBStorage())

How It Works

When a File is saved with DBStorage:

  1. On save — file bytes are read from the source stream and stored in the File model's data field (a binary column in the database).
  2. On open — bytes are read from the data field and returned as an in-memory BytesIO stream.
  3. On delete — the data field is cleared.
  4. URL — returns a placeholder db://<filename> URL (not publicly accessible).

DBStorage sets keeps_local_copy = True, which tells the framework to keep the data field populated and not clear it after persistence.

Async Support

All operations have async counterparts (asave, aopen, adelete, aexists, aurl) that work identically to the sync versions.

Limitations

  • No public URLs — url() returns db://filename, which is not a real URL. If you need publicly accessible file links, use FileSystemStorage or S3Storage.
  • Database size — every file adds its full byte content to the database. Large files will bloat your database.
  • Performance — reading large files goes through the database driver, which is slower than reading from disk or S3.