Correct storage backend documentation

README.md

@@ -33,13 +33,40 @@ This
 is a pure python distribution and - thus - should require no external
 compilers or tools besides those contained within Python itself.
 
-# Notes for this fork
+# Project notes
 
-- **Default storage:** this fork uses Parquet v2 files by default (via `pyarrow`) for improved I/O performance and reliability. If `pyarrow` is not available, it falls back to TinyDB's default JSON storage.
+- **Default storage:** TinyMongo uses TinyDB's default JSON storage unless another backend is selected.
+- **Optional storage backends:** Parquet v2, SQLite, and DuckDB backends are available.
 - **Concurrency:** writes use atomic temp-file replace and optional advisory locks (`portalocker`) to reduce corruption risk under concurrent writers.
 - **Tests & CI:** a GitHub Actions workflow is included at `.github/workflows/ci.yml` to run unit tests and linters across Python versions. See `requirements-dev.txt` for dev dependencies.
 
 
+# Backend options
+
+TinyMongo defaults to TinyDB's JSON storage:
+
+```python
+    from tinymongo import TinyMongoClient
+
+    connection = TinyMongoClient("/path/to/folder")
+```
+
+You can select another backend with the `backend` argument:
+
+```python
+    parquet_connection = TinyMongoClient("/path/to/folder", backend="parquet")
+    sqlite_connection = TinyMongoClient("/path/to/folder", backend="sqlite")
+    duckdb_connection = TinyMongoClient("/path/to/folder", backend="duckdb")
+```
+
+Available backends:
+
+- `tinydb` or `json`: TinyDB's default JSON storage. This is the default and writes `.json` files.
+- `parquet` or `parquetv2`: Parquet v2 storage backed by `pyarrow`. This writes `.parquet` files.
+- `sqlite`: SQLite storage using Python's standard `sqlite3` module. This writes `.sqlite` files.
+- `duckdb`: DuckDB storage. Install `duckdb` before using this backend. This writes `.duckdb` files.
+
+
 # Examples
 
 The quick start is shown below.  For a more detailed look at tinymongo,

docs/MIGRATION.md

@@ -5,7 +5,8 @@ This guide helps you migrate from earlier `tinymongo` versions to `1.0.0`.
 ## Key changes
 
 - The package now uses `pyproject.toml` for packaging metadata.
-- Default storage is now Parquet v2 (`pyarrow`) instead of TinyDB JSON files.
+- Default storage remains TinyDB JSON storage.
+- Parquet v2, SQLite, and DuckDB are available as optional storage backends.
 - Concurrent writes are safer due to atomic file replace and optional file locks.
 - Optional `uv` extras are available for dependency-managed ASGI usage.
 
@@ -24,6 +25,7 @@ pip install .[uv]
 
 ## Notes
 
-- The default storage uses Parquet and requires `pyarrow`.
-- If `pyarrow` is not installed, `tinymongo` falls back to TinyDB JSON storage.
+- The default storage uses TinyDB JSON storage.
+- Parquet storage requires `pyarrow`; DuckDB storage requires `duckdb`.
+- Select optional storage backends with `TinyMongoClient(path, backend="parquet")`, `backend="sqlite"`, or `backend="duckdb"`.
 - For local development, install `requirements-dev.txt` and run `pytest -q`.