# AIO-Databases
The package gives you async support for a range of databases (SQLite,
PostgreSQL, MySQL).
[](https://github.com/klen/aio-databases/actions)
[](https://pypi.org/project/aio-databases/)
[](https://pypi.org/project/aio-databases/)
## Features
* Has no dependencies (except databases drivers)
* Supports [asyncio](https://docs.python.org/3/library/asyncio.html) and [trio](https://github.com/python-trio/trio)
* Supports [aiosqlite](https://github.com/omnilib/aiosqlite),
[aiomysql](https://github.com/aio-libs/aiomysql),
[aiopg](https://github.com/aio-libs/aiopg),
[asyncpg](https://github.com/MagicStack/asyncpg),
[triopg](https://github.com/python-trio/triopg),
[trio_mysql](https://github.com/python-trio/trio-mysql)
* Manage pools of connections
* Manage transactions
## Requirements
* python >= 3.7
## Installation
**aio-databases** should be installed using pip:
```shell
$ pip install aio-databases
```
You have to choose and install the required database drivers with:
```shell
# To support SQLite
$ pip install aio-databases[aiosqlite] # asyncio
# To support MySQL
$ pip install aio-databases[aiomysql] # asyncio
$ pip install aio-databases[trio_mysql] # trio
# To support PostgreSQL (choose one)
$ pip install aio-databases[aiopg] # asyncio
$ pip install aio-databases[asyncpg] # asyncio
$ pip install aio-databases[triopg] # trio
# To support ODBC (alpha state)
$ pip install aio-databases[aioodbc] # asyncio
```
## Usage
### Init a database
```python
from aio_databases import Database
# Initialize a database
db = Database('sqlite:///:memory:') # with default driver
# Flesh out the driver
db = Database('aiosqlite:///:memory:', **driver_params)
```
### Setup a pool of connections (optional)
Setup a pool of connections
```python
# Initialize a database's pool
async def my_app_starts():
await db.connect()
# Close the pool
async def my_app_ends():
await db.disconnect()
# As an alternative users are able to use the database
# as an async context manager
async with db:
await my_main_coroutine()
```
### Get a connection
```python
# Acquire and release (on exit) a connection
async with db.connection():
await my_code()
# Acquire a connection only if it not exist
async with db.connection(False):
await my_code()
```
If a pool is setup it will be used
### Run SQL queries
```python
await db.execute('select $1', '1')
await db.executemany('select $1', '1', '2', '3')
records = await db.fetchall('select (2 * $1) res', 2)
assert records == [(4,)]
record = await db.fetchone('select (2 * $1) res', 2)
assert record == (4,)
assert record['res'] == 4
result = await db.fetchval('select 2 * $1', 2)
assert result == 4
```
* Iterate through rows one by one
```python
async for rec in db.iterate('select name from users'):
print(rec)
```
### Manage connections
By default the database opens and closes a connection for a query.
```python
# Connection will be acquired and released for the query
await db.fetchone('select %s', 42)
# Connection will be acquired and released again
await db.fetchone('select %s', 77)
```
Manually open and close a connection
```python
# Acquire a new connection object
async with db.connection():
# Only one connection will be used
await db.fetchone('select %s', 42)
await db.fetchone('select %s', 77)
# ...
# Acquire a new connection or use an existing
async with db.connection(False):
# ...
```
If there any connection already `db.method` would be using the current one
```python
async with db.connection(): # connection would be acquired here
await db.fetchone('select %s', 42) # the connection is used
await db.fetchone('select %s', 77) # the connection is used
# the connection released there
```
### Manage transactions
```python
# Start a tranction using the current connection
async with db.transaction() as trans1:
# do some work ...
async with db.transaction() as trans2:
# do some work ...
await trans2.rollback()
# unnessesary, the transaction will be commited on exit from the
# current context
await trans1.commit()
# Create a new connection and start a transaction
async with db.tranction(True) as trans:
# do some work ...
```
## Bug tracker
If you have any suggestions, bug reports or annoyances please report them to
the issue tracker at https://github.com/klen/aio-databases/issues
## Contributing
Development of the project happens at: https://github.com/klen/aio-databases
## License
Licensed under a [MIT License](http://opensource.org/licenses/MIT)