# Databank
[](https://pypi.org/project/databank) 
Databank is an easy-to-use Python library for making raw SQL queries in a multi-threaded environment.
No ORM, no frills. Only raw SQL queries and parameter binding. Thread-safe. Built on top of [SQLAlchemy](https://www.sqlalchemy.org/).
[](https://www.flickr.com/photos/mratzloff/9169294489/)
(The photo was taken by [Matthew Ratzloff](https://www.flickr.com/photos/mratzloff/) and is licensed under CC BY-NC-ND 2.0.)
## Installation
You can install the latest stable version from [PyPI](https://pypi.org/project/databank/):
```
$ pip install databank
```
**Adapters not included.** Install e.g. `psycopg2` for PostgreSQL:
```
$ pip install psycopg2
```
## Usage
Connect to the database of your choice:
```python
>>> from databank import Database
>>> db = Database("postgresql://user:password@localhost/db", pool_size=2)
```
The keyword arguments are passed directly to SQLAlchemy's `create_engine()` function. Depending on the database you connect to, you have options like the size of connection pools.
> If you are using `databank` in a multi-threaded environment (e.g. in a web application), make sure the pool size is at least the number of worker threads.
Let's create a simple table:
```python
>>> db.execute("CREATE TABLE beatles (id SERIAL PRIMARY KEY, member TEXT NOT NULL);")
```
You can insert multiple rows at once:
```python
>>> params = [
... {"id": 0, "member": "John"},
... {"id": 1, "member": "Paul"},
... {"id": 2, "member": "George"},
... {"id": 3, "member": "Ringo"}
... ]
>>> db.execute_many("INSERT INTO beatles (id, member) VALUES (:id, :member);", params)
```
Fetch a single row:
```python
>>> db.fetch_one("SELECT * FROM beatles;")
{'id': 0, 'member': 'John'}
```
But you can also fetch `n` rows:
```python
>>> db.fetch_many("SELECT * FROM beatles;", n=2)
[{'id': 0, 'member': 'John'}, {'id': 1, 'member': 'Paul'}]
```
Or all rows:
```python
>>> db.fetch_all("SELECT * FROM beatles;")
[{'id': 0, 'member': 'John'},
{'id': 1, 'member': 'Paul'},
{'id': 2, 'member': 'George'},
{'id': 3, 'member': 'Ringo'}]
```
If you are using PostgreSQL with `jsonb` columns, you can use a helper function to serialize the parameter values:
```python
>>> from databank.utils import serialize_params
>>> serialize_params({"member": "Ringo", "song": ["Don't Pass Me By", "Octopus's Garden"]})
{'member': 'Ringo', 'song': '["Don\'t Pass Me By", "Octopus\'s Garden"]'}
```
