Getting Started¶
Install¶
- Ensure you have Python 3.6, or above, installed on your system.
- Ensure you have pip for Python (you probably already do).
- Run the following command:
pip install -U preql
Run the interpreter in the console (REPL)¶
To start the interpreter, run the following in your shell:
preql
Preql will use Sqlite’s memory database by default.
To see the running options, type:
preql --help
Explore an existing database¶
When you start the interpreter, you can specify which database to connect to, using a URL.
# Postgresql
preql postgres://user:pass@host/dbname
# MySQL
preql mysql://user:pass@host/dbname
# Sqlite (use existing or create new)
preql sqlite://path/to/file
When already inside the Preql interactive prompt, a Jupyter Notebook, or a running script, use the connect()
method:
connect("sqlite://path/to/file")
Use introspective methods to see a list of the tables, and of the available functions:
// Get a list of all tables in database
>> tables()
// Get help regarding how to use Preql
>> help()
// For example:
>> help(connect)
func connect(uri, load_all_tables, auto_create) = ...
Connect to a new database, specified by the uri
...
Run in a Jupyter Notebook¶
- Install the Preql kernel into jupyter:
preql --install-jupyter
- Run Jupyter Notebook as usual:
jupyter notebook
- create a new notebook with the
Preql
kernel, or open an existing one.
Inside the notebook, use the connect()
function to connect to a database.
For an example, view the following Jupyter notebook: Tutorial: Exploring a database with Preql
Use as a Python library¶
from preql import Preql
p1 = Preql() # Use memory database
p2 = Preql("sqlite://path/to/file") # Use existing or new file
assert p1('sum([1..10])') == 45
Run as a REST / GraphQL server¶
Coming soon!