Python drivers

• YugabyteDB Psycopg2
• PostgreSQL Psycopg2

Psycopg is the most popular PostgreSQL database adapter for Python. Its main features are the complete implementation of the Python DB API 2.0 specification and the thread safety (several threads can share the same connection). YugabyteDB has full support for Psycopg2.

CRUD operations with PostgreSQL Psycopg2 driver

Learn how to establish a connection to YugabyteDB database and begin basic CRUD operations using the steps in the Build an application page under the Quick start section.

The following sections break down the quick start example to demonstrate how to perform common tasks required for Python application development using the PostgreSQL Psycopg2 driver.

After completing these steps, you should have a working Python application that uses Psycopg2 to connect to your cluster, set up tables, run queries, and print out results.

Step 1: Download the driver dependency

Building Psycopg requires a few prerequisites (a C compiler, some development packages). Refer to Installation and the FAQ in the Psycopg documentation.

If prerequisites are met, you can install psycopg like any other Python package, using pip to download it from PyPI:

$ pip install psycopg2

or using setup.py if you have downloaded the source package locally:

$ python setup.py build
$ sudo python setup.py install

You can also obtain a stand-alone package, not requiring a compiler or external libraries, by installing the psycopg2-binary package from PyPI:

$ pip install psycopg2-binary

The binary package is a practical choice for development and testing but in production it is advised to use the package built from sources.

Step 2: Connect to your cluster

Python applications can connect to and query the YugabyteDB database. First, import the psycopg2 package.

import psycopg2

The Connection details can be provided as a string or a dictionary.

• Connection String

  "dbname=database_name host=hostname port=port user=username  password=password"
  

• Connection Dictionary

  user = 'username', password='xxx', host = 'hostname', port = 'port', dbname = 'database_name'
  

Example URL for connecting to YugabyteDB can be seen below.

conn = psycopg2.connect(dbname='yugabyte',host='localhost',port='5433',user='yugabyte',password='yugabyte')

Example URL for connecting to YugabyteDB cluster enabled with on the wire SSL encryption:

conn = psycopg2.connect("host=<hostname> port=5433 dbname=yugabyte user=<username> password=<password> sslmode=verify-full sslrootcert=/Users/my-user/Downloads/root.crt")

Use SSL

If you have created a cluster on YugabyteDB Managed, follow the steps to obtain the cluster connection parameters and SSL Root certificate.

Step 3: Query the YugabyteDB cluster from your application

1. Create a new Python file called QuickStartApp.py in the base package directory of your project.

2. Copy the following sample code to set up tables and query the table contents. Replace the connection string yburl with the cluster credentials and SSL certificate, if required.

import psycopg2

# Create the database connection.

yburl = "host=127.0.0.1 port=5433 dbname=yugabyte user=yugabyte password=yugabyte"

conn = psycopg2.connect(yburl)

# Open a cursor to perform database operations.
# The default mode for psycopg2 is "autocommit=false".

conn.set_session(autocommit=True)
cur = conn.cursor()

# Create the table. (It might preexist.)

cur.execute(
  """
  DROP TABLE IF EXISTS employee
  """)

cur.execute(
  """
  CREATE TABLE employee (id int PRIMARY KEY,
                         name varchar,
                         age int,
                         language varchar)
  """)
print("Created table employee")
cur.close()

# Take advantage of ordinary, transactional behavior for DMLs.

conn.set_session(autocommit=False)
cur = conn.cursor()

# Insert a row.

cur.execute("INSERT INTO employee (id, name, age, language) VALUES (%s, %s, %s, %s)",
            (1, 'John', 35, 'Python'))
print("Inserted (id, name, age, language) = (1, 'John', 35, 'Python')")

# Query the row.

cur.execute("SELECT name, age, language FROM employee WHERE id = 1")
row = cur.fetchone()
print("Query returned: %s, %s, %s" % (row[0], row[1], row[2]))

# Commit and close down.

conn.commit()
cur.close()
conn.close()

When you run the QuickStartApp.py project, you should see output similar to the following:

Created table employee
Inserted (id, name, age, language) = (1, 'John', 35, 'Python')
Query returned: John, 35, Python

If there is no output or you get an error, verify the parameters included in the connection string.

Next steps

• Learn how to build Python applications using Django
• Learn how to build Python applications using SQLAlchemy
• Learn more about fundamentals of the PostgreSQL psycopg2 Driver