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Build a Python App

Attention

This page documents an earlier version. Go to the latest (v2.3) version.

Install the psycopg2 driver

Install the python PostgreSQL driver using the following command. You can get further details for the driver here.

$ pip install psycopg2-binary

Working Example

Prerequisites

This tutorial assumes that you have:

installed YugabyteDB and created a universe with YSQL enabled. If not, please follow these steps in the Quick Start guide.

Writing the python code

Create a file yb-sql-helloworld.py and add the following content to it.

import psycopg2

# Create the database connection.                                                                 
conn = psycopg2.connect("host=127.0.0.1 port=5433 dbname=postgres user=postgres password=postgres")

# 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 pre-exist.)
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()

Running the application

To run the application, type the following:

$ python yb-sql-helloworld.py

You should see the following output.

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