The psycopg2 module can be used to connect to a Postgres database. pip install can be used to install the wheel and psycopg2-binary packages.

pip install wheel
pip install psycopg2-binary

And here is an example of how to connect to Postgres database. This is just a super simple example, with no error handling.

#!/usr/bin/python3
import psycopg2

db_name = "mydb"
db_host = "10.11.12.13"
db_user = "john.doe"
db_pass = "itsasecret"
db_port = "5432"

connection = psycopg2.connect(database=db_name,
                        host=db_host,
                        user=db_user,
                        password=db_pass,
                        port=db_port)

connection.close()

And here is an example that includes try / except / else / finally for error handling and timeout.

#!/usr/bin/python3
import psycopg2
import sys

db_name = "mydb"
db_host = "10.11.12.13"
db_user = "john.doe"
db_pass = "itsasecret"
db_port = "5432"

try:
  connection = psycopg2.connect(database=db_name,
                        host=db_host,
                        user=db_user,
                        password=db_pass,
                        port=db_port,
                        timeout=3)
except Exception as exception:
  print(f"got the following exception when attempting to connect to Postgres database {db_host}:{db_port}/{db_name} as {db_user}: {exception}")
  sys.exit()
else:
  print(f"Successfully connected to Postgres Database {db_host}:{db_port}/{db_name} as {db_user}")
  try:
    connection.close()
  except Exception as exception:
    print(f"got the following exception when attempting connection.close(): {exception}")
  else:
    print("Successfully disconnected from Postgres Database")

And here is an example of how to perform a fetchall query with no error handling.

#!/usr/bin/python3
import psycopg2

db_name = "mydb"
db_host = "10.11.12.13"
db_user = "john.doe"
db_pass = "itsasecret"
db_port = "5432"

connection = psycopg2.connect(database=db_name,
                        host=db_host,
                        user=db_user,
                        password=db_pass,
                        port=db_port)

cursor  = connection.cursor()
cursor.execute("select * from mytable")
results = cursor.fetchall()

for row in results:
  print(f"row 0 = {row[0]}")
  print(f"row 1 = {row[1]}")
  print(f"row 2 = {row[2]}")

cursor.close()
connection.close()

And here is an example of how to perform a fetchone query with no error handling.

#!/usr/bin/python3
import psycopg2

db_name = "mydb"
db_host = "10.11.12.13"
db_user = "john.doe"
db_pass = "itsasecret"
db_port = "5432"

connection = psycopg2.connect(database=db_name,
                        host=db_host,
                        user=db_user,
                        password=db_pass,
                        port=db_port)

cursor  = connection.cursor()
cursor.execute("select * from mytable")
result = cursor.fetchone()

print(f"result = {result}")
print(f"result[0] = {result[0]}")
print(f"result[1] = {result[1]}")

cursor.close()
connection.close()

And here is an example of how to perform a statement with no error handling..

#!/usr/bin/python3
import psycopg2
from datetime import datetime

db_name = "mydb"
db_host = "10.11.12.13"
db_user = "john.doe"
db_pass = "itsasecret"
db_port = "5432"

connection = psycopg2.connect(database=db_name,
                        host=db_host,
                        user=db_user,
                        password=db_pass,
                        port=db_port)

cursor    = connection.cursor()
statement = cursor.execute("update mytable set timestamp='{datetime.utcnow()}'")
connection.commit()
cursor.close()
connection.close()

And here is an example of how you can loop through the results.

#!/usr/bin/python3
import psycopg2

db_name = "mydb"
db_host = "10.11.12.13"
db_user = "john.doe"
db_pass = "itsasecret"
db_port = "5432"

connection = psycopg2.connect(database=db_name,
                        host=db_host,
                        user=db_user,
                        password=db_pass,
                        port=db_port)

cursor  = connection.cursor()
cursor.execute("select * from mytable")
result = cursor.fetchone()

for row in result:
  print(f"row[0] = {row[0]}")
  print(f"row[1] = {row[1]}")
  print(f"row[2] = {row[2]}")    

cursor.close()
connection.close()