Database READ Operation in Python

PythonServer Side ProgrammingProgramming

READ Operation on any database means to fetch some useful information from the database.

Once our database connection is established, you are ready to make a query into this database. You can use either fetchone() method to fetch single record or fetchall() method to fetech multiple values from a database table.

  • fetchone() − It fetches the next row of a query result set. A result set is an object that is returned when a cursor object is used to query a table.
  • fetchall() − It fetches all the rows in a result set. If some rows have already been extracted from the result set, then it retrieves the remaining rows from the result set.
  • rowcount − This is a read-only attribute and returns the number of rows that were affected by an execute() method.


The following procedure queries all the records from EMPLOYEE table having salary more than 1000 −

import MySQLdb
# Open database connection
db = MySQLdb.connect("localhost","testuser","test123","TESTDB" )
# prepare a cursor object using cursor() method
cursor = db.cursor()
   WHERE INCOME > '%d'" % (1000)
   # Execute the SQL command
   # Fetch all the rows in a list of lists.
   results = cursor.fetchall()
   for row in results:
      fname = row[0]
      lname = row[1]
      age = row[2]
      sex = row[3]
      income = row[4]
      # Now print fetched result
      print "fname=%s,lname=%s,age=%d,sex=%s,income=%d" % \ (fname, lname, age, sex, income )
   print "Error: unable to fecth data"
# disconnect from server


This will produce the following result −

fname=Mac, lname=Mohan, age=20, sex=M, income=2000
Updated on 31-Jan-2020 09:58:22