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Computer Science

(i) Give one difference between alternate key and candidate key.

(ii) Sartaj has created a table named Student in MYSQL database, SCHOOL:

  • rno(Roll number )- integer
  • name(Name) - string
  • DOB (Date of birth) – Date
  • Fee – float

Note the following to establish connectivity between Python and MySQL:

  • Username - root
  • Password - tiger
  • Host - localhost

Sartaj, now wants to display the records of students whose fee is more than 5000. Help Sartaj to write the program in Python.

Python MySQL

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Answer

(i) One difference between alternate key and candidate key:

Alternate KeyCandidate Key
A candidate key is a set of attributes (columns) in a table that uniquely identifies each record or row.An alternate key is a set of attributes (columns) in a table that uniquely identifies each record but is not designated as the primary key.

(ii)

import mysql.connector as mysql
con1 = mysql.connect(host = "localhost",
                     user = "root",
                     password = "tiger",
                     database = "SCHOOL")
mycursor = con1.cursor()
query = "SELECT * FROM student WHERE fee > {}".format(5000)
mycursor.execute(query)
data = mycursor.fetchall()
for rec in data:
    print(rec)
con1.close()

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