Q.Consider the following SQL table MEMBER in a SQL Database CLUB: Table: MEMBER M_ID NAME ACTIVITY M1001 Amina GYM M1002 Pratik GYM M1003 Simon SWIMMING M1004 Rakesh GYM M1005 Avneet SWIMMING Assume that the required library for establishing the connection between Python and MYSQL is already imported in the given Python code. Also assume that DB is the name of the database connection for table MEMBER stored in the database CLUB. Predict the output of the following code: MYCUR = DB.cursor() MYCUR.execute("USE CLUB") MYCUR.execute("SELECT * FROM MEMBER WHERE ACTIVITY= 'GYM' ") R=MYCUR.fetchone() for i in range(2): R=MYCUR.fetchone() print(R[0], R[1], sep = "#")

The key idea here is understanding how a database cursor iterates through a result set using fetchone() and how loop structures in Python interact with this iteration — a classic CBSE Class 12 Computer Science Python-MySQL connectivity trace.

The SELECT * FROM MEMBER WHERE ACTIVITY = 'GYM' query retrieves rows where the ACTIVITY is 'GYM'. The result set, in table order, is:

1. ('M1001', 'Amina', 'GYM')

2. ('M1002', 'Pratik', 'GYM')

3. ('M1004', 'Rakesh', 'GYM')

4. R=MYCUR.fetchone() fetches the first row: ('M1001', 'Amina', 'GYM').

5. The for i in range(2): loop executes twice.

   • In the first iteration (i=0), R=MYCUR.fetchone() fetches the second row: ('M1002', 'Pratik', 'GYM').
   • In the second iteration (i=1), R=MYCUR.fetchone() fetches the third row: ('M1004', 'Rakesh', 'GYM'). …

When working with databases in Python, understanding how a cursor interacts with a result set is crucial. The fetchone() method is stateful; it retrieves one row at a time and advances an internal pointer to the next row in the result set. This means subsequent calls to fetchone() will return different rows until all rows are exhausted.

Let's break down the process:

1. Database Table and Query Result:

   First, let's visualize the MEMBER table and the result of the SQL query.

   Table: MEMBER

   M_ID	NAME	ACTIVITY
   M1001	Amina	GYM
   M1002	Pratik	GYM
   M1003	Simon	SWIMMING
   M1004	Rakesh	GYM
   M1005	Avneet	SWIMMING

   The SQL query SELECT * FROM MEMBER WHERE ACTIVITY = 'GYM' will filter the table to include only members whose ACTIVITY is 'GYM'. The result set, in the order they would typically be returned (assuming no specific ORDER BY clause, often by primary key or insertion order), would be:

   Result Set for ACTIVITY = 'GYM'

   M_ID	NAME	ACTIVITY
   M1001	Amina	GYM
   M1002	Pratik	GYM
   M1004	Rakesh	GYM

2. Code Execution Trace:

   • MYCUR = DB.cursor(): A cursor object, MYCUR, is created. This object is used to execute SQL commands and fetch results.

   • MYCUR.execute("USE CLUB"): This SQL command sets the active database context to CLUB. This is a preparatory step, ensuring subsequent queries operate on the correct database.

   • MYCUR.execute("SELECT * FROM MEMBER WHERE ACTIVITY= 'GYM' "): The SQL query is executed. The database processes this query and prepares the result set (the three rows listed above). The cursor's internal pointer is now positioned before the first row of this result set.

   • R = MYCUR.fetchone():

     This is the first call to fetchone(). It retrieves the first row from the result set.

     R now holds the tuple ('M1001', 'Amina', 'GYM').

     The cursor's internal pointer advances to the next row.

   • for i in range(2)::

     This loop will iterate twice, for i = 0 and i = 1.

     • Iteration 1 (i = 0): R = MYCUR.fetchone(): This is the second call to fetchone(). It retrieves the next available row from the result set. R now holds the tuple ('M1002', 'Pratik', 'GYM'). …