PYHON MYSQL CONNECTIVITY

What library is commonly used to connect Python to MySQL?

• mysql-db-connector

• mysql-connector-python

• MySQLdb

• pyMySQL

Answer explanation

The library 'mysql-connector-python' is the official MySQL driver for Python, providing a robust and easy way to connect to MySQL databases. While 'MySQLdb' and 'pyMySQL' are also used, 'mysql-connector-python' is the most commonly recommended.

How do you install the MySQL connector for Python?

• Run 'pip install mysql-connector-python' in your command line.

• Use 'apt-get install mysql-connector-python' in the terminal.

• Run 'npm install mysql-connector' in your command line.

• Download the MySQL connector from the official website.

Answer explanation

The correct way to install the MySQL connector for Python is by running 'pip install mysql-connector-python' in your command line, as 'pip' is the package manager for Python packages.

What is the purpose of the 'connect()' function in MySQL?

• To establish a connection to the MySQL database.

• To delete a connection from the MySQL database.

• To retrieve data from the MySQL database.

• To update records in the MySQL database.

Answer explanation

The 'connect()' function is used to establish a connection to the MySQL database, allowing subsequent operations like querying and updating data. This makes it the correct choice among the options provided.

How can you execute a SQL query using a cursor in Python?

• Use a cursor to execute SQL queries by creating a cursor object from a database connection and calling the execute() method on it.

• Use the fetchall() method to run SQL queries directly.

• Create a database connection without a cursor and execute queries directly.

• Use the print() function to display SQL query results.

Answer explanation

The correct choice explains that to execute a SQL query in Python, you need to create a cursor object from a database connection and use the execute() method. This is the standard approach for interacting with databases.

What is the command to commit changes to the database in Python?

• commit.transaction()

• db.saveChanges()

• connection.commit()

• connection.update()

Answer explanation

The correct command to commit changes to the database in Python is 'connection.commit()'. This method finalizes the current transaction, ensuring that all changes made during the transaction are saved to the database.

How do you handle exceptions when connecting to a MySQL database?

• Use a try-catch block to manage exceptions during the connection attempt.

• Use a switch statement to handle database connection errors.

• Ignore exceptions and proceed with the connection attempt.

• Log the error to a file without handling it in the code.

Answer explanation

Using a try-catch block is essential for managing exceptions when connecting to a MySQL database. It allows you to gracefully handle errors, ensuring your application can respond appropriately instead of crashing.

What is the difference between 'fetchone()' and 'fetchall()' methods?

• 'fetchone()' retrieves one record, while 'fetchall()' retrieves all records.

• 'fetchone()' retrieves multiple records, while 'fetchall()' retrieves none.

• Both 'fetchone()' and 'fetchall()' retrieve the same number of records.

• 'fetchone()' retrieves all records, while 'fetchall()' retrieves one record.

Answer explanation

The correct choice states that 'fetchone()' retrieves one record, while 'fetchall()' retrieves all records. This accurately describes the functionality of these methods in database operations.

How can you close a cursor and a connection in Python?

• cursor.disconnect(); connection.terminate();

• cursor.close(); connection.shutdown();

• cursor.end(); connection.closeConnection();

• cursor.close(); connection.close();

Answer explanation

To properly close a cursor and a connection in Python, use 'cursor.close(); connection.close();'. This ensures that resources are released correctly, unlike the other options which use incorrect method names.

What is the purpose of the 'DROP TABLE' SQL command?

• To create a new table in a database.

• To retrieve data from a table in a database.

• To remove a table and its data from a database.

• To update the data in an existing table.

Answer explanation

The 'DROP TABLE' SQL command is used to remove a table and all its data from a database, making it the correct choice. The other options describe different SQL commands for creating, retrieving, or updating data.

How do you create a new database using Python and MySQL?

• Use the MySQL connector to connect to the server and execute 'CREATE DATABASE database_name;'

• Use the SQLite library to create a new database.

• Run the command 'CREATE NEW DATABASE database_name;' in the MySQL shell.

• Connect to the server and use 'ADD DATABASE database_name;' command.

Answer explanation

The correct choice is to use the MySQL connector to connect to the server and execute 'CREATE DATABASE database_name;'. This is the standard SQL command for creating a new database in MySQL.