Python Update MySQL Table

This article demonstrates how to execute a MySQL UPDATE query from Python to modify the MySQL table’s data.

Goals of this lesson. You’ll learn the following MySQL UPDATE operations from Python using a ‘MySQL Connector’ module.

• Update single and multiple rows, single and multiple columns
• Use a Python variable in a parameterized query to update table rows.
• Also, Update a column with date-time and timestamp values
• The role of commit and rollback in the update operation.

Prerequisite

Before executing the following program, make sure you have the following in place −

• Username and password that you need to connect MySQL
• MySQL database table name which you want to update.

Example to Update a row of MySQL Table

To perform a SQL UPDATE query from Python, you need to follow the following steps: –

Let’s see the program now. In this program, we are updating a Laptop table by changing the price column of the first row.

import mysql.connector

try:
    connection = mysql.connector.connect(host='localhost',
                                         database='electronics',
                                         user='pynative',
                                         password='pynative@#29')
    cursor = connection.cursor()

    print("Before updating a record ")
    sql_select_query = """select * from Laptop where id = 1"""
    cursor.execute(sql_select_query)
    record = cursor.fetchone()
    print(record)

    # Update single record now
    sql_update_query = """Update Laptop set Price = 7000 where id = 1"""
    cursor.execute(sql_update_query)
    connection.commit()
    print("Record Updated successfully ")

    print("After updating record ")
    cursor.execute(sql_select_query)
    record = cursor.fetchone()
    print(record)

except mysql.connector.Error as error:
    print("Failed to update table record: {}".format(error))
finally:
    if connection.is_connected():
        connection.close()
        print("MySQL connection is closed")

Output:

Before updating a row
(1, 'Lenovo ThinkPad P71', 6459.0, datetime.date(2019, 8, 14))
Record Updated successfully 

After updating row
(1, 'Lenovo ThinkPad P71', 7000.0, datetime.date(2019, 8, 14))
MySQL connection is closed

Use a Python variable in MySQL Update query

Sometimes we need input from the user, such as when users update their password or any other details through User Interface. Or when you want to update details dynamically by passing Python variables into a query. Such as setting column value using the variable.

It is always best practice to use parameterized query and prepared statement, i.e., placeholders ( %s ) inside any SQL statements that contain input from users. This helps us prevent SQL injection and other SQL issues.
Read more on What is a Parameterized Query and its performance benefits.

Let’ s see the example program now.

import mysql.connector

def update_laptop_price(id, price):
    try:
        connection = mysql.connector.connect(host='localhost',
                                             database='electronics',
                                             user='roo',
                                             password='pynative@#29')

        cursor = connection.cursor()
        sql_update_query = """Update laptop set price = %s where id = %s"""
        input_data = (price, id)
        cursor.execute(sql_update_query, input_data)
        connection.commit()
        print("Record Updated successfully ")

    except mysql.connector.Error as error:
        print("Failed to update record to database: {}".format(error))
    finally:
        if connection.is_connected():
            cursor.close()
            connection.close()
            print("MySQL connection is closed")

update_laptop_price(7500, 1)
update_laptop_price(5000, 2)

Output: –

Record Updated successfully 
MySQL connection is closed
Record Updated successfully 
MySQL connection is closed

Let’s understand the above program: –

• We used the prepared statement to accept user input using a placeholder, i.e., we put two placeholders in the update query, one for the “Price” column and the other is for the” id” column.
• Next, we added those two columns value in the tuple format in sequential order and passed SQL update query and input tuple to the cursor.execute() method. Remember tuple contains user data in the sequential order of placeholders.
• In the end, we are committing our changes to the database using the connection.commit().

Update Multiple Rows of MySQL Table using Python

It is possible to update multiple rows in a single SQL Query. You can also call it a bulk update. Use the cursor.executemany() method of cursor object to update multiple rows of a table.

The syntax of the executemany() method

cursor.executemany(operation, seq_of_params)

This method executes operation against all parameter sequences in the sequence seq_of_params argument.

import mysql.connector

try:
    connection = mysql.connector.connect(host='localhost',
                                         database='electronics',
                                         user='pynative',
                                         password='pynative@#29')

    cursor = connection.cursor()
    sql_update_query = """Update Laptop set Price = %s where id = %s"""

    # multiple records to be updated in tuple format
    records_to_update = [(3000, 3), (2750, 4)]
    cursor.executemany(sql_update_query, records_to_update)
    connection.commit()

    print(cursor.rowcount, "Records of a laptop table updated successfully")

except mysql.connector.Error as error:
    print("Failed to update records to database: {}".format(error))
finally:
    if connection.is_connected():
        connection.close()
        print("MySQL connection is closed")

Output:

2 Records of a laptop table updated successfully
connection is closed

Let’s  understand the above program

• We defined a SQL update query with two placeholders (“Price” and “Id” column ). and prepared a list of records to be updated. This List contains a tuple for each row. Here we created two tuples, so we are updated two rows.
• We used the cursor.executemany() method to update multiple rows of a database table.
• Using the cursor.rowcount we can find how many rows are updated successfully.

Python update multiple Columns of MySQL table

We can also update multiple columns of the MySQL table in a single query. Use parameterized query using a placeholder to update multiple columns. Let see this with an example program.

import mysql.connector

try:
    connection = mysql.connector.connect(host='localhost',
                                         database='electronics',
                                         user='pynative',
                                         password='pynative@#29')

    cursor = connection.cursor()
    sql_update_query = """Update Laptop set Name = %s, Price = %s where id = %s"""

    name = "HP Pavilion"
    price = 2200
    id = 4
    input = (name, price, id)

    cursor.execute(sql_update_query, input)
    connection.commit()
    print("Multiple columns updated successfully ")

except mysql.connector.Error as error:
    print("Failed to update columns of table: {}".format(error))

finally:
    if connection.is_connected():
        connection.close()
        print("MySQL connection is closed")

Output:

Multiple column updated successfully
MySQL connection is closed

Update Datetime and timestamp column of a MySQL table from Python

Suppose you have a date column in a MySQL table and you want to update a datetime.datetime() object into this column. Let’s see how to prepare an update query to update the datetime column of a table

from datetime import datetime

import mysql.connector

try:
    connection = mysql.connector.connect(host='localhost',
                                         database='electronics',
                                         user='pynative',
                                         password='pynative@#29')

    cursor = connection.cursor()
    sql_update_query = """Update Laptop set Purchase_date = %s where id = %s"""

    current_Date = datetime.now()
    formatted_date = current_Date.strftime('%Y-%m-%d %H:%M:%S')
    id = 2
    input = (formatted_date, id)
    cursor.execute(sql_update_query, input)
    connection.commit()
    print("Purchased Date Updated successfully ")

except mysql.connector.Error as error:
    print("Failed to update purchased date {}".format(error))

finally:
    if connection.is_connected():
        connection.close()
        print("connection is closed")

You should get the following output after the execution of the above code.

Purchased Date Updated successfully 
connection is closed

Next Steps

To practice what you learned in this lesson, Please solve a Python Database Exercise project to practice and master the Python Database operations.