MySQL Databases With Python Tutorial - YouTube

Python Connect MySQL Database

Python Connect MySQL Database

Databases are critical for storing and processing data even if you consider a powerful programming language like Python. Ever wondered where does this whole large set of data is stored in or fetched from?

Databases are critical for storing and processing data even if you consider a powerful programming language like Python. Ever wondered where does this whole large set of data is stored in or fetched from?

In this article, I’ll talk about the same and take you through the following aspects in detail.

  •        What is a [database](https://morioh.com/topic/database "database")?
    
  •        What is [MySQLdb](https://morioh.com/topic/mysql "MySQLdb")?
    
  •        How does [Python](https://morioh.com/topic/python "Python") connect to a database?
    
  •        Creating a Database
    
  •        Database Operations-[CRUD](https://morioh.com/p/60b941830c01 "CRUD")
    

Let’s get started :)

What is a database?

A database is basically a collection of structured data in such a way that it can easily be retrieved, managed and accessed in various ways. One of the simplest forms of databases is a text database. Relational databases are the most popular database system which includes the following:

Among all these databases, MySQL is one of the easiest databases to work with. Let me walk you through about this in detail.

What is MySQLdb?

MySQLdb is an open-source freely available relational database management system that uses Structured Query Language. Now one of the most important question here is “What is SQL?”

SQL (Structured Query Language) is a standard language for relational databases that allow users to do various operations on data like, Manipulating, Creating, Dropping, etc. In a nutshell, SQL allows you to do anything with the data.

Let’s move ahead and dive deep into Python database connection wherein you will learn how to connect with the database.

**How does Python connect to a database? **

It is very simple to connect Python with the database. Refer the below image which illustrates a Python connection with the database where how a connection request is sent to MySQL connector Python, gets accepted from the database and cursor is executed with result data.

Before connecting to the MySQL database, make sure you have MySQL installer installed on your computer. It provides a comprehensive set of tools which helps in installing MySQL with the following components:
MySQL server All available connectorsMySQL WorkbenchMySQL NotifierTools for Excel and Microsoft Visual StudioMySQL Sample DatabasesMySQL Documentation
To download the MySQL installer please go through the following video which talks about the various steps that you need to follow while installing MySQL.

Before proceeding you should make sure you have MySQL db installed on your computer. Refer the below commands for installing MySQL in command prompt and pycharm:

Using Pip:

Command:

pip install mysql-connector

**Using Pycharm **

Command:

import mysql.connector

Output:

C:UsersHarshit_KantPycharmProjectstest1venvScriptspython.exe C:/Users/Harshit_Kant/PycharmProjects/test1/venv/python-db-conn.py

Process finished with exit code 0

Moving on in this article with Python Database Connection let us see the parameters required to connect to the database:

  • **Username- It is simply the username you give to work MySQL server with, the Default username is root.
  • **Password- **Password is given by the user when you have installed the MySQL database. I am giving password here as ‘password123’
  • Host Name- This basically is the server name or IP address on which your MySQL is running, If it is a ‘localhost’, then your IP address is 127.0.0.0

I will show you from a coding perspective to connect python with MySQL database.

Example:

import mysql.connector
 
mydb=mysql.connector.connect(host="localhost",user="root",passwd="password123") // I have used 'host','username','password'
 
print(mydb)

Output:

C:UsersHarshit_KantPycharmProjectstest1venvScriptspython.exe C:/Users/Harshit_Kant/PycharmProjects/test1/venv/python-db-conn.py

<mysql.connector.connection_cext.CMySQLConnection object at 0x000001606D7BD6A0>

Process finished with exit code 0

**Explanation: **Here ‘mydb’ is just an instance. From the output, you can clearly see that it has connected to the database.

Next up in Python Database Connection, you will learn how to create a database.

Creating a Database:

Once the database connection is established, you are ready to create your own database which will be acting as a bridge between your python and MySQL server.

Let’s see the implementation part of it.

Example:

import mysql.connector
 
mydb=mysql.connector.connect(host="localhost",user="root",passwd="password123")
mycursor=mydb.cursor()
mycursor.execute("create database harshdb")

Output:

C:/Users/Harshit_Kant/PycharmProjects/test1/venv/python-db-conn.py

Process finished with exit code 0

Explanation:

  • In the above program, I have made use of cursor which is basically an object that is used to communicate to your entire MySQL server through which I am able to create my own database.
  • You can see from the output that my database with the name”harshdb” is created which is custom, as you can give any name to your database.

If you want to see the databases in your MySQL server, you can implement the following piece of code in pycharm:

Example :

import mysql.connector
 
mydb=mysql.connector.connect(host="localhost",user="root",passwd="password123")
mycursor=mydb.cursor()
mycursor.execute("show databases")
 
for db in mycursor:
print(db)

Output:

C:UsersHarshit_KantPycharmProjectstest1venvScriptspython.exe C:/Users/Harshit_Kant/PycharmProjects/test1/venv/python-db-conn.py

(‘harshdb’,)

(‘information_schema’,)

(‘mysql’,)

(‘performance_schema’,)

(‘sakila’,)

(‘sys’,)

(‘world’,)

Process finished with exit code 0

Explanation:

  • By implementing the above-written code I have tried showing all the databases which are existing in MySQL server.

Now that you have created your database, let’s dive deep into one of the most important aspects of Python Database Connection by doing few operations in it. Let us understand this in detail.

Database Operations[CRUD]:

There are numerous operations a programmer can perform using databases and SQL in order to have sound knowledge of database programming and MySQL.

I have demonstrated the CRUD operations below

  • Create– It is an SQL statement used to create a record in the table or can say it is used for creating a table.
  • **Read- **It is used for fetching useful information from the database.
  • **Update- **This particular SQL statement is used for updating the records in the table or updating the table.
  • **Delete- **As the name itself justifies this command is used for deleting the table.

Let us look at each aspect in detail from the coding perspective.

Create Operation:

import mysql.connector
 
mydb=mysql.connector.connect(host="localhost",user="root",passwd="password123",database=harshdb)
 
mycursor=mydb.cursor()
 
mycursor.execute("create table employee(name varchar(250),sal int(20))")

Output:

C:UsersHarshit_KantPycharmProjectstest1venvScriptspython.exe C:/Users/Harshit_Kant/PycharmProjects/test1/venv/python-db-conn.py

Process finished with exit code 0

Explanation:

  • In the above-given program, I have created a table ’employee’.
  • Table employee has two fields ‘name’ and ‘sal’.
  • Here, the User id is “root” and Password is “password123” used for accessing harshdb.

Below given Screenshot shows the table ’employee’ and returns the fields ‘name’ and ‘sal’.

In order to see the table which I have created, refer to the following code in python

import mysql.connector
 
mydb=mysql.connector.connect(host="localhost",user="root",passwd="password123",database="harshdb")
mycursor=mydb.cursor()
mycursor.execute("show tables")
 
for tb in mycursor:
    print(tb)

Output:

C:UsersHarshit_KantPycharmProjectstest1venvScriptspython.exe C:/Users/Harshit_Kant/PycharmProjects/test1/venv/python-db-conn.py

(’employee’,)

Process finished with exit code 0

Below given Screenshot shows the table ’employee’ which I have created.

Screenshot:

Now that you have seen how a table is created, let us look at how a user can fetch values from it.

Read Operation:

This particular operation happens in various stages. In order to do that first stage is to populate the table.

Code:

import mysql.connector
 
mydb=mysql.connector.connect(host="localhost",user="root",passwd="password123",database="harshdb")
mycursor=mydb.cursor()
 
sqlformula = "Insert into employee(name,sal) values(%s,%s)"//'values has placeholders
 
employees = [("harshit",200000),("rahul", 30000),("avinash", 40000),("amit", 50000),]//Created an array of emplpoyees
 
 
mycursor.executemany(sqlformula, employees)//Passing the data
 
mydb.commit()//SQL statement used for saving the changes

Output:

C:UsersHarshit_KantPycharmProjectstest1venvScriptspython.exe C:/Users/Harshit_Kant/PycharmProjects/test1/venv/python-db-conn.py

Process finished with exit code 0

In the above code, I have populated the data by using an array of employees by writing SQL statements in Python. Below a screenshot of the database will show the changes

Here,’harshit’ is used two times in the record while created the array.

**Stage 2: **In this stage, we will make use of the “select” SQL statement where the actual read operation will take place.

  • fetchall()– This particular function fetches all the data from the last executed statement.
  • **fetchone()- **This particular statement fetches one data from the last executed statement.

Code:

import mysql.connector
 
mydb=mysql.connector.connect(host="localhost",user="root",passwd="password123",database="harshdb")
mycursor=mydb.cursor()
 
mycursor.execute("select * from employee")
 
myresult = mycursor.fetchall()
 
for row in myresult:
    print(row)

Output:

(‘harshit’, 200000)

(‘harshit’, 200000)

(‘rahul’, 30000)

(‘avinash’, 40000)

(‘amit’, 50000)

Process finished with exit code 0

**Explanation: **In the above code we have made use of the function ‘fetchall()’. It fetches all the data from the last executed statement.

Given below is the screenshot of the database.

Code:

import mysql.connector
 
mydb=mysql.connector.connect(host="localhost",user="root",passwd="password123",database="harshdb")
mycursor=mydb.cursor()
 
mycursor.execute("select name from employee")//selecting the field i want data to be fetched from
 
myresult = mycursor.fetchone()
 
for row in myresult:
    print(row)

Output:

C:UsersHarshit_KantPycharmProjectstest1venvScriptspython.exe C:/Users/Harshit_Kant/PycharmProjects/test1/venv/python-db-conn.py

harshit

Process finished with exit code 0

**Explanation: **In the above code, I have made use of the function “fetchone()” which basically fetches a single data from the last executed statement.

That was all about ‘Read operation’, let’s dive deep into Update operation.

Update Operation:

This SQL statement is used for updating the records in the table. Let’s implement the code and see how the changes are taking place.

Code:

import mysql.connector
 
mydb=mysql.connector.connect(host="localhost",user="root",passwd="password123",database="harshdb")
mycursor=mydb.cursor()
 
sql = "Update employee SET sal = 70000 WHERE name = 'harshit'"
 
mycursor.execute(sql)
 
mydb.commit()

Output:

C:UsersHarshit_KantPycharmProjectstest1venvScriptspython.exe C:/Users/Harshit_Kant/PycharmProjects/test1/venv/python-db-conn.py

Process finished with exit code 0

**Explanation: **We have updated the row “sal” of record harshit in the above-given code. Below given Screenshot will give you a clear picture.

Screenshot:

As you can clearly see row ‘sal’ of record ‘harshit’ is updated to 70000.

This was all about Update operation, moving on with “Python Connect MySQL Database” article we will see the last operation which is ‘delete’.

Delete Operation:

As the name itself justifies, Delete operation is used for the deletion of records from the table. Let’s understand it from a coding perspective.

Code:

import mysql.connector
 
mydb=mysql.connector.connect(host="localhost",user="root",passwd="password123",database="harshdb")
mycursor=mydb.cursor()
 
sql = "DELETE FROM employee  WHERE name = 'harshit'"
 
mycursor.execute(sql)
 
mydb.commit()

Output:

C:UsersHarshit_KantPycharmProjectstest1venvScriptspython.exe C:/Users/Harshit_Kant/PycharmProjects/test1/venv/python-db-conn.py

Process finished with exit code 0

**Explanation: **In the above code I have deleted a record ‘harshit’ as it was repeated twice.

Below given screenshot will give you a better picture.

As you can clearly see from the screenshot record ‘harshit’ has been deleted. Well, you can do another set of manipulation from the delete operation itself like deleting salary. I had mentioned only two fields so the operations on the record which I could do is limited, but you can create more fields under the same table ’employee’ or any other table you create.

This brings us to the end of our article on “Python Connect MySQL Database”. I hope you are clear with all the concepts related to database, MYSQL db, database operations in python. Make sure you practice as much as possible and revert your experience.

How to Implement CRUD operations in Python on MySQL

How to Implement CRUD operations in Python on MySQL

In this post, we will see how to implement CRUD operations on MySQL

This post demonstrates how to implement CRUD operations in Python language on a MySQL database.

Python supports most of the popular databases to work with and implement CRUD operations. Some of the popular databases include:

  • MySQL
  • Oracle
  • PostgreSQL
  • Microsoft SQL Server 2000
  • Sybase
MySQL Database

If you want to work with CRUD operations in Python, first of all, download and install MySQL Database. If you already have a database, skip this step.

Go to below link and download MySQL Database: https://www.mysql.com/downloads/

Install MySQL Connector Driver

Python needs MySQL Connector Driver to access a MySQL Database. Follow the below steps to install the drive

STEP 1:

Open Command Prompt and navigate your pip.exe folder path.

By default pip folder path is: C:\Users\Acer\AppData\Local\Programs\Python\Python37-32\Scripts

STEP 2:

Type the below command and press Enter:

C:\Users\Acer\AppData\Local\Programs\Python\Python37-32\Scripts>pip install mysql-connector-python

After successful installation, exit from the command prompt**.**

Create Database

The following code snippet creates a new database. If you already have a database, you may skip this step. The database is created on the local server. You may want to use your server name, user id, and password.

To create a new database, we use CREATE Database SQL query.

The cursor() method creates a cursor object that is used to execute a SQL query by using the execute method. Once the database object is used, we need to close it.

import mysql.connector #Importing Connector package   
mysqldb=mysql.connector.connect(host="localhost",user="root",password="")#established connection   
mycursor=mysqldb.cursor()#cursor() method create a cursor object  
mycursor.execute("create database dbpython")#Execute SQL Query to create a database    
mysqldb.close()#Connection Close  
Create a table

The following code snippet creates a new database table using CREATE TABLE SQL query.

#Create a table into dbpython database  
import mysql.connector  
mysqldb=mysql.connector.connect(host="localhost",user="root",password="",database="dbpython")#established connection between your database   
mycursor=mysqldb.cursor()#cursor() method create a cursor object  
mycursor.execute("create table student(roll INT,name VARCHAR(255), marks INT)")#Execute SQL Query to create a table into your database  
mysqldb.close()#Connection Close  
Insert Record

The INSERT INTO SQL query adds new records to the table.

mysqldb.commit() method commits the changes to the database.

import mysql.connector  
mysqldb=mysql.connector.connect(host="localhost",user="root",password="",database="dbpython")#established connection between your database  
mycursor=mysqldb.cursor()#cursor() method create a cursor object    
try:  
   #Execute SQL Query to insert record  
   mycursor.execute("insert into student values(1,'Sarfaraj',80),(2,'Kumar',89),(3,'Sohan',90)")  
   mysqldb.commit() # Commit is used for your changes in the database  
   print('Record inserted successfully...')   
except:  
   # rollback used for if any error   
   mysqldb.rollback()  
mysqldb.close()#Connection Close  
Display Record

The following code uses a SELECT * SQL query to select data from a database table. The resultset is stored using cursor.fetchall() method.

import mysql.connector  
mysqldb=mysql.connector.connect(host="localhost",user="root",password="",database="dbpython")#established connection between your database  
mycursor=mysqldb.cursor()#cursor() method create a cursor object  
try:  
   mycursor.execute("select * from student")#Execute SQL Query to select all record   
   result=mycursor.fetchall() #fetches all the rows in a result set   
   for i in result:    
      roll=i[0]  
      name=i[1]  
      marks=i[2]  
      print(roll,name,marks)  
except:   
   print('Error:Unable to fetch data.')  
mysqldb.close()#Connection Close  

Note: If you want to fetch a single record then use fetchone() method

Update Record

The following code uses an UPDATE SQL query to update an existing record.

import mysql.connector  
mysqldb=mysql.connector.connect(host="localhost",user="root",password="",database="dbpython")#established connection between your database  
mycursor=mysqldb.cursor()#cursor() method create a cursor object  
try:  
   mycursor.execute("UPDATE student SET name='Ramu', marks=100 WHERE roll=1")#Execute SQL Query to update record
   mysqldb.commit() # Commit is used for your changes in the database  
   print('Record updated successfully...')   
except:   
   # rollback used for if any error  
   mysqldb.rollback()  
mysqldb.close()#Connection Close  
Delete Record

The following code uses a DELETE SQL query to delete a record from the table.

import mysql.connector   
mysqldb=mysql.connector.connect(host="localhost",user="root",password="",database="dbpython")#established connection between your database  
mycursor=mysqldb.cursor()#cursor() method create a cursor object   
try:   
   mycursor.execute("DELETE FROM student WHERE roll=3")#Execute SQL Query to detete a record   
   mysqldb.commit() # Commit is used for your changes in the database  
   print('Record deteted successfully...')  
except:  
   # rollback used for if any error  
   mysqldb.rollback()  
mysqldb.close()#Connection Close  
Summary

In this post, I covered MySQL database operations (create database, create table, insert, display, update and delete) with Python and MySQL Connector driver. Thank you for reading!