Hướng dẫn dùng w3schools mysql python

Python can be used in database applications.

One of the most popular databases is MySQL.

MySQL Database

To be able to experiment with the code examples in this tutorial, you should have MySQL installed on your computer.

You can download a free MySQL database at //www.mysql.com/downloads/.

Install MySQL Driver

Python needs a MySQL driver to access the MySQL database.

In this tutorial we will use the driver "MySQL Connector".

We recommend that you use PIP to install "MySQL Connector".

PIP is most likely already installed in your Python environment.

Navigate your command line to the location of PIP, and type the following:

Download and install "MySQL Connector":

C:\Users\Your Name\AppData\Local\Programs\Python\Python36-32\Scripts>python -m pip install mysql-connector-python

Now you have downloaded and installed a MySQL driver.

Test MySQL Connector

To test if the installation was successful, or if you already have "MySQL Connector" installed, create a Python page with the following content:

If the above code was executed with no errors, "MySQL Connector" is installed and ready to be used.

Create Connection

Start by creating a connection to the database.

Use the username and password from your MySQL database:

demo_mysql_connection.py:

import mysql.connector

mydb = mysql.connector.connect[
  host="localhost",
  user="yourusername",
  password="yourpassword"
]

print[mydb]

Run example »

Now you can start querying the database using SQL statements.

Python can be used in database applications.

One of the most popular databases is MySQL.

MySQL Database

To be able to experiment with the code examples in this tutorial, you should have MySQL installed on your computer.

You can download a free MySQL database at //www.mysql.com/downloads/.

Install MySQL Driver

Python needs a MySQL driver to access the MySQL database.

In this tutorial we will use the driver "MySQL Connector".

We recommend that you use PIP to install "MySQL Connector".

PIP is most likely already installed in your Python environment.

Navigate your command line to the location of PIP, and type the following:

Download and install "MySQL Connector":

C:\Users\Your Name\AppData\Local\Programs\Python\Python36-32\Scripts>python -m pip install mysql-connector-python

Now you have downloaded and installed a MySQL driver.

Test MySQL Connector

To test if the installation was successful, or if you already have "MySQL Connector" installed, create a Python page with the following content:

If the above code was executed with no errors, "MySQL Connector" is installed and ready to be used.

Create Connection

Start by creating a connection to the database.

Use the username and password from your MySQL database:

demo_mysql_connection.py:

import mysql.connector

mydb = mysql.connector.connect[
  host="localhost",
  user="yourusername",
  password="yourpassword"
]

print[mydb]

Run example »

Now you can start querying the database using SQL statements.

SQL is a standard language for storing, manipulating and retrieving data in databases.

Nội dung chính

• Examples in Each Chapter
• SQL Exercises
• Test Yourself With Exercises
• SQL Examples
• SQL Quiz Test
• My Learning
• SQL References
• SQL Data Types
• Kickstart your career
• Examples in Each Chapter
• MySQL Exercises
• Test Yourself With Exercises
• MySQL Examples
• MySQL Quiz Test
• My Learning
• MySQL References
• AJAX Database Example
• Example Explained - The MySQL Database
• Example Explained
• The PHP File

Our SQL tutorial will teach you how to use SQL in: MySQL, SQL Server, MS Access, Oracle, Sybase, Informix, Postgres, and other database systems.

Start learning SQL now »

Examples in Each Chapter

With our online SQL editor, you can edit the SQL statements, and click on a button to view the result.

Click on the "Try it Yourself" button to see how it works.

SQL Exercises

Test Yourself With Exercises

Exercise:

Insert the missing statement to get all the columns from the Customers table.

Start the Exercise

SQL Examples

Learn by examples! This tutorial supplements all explanations with clarifying examples.

See All SQL Examples

SQL Quiz Test

Test your SQL skills at W3Schools!

Start SQL Quiz!

My Learning

Track your progress with the free "My Learning" program here at W3Schools.

Log into your account, and start earning points!

This is an optional feature, you can study W3Schools without using My Learning.

SQL References

At W3Schools you will find a complete reference for keywords and function:

SQL Keyword Reference

MYSQL Functions

SQLServer Functions

MS Access Functions

SQL Quick Reference

SQL Data Types

Data types and ranges for Microsoft Access, MySQL and SQL Server.

SQL Data Types

Kickstart your career

Get certified by completing the course

Get certified

MySQL is a widely used relational database management system [RDBMS].

MySQL is free and open-source.

MySQL is ideal for both small and large applications.

Start learning MySQL now »

Examples in Each Chapter

With our online MySQL editor, you can edit the SQL statements, and click on a button to view the result.

Click on the "Try it Yourself" button to see how it works.

MySQL Exercises

Test Yourself With Exercises

Exercise:

Insert the missing statement to get all the columns from the Customers table.

Start the Exercise

MySQL Examples

Learn by examples! This tutorial supplements all explanations with clarifying examples.

See All SQL Examples

MySQL Quiz Test

Test your MySQL skills at W3Schools!

Start MySQL Quiz!

My Learning

Track your progress with the free "My Learning" program here at W3Schools.

Log into your account, and start earning points!

This is an optional feature, you can study W3Schools without using My Learning.

MySQL References

At W3Schools you will find a complete reference of MySQL data types and functions:

MySQL Data Types

MySQL Functions

AJAX can be used for interactive communication with a database.

AJAX Database Example

The following example will demonstrate how a web page can fetch information from a database with AJAX:

Example

Person info will be listed here...

Example Explained - The MySQL Database

The database table we use in the example above looks like this:

Example Explained

In the example above, when a user selects a person in the dropdown list above, a function called "showUser[]" is executed.

The function is triggered by the onchange event.

Here is the HTML code:

Example

function showUser[str] {
  if [str == ""] {
    document.getElementById["txtHint"].innerHTML = "";
    return;
  } else {
    var xmlhttp = new XMLHttpRequest[];
    xmlhttp.onreadystatechange = function[] {
      if [this.readyState == 4 && this.status == 200] {
        document.getElementById["txtHint"].innerHTML = this.responseText;
      }
    };
    xmlhttp.open["GET","getuser.php?q="+str,true];
    xmlhttp.send[];
  }
}

  Select a person:
  Peter Griffin
  Lois Griffin
  Joseph Swanson
  Glenn Quagmire
 

Run example »

Code explanation:

First, check if person is selected. If no person is selected [str == ""], clear the content of txtHint and exit the function. If a person is selected, do the following:

• Create an XMLHttpRequest object
• Create the function to be executed when the server response is ready
• Send the request off to a file on the server
• Notice that a parameter [q] is added to the URL [with the content of the dropdown list]

The PHP File

The page on the server called by the JavaScript above is a PHP file called "getuser.php".

The source code in "getuser.php" runs a query against a MySQL database, and returns the result in an HTML table:

table {
  width: 100%;
  border-collapse: collapse;
}

table, td, th {
  border: 1px solid black;
  padding: 5px;
}

th {text-align: left;}

Explanation: When the query is sent from the JavaScript to the PHP file, the following happens:

1. PHP opens a connection to a MySQL server
2. The correct person is found
3. An HTML table is created, filled with data, and sent back to the "txtHint" placeholder