Как подключиться к базе данных mysql python

Как подключиться к базе данных mysql python

To check everything is going well

1. start Ampps server
2. run the following python code

previously we implemented many tables on ampps server lets check if they existed: you should see all databases implemented on your ampps

Create with python mysql

1. create new database

Now you can open ampps:phpmyadmin you will find the new database

1. create table on the new database

Note we added new argument database in the connect function to address specific database.

to check table existence enter the following code to lst all tables in the specified database.

Insert statement: python mysql

1. insert one raw

1. mulitple raws

Select statement: python mysql

Two main keywords:

1. mycursor.fetchone(): to fetch nly one raw from the database from the top of the selected table
2. mycursor.fetchall(): to fetch all records matches the select statement criteria

Update statement: python mysql

Delete statement: python mysql

Note you can try all what you have learns in mysql tutorials to find out the differences

Convert selected data to json format

Json: In computing, JavaScript Object Notation (JSON) is an open-standard file format that uses human-readable text to transmit data objects consisting of attribute–value pairs and array data types. It is a very common data format, with a diverse range of applications, such as serving as replacement for XML in AJAX systems.

Json example: if we examined data we inserted in table demo and rewrite it in jsn format it will look like

it appears to be a list of dictionaries with all the records from the database. Here is the conde to convert the data to json format

Python server

Now we need a running server to recieve user request using jason and send back resulted jason file.

First, wee need to install python server. recommended flask

to make sure of the installation run the following code

now open your browser and write locahost

Lets send out demo table data from server to the browser

Moreover next class ISA.

About

These pages contain online teaching materials prepared by teaching assistants in the biomedical engineering department at Cairo University.

Introduction:

If you’re looking for an introduction to basic SQL queries, please read this post.

Connect to mysql using sql connector:

The connection to mysql can be established using mysql-connector-python library.

Connect to mysql using MySQLConnectionPool:

• The mysql.connector.pooling module implements pooling.
• A pool opens a number of connections and handles thread safety when providing connections to requesters.
• The size of a connection pool is configurable at pool creation time. It cannot be resized thereafter.
• A connection pool can be named at pool creation time. If no name is given, one is generated using the connection parameters.
• The connection pool name can be retrieved from the connection pool or connections obtained from it.
• To release a pooled connection obtained from a connection pool, invoke its close() method, just as for any unpooled connection. However, for a pooled connection, close() does not actually close the connection but returns it to the pool and makes it available for subsequent connection requests.

Connect to mysql using SQLAlchemy:

In most of the projects, we will be using an ORM predominantly to connect to databases. ORMs are not only convenient but also database agnostic which means less code change. The only changes may be the connection string or driver.

How do I connect to a MySQL Database in Python?

How do I connect to a MySQL database using a python program?

26 Answers 26

Connecting to MYSQL with Python 2 in three steps

1 — Setting

You must install a MySQL driver before doing anything. Unlike PHP, Only the SQLite driver is installed by default with Python. The most used package to do so is MySQLdb but it’s hard to install it using easy_install. Please note MySQLdb only supports Python 2.

For Windows user, you can get an exe of MySQLdb.

For Linux, this is a casual package (python-mysqldb). (You can use sudo apt-get install python-mysqldb (for debian based distros), yum install MySQL-python (for rpm-based), or dnf install python-mysql (for modern fedora distro) in command line to download.)

2 — Usage

After installing, Reboot. This is not mandatory, But it will prevent me from answering 3 or 4 other questions in this post if something goes wrong. So please reboot.

Then it is just like using any other package :

Of course, there are thousand of possibilities and options; this is a very basic example. You will have to look at the documentation. A good starting point.

3 — More advanced usage

Once you know how it works, You may want to use an ORM to avoid writing SQL manually and manipulate your tables as they were Python objects. The most famous ORM in the Python community is SQLAlchemy.

I strongly advise you to use it: your life is going to be much easier.

I recently discovered another jewel in the Python world: peewee. It’s a very lite ORM, really easy and fast to setup then use. It makes my day for small projects or stand alone apps, Where using big tools like SQLAlchemy or Django is overkill :

This example works out of the box. Nothing other than having peewee ( pip install peewee ) is required.

Here’s one way to do it, using MySQLdb, which only supports Python 2:

If you do not need MySQLdb, but would accept any library, I would very, very much recommend MySQL Connector/Python from MySQL: http://dev.mysql.com/downloads/connector/python/.

It is one package (around 110k), pure Python, so it is system independent, and dead simple to install. You just download, double-click, confirm license agreement and go. There is no need for Xcode, MacPorts, compiling, restarting …

Then you connect like:

Oracle (MySQL) now supports a pure Python connector. That means no binaries to install: it’s just a Python library. It’s called "Connector/Python".

After installations, you can see some usage examples here

Stop Using MySQLDb if you want to avoid installing mysql headers just to access mysql from python.

Use pymysql. It does all of what MySQLDb does, but it was implemented purely in Python with NO External Dependencies. This makes the installation process on all operating systems consistent and easy. pymysql is a drop in replacement for MySQLDb and IMHO there is no reason to ever use MySQLDb for anything. EVER! — PTSD from installing MySQLDb on Mac OSX and *Nix systems , but that’s just me.

Installation

pip install pymysql

That’s it. you are ready to play.

Example usage from pymysql Github repo

ALSO — Replace MySQLdb in existing code quickly and transparently

If you have existing code that uses MySQLdb, you can easily replace it with pymysql using this simple process:

All subsequent references to MySQLdb will use pymysql transparently.

Try using MySQLdb. MySQLdb only supports Python 2.

Run this command in your terminal to install mysql connector:

And run this in your python editor to connect to MySQL:

Samples to execute MySQL Commands (in your python edior):

For newer versions of Python (>=3.6)

For older versions of Python (<3.7, 2.4 <= Python <= 2.7)

If you are working on an older version of Python (unfortunately), then you could also try out -> oursql.

Please note however, that the project is no longer maintained, and bug fixes are not being pushed either.

As a db driver, there is also oursql. Some of the reasons listed on that link, which say why oursql is better:

• oursql has real parameterization, sending the SQL and data to MySQL completely separately.

• oursql allows text or binary data to be streamed into the database and streamed out of the database, instead of requiring everything to be buffered in the client.
• oursql can both insert rows lazily and fetch rows lazily.
• oursql has unicode support on by default.
• oursql supports python 2.4 through 2.7 without any deprecation warnings on 2.6+ (see PEP 218) and without completely failing on 2.7 (see PEP 328).
• oursql runs natively on python 3.x.

So how to connect to mysql with oursql?

Very similar to mysqldb:

And of course for ORM SQLAlchemy is a good choice, as already mentioned in the other answers.

SqlAlchemy

SQLAlchemy is the Python SQL toolkit and Object Relational Mapper that gives application developers the full power and flexibility of SQL. SQLAlchemy provides a full suite of well known enterprise-level persistence patterns, designed for efficient and high-performing database access, adapted into a simple and Pythonic domain language.

Installation

RAW query

ORM way

Best way to connect to MySQL from python is to Use MySQL Connector/Python because it is official Oracle driver for MySQL for working with Python and it works with both Python 3 and Python 2.

follow the steps mentioned below to connect MySQL

install connector using pip

pip install mysql-connector-python

Use connect() method of mysql connector python to connect to MySQL.pass the required argument to connect() method. i.e. Host, username, password, and database name.

Create cursor object from connection object returned by connect() method to execute SQL queries.

close the connection after your work completes.

Example:

Important API of MySQL Connector Python

For DML operations — Use cursor.execute() and cursor.executemany() to run query. and after this use connection.commit() to persist your changes to DB

To fetch data — Use cursor.execute() to run query and cursor.fetchall() , cursor.fetchone() , cursor.fetchmany(SIZE) to fetch data

Despite all answers above, in case you do not want to connect to a specific database upfront, for example, if you want to create the database still (!), you can use connection.select_db(database) , as demonstrated in the following.

Even though some of you may mark this as a duplicate and get upset that I am copying someone else’s answer, I would REALLY like to highlight an aspect of Mr. Napik’s response. Because I missed this, I caused nationwide website downtime (9min). If only someone shared this information, I could have prevented it!

Here is his code:

The important thing here is the Try and Finally clause. This allows connections to ALWAYS be closed, regardless of what happens in the cursor/sqlstatement portion of the code. A lot of active connections cause DBLoadNoCPU to spike and could crash a db server.

I hope this warning helps to save servers and ultimately jobs! 😀

MySQLdb is the straightforward way. You get to execute SQL queries over a connection. Period.

My preferred way, which is also pythonic, is to use the mighty SQLAlchemy instead. Here is a query related tutorial, and here is a tutorial on ORM capabilities of SQLALchemy.

for Python3.6 I found two driver: pymysql and mysqlclient. I tested the performance between them and got the result: the mysqlclient is faster.

below is my test process(need install python lib profilehooks to analyze time elapse：

raw sql: select * from FOO;

immediatly execute in mysql terminal: 46410 rows in set (0.10 sec)

here’s the pymysql profile:

here’s the mysqlclient profile:

So, it seems that mysqlclient is much faster than pymysql

Just a modification in above answer. Simply run this command to install mysql for python

remember! It is case sensitive.

mysqlclient is the best as others only provide support to specific versions of python

Also take a look at Storm. It is a simple SQL mapping tool which allows you to easily edit and create SQL entries without writing the queries.

Here is a simple example:

To find and object use:

Find with primary key:

For further information see the tutorial.

This is Mysql DB connection

PyMySQL 0.10.1 — Released: Sep 10, 2020, has support for python3 as well.

you can connect your python code to mysql in this way.

First step to get The Library: Open terminal and execute pip install mysql-python-connector . After the installation go the second step.

Second Step to import the library: Open your python file and write the following code: import mysql.connector

Third step to connect to the server: Write the following code:

conn = mysql.connector.connect(host= you host name like localhost or 127.0.0.1 , username= your username like root , password = your password )

Third step Making the cursor: Making a cursor makes it easy for us to run queries. To make the cursor use the following code: cursor = conn.cursor()

Executing queries: For executing queries you can do the following: cursor.execute(query)

If the query changes any thing in the table you need to add the following code after the execution of the query: conn.commit()

Getting values from a query: If you want to get values from a query then you can do the following: cursor.excecute(‘SELECT * FROM table_name ‘) for i in cursor: print(i) #Or for i in cursor.fetchall(): print(i)

The fetchall() method returns a list with many tuples that contain the values that you requested ,row after row .

2. MySQL with Python¶

The ‘mysql-connector’ is not supported by Django-framework. The good option is ‘mysqlclient’ which is supported by Django as well.

• Next, we need to create a database in MySQL. Let’s create a new database with name ‘pythonSQL’,

2.2. Connect and load data¶

Following code can be used to connect and load the data to database. Note that, the commands in the c.execute(…) statements are exactly same as the commands in the previous chapters.

• Next, run the above file to save the data in the database,

2.3. Read data from table¶

Following code can be used to read data from the table,

• To see the output, execute the code,

• In this way, we can get the data from the table and perform various operations on the data.
• Also, we can use all those queries with python, as queries in the execute statements are same as queries in previous chapter.

2.4. Connection in try-except block¶

We can use following code to put the connection string in the try except block, so that we can get proper message for not connecting with the database,