Tutorial

Python database access modules all have similar interfaces, described by the DBAPI. Most relational databases use the same synchronous interface, aiomysql tries to provide same api you just need to use await conn.f() instead of just call conn.f() for every method.

Installation

pip3 install aiomysql

Note

aiomysql requires PyMySQL library.

Getting Started

Lets start from basic example:

import asyncio
import aiomysql

loop = asyncio.get_event_loop()

async def test_example():
    conn = await aiomysql.connect(host='127.0.0.1', port=3306,
                                       user='root', password='', db='mysql',
                                       loop=loop)

    cur = await conn.cursor()
    await cur.execute("SELECT Host,User FROM user")
    print(cur.description)
    r = await cur.fetchall()
    print(r)
    await cur.close()
    conn.close()

loop.run_until_complete(test_example())

Connection is established by invoking the connect() coroutine, arguments list are keyword arguments, almost same as in PyMySQL corresponding method. Example makes connection to MySQL server on local host to access mysql database with user name root’ and empty password.

If connect() coroutine succeeds, it returns a Connection instance as the basis for further interaction with MySQL.

After the connection object has been obtained, code in example invokes Connection.cursor() coroutine method to create a cursor object for processing statements. Example uses cursor to issue a SELECT Host,User FROM user; statement, which returns a list of host and user from MySQL system table user:

cur = await conn.cursor()
await cur.execute("SELECT Host,User FROM user")
print(cur.description)
r = await cur.fetchall()

The cursor object’s Cursor.execute() method sends the query the server and Cursor.fetchall() retrieves rows.

Finally, the script invokes Cursor.close() coroutine and connection object’s Connection.close() method to disconnect from the server:

await cur.close()
conn.close()

After that, conn becomes invalid and should not be used to access the server.

Inserting Data

Let’s take basic example of Cursor.execute() method:

import asyncio
import aiomysql


async def test_example_execute(loop):
    conn = await aiomysql.connect(host='127.0.0.1', port=3306,
                                       user='root', password='',
                                       db='test_pymysql', loop=loop)

    cur = await conn.cursor()
    async with conn.cursor() as cur:
        await cur.execute("DROP TABLE IF EXISTS music_style;")
        await cur.execute("""CREATE TABLE music_style
                                  (id INT,
                                  name VARCHAR(255),
                                  PRIMARY KEY (id));""")
        await conn.commit()

        # insert 3 rows one by one
        await cur.execute("INSERT INTO music_style VALUES(1,'heavy metal')")
        await cur.execute("INSERT INTO music_style VALUES(2,'death metal');")
        await cur.execute("INSERT INTO music_style VALUES(3,'power metal');")
        await conn.commit()

    conn.close()


loop = asyncio.get_event_loop()
loop.run_until_complete(test_example_execute(loop))

Please note that you need to manually call commit() bound to your Connection object, because by default it’s set to False or in aiomysql.connect() you can transfer addition keyword argument autocommit=True.

Example with autocommit=True:

import asyncio
import aiomysql


async def test_example_execute(loop):
    conn = await aiomysql.connect(host='127.0.0.1', port=3306,
                                       user='root', password='',
                                       db='test_pymysql', loop=loop,
                                       autocommit=True)

    cur = await conn.cursor()
    async with conn.cursor() as cur:
        await cur.execute("DROP TABLE IF EXISTS music_style;")
        await cur.execute("""CREATE TABLE music_style
                                  (id INT,
                                  name VARCHAR(255),
                                  PRIMARY KEY (id));""")

        # insert 3 rows one by one
        await cur.execute("INSERT INTO music_style VALUES(1,'heavy metal')")
        await cur.execute("INSERT INTO music_style VALUES(2,'death metal');")
        await cur.execute("INSERT INTO music_style VALUES(3,'power metal');")

    conn.close()


loop = asyncio.get_event_loop()
loop.run_until_complete(test_example_execute(loop))