A python ORM like mybatis.
pip install -U mybatis
CREATE DATABASE mybatis;
USE mybatis;
CREATE TABLE IF NOT EXISTS fruits (
id INT AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(100),
category VARCHAR(100),
price int);
INSERT INTO fruits (name, category, price) VALUES ('Alice', 'A', 100);
INSERT INTO fruits (name, category, price) VALUES ('Bob', 'B', 200);CREATE TABLE if not exists fruits (
id SERIAL PRIMARY KEY,
name VARCHAR(100),
category VARCHAR(100),
price int);
INSERT INTO fruits (name, category, price) VALUES ('Alice', 'A', 100);
INSERT INTO fruits (name, category, price) VALUES ('Bob', 'B', 200);The example is as follows:
from mybatis import Mybatis, ConnectionFactory
conn = ConnectionFactory.get_connection(
dbms_name='mysql', # change to 'postgresql' if you are using PostgreSQL
host="localhost",
user="mybatis",
password="mybatis",
database="mybatis")
mb = Mybatis(conn, "mapper", cache_memory_limit=50*1024*1024)
@mb.SelectOne("SELECT * FROM fruits WHERE id=#{id}")
def get_one(id:int):
pass
@mb.SelectMany("SELECT * FROM fruits")
def get_many():
pass
@mb.Insert("INSERT INTO fruits (name, category, price) VALUES (#{name}, #{category}, #{price})", primary_key="id")
def insert(name:str, category:str, price:int):
pass
@mb.Delete("DELETE FROM fruits WHERE id=#{id}")
def delete(id:int):
pass
@mb.Update("UPDATE fruits SET name=#{name} WHERE id=#{id}")
def update(name:str, id:int):
pass
print(get_one(id=1))
print(delete(id=4))
print(get_many())
print(insert(name="Dating", category="D", price=20))
print(get_many())
print(update(name='Amazon', id=1))
print(get_many())refer to test_mybatis.py、test2.xml
Create a mapper directory, and create a file named mapper/test.xml, as follows:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper>
<insert id="testInsert1">
INSERT INTO fruits (name, category, price) VALUES (#{name}, #{category}, #{price})
<if test="'__need_returning_id__' in params">
RETURNING ${__need_returning_id__}
</if>
</insert>
<select id="testBasic1">
SELECT * from fruits where id=#{id}
</select>
</mapper>Create a Python file named "test.py" as follows:
from mybatis import *
def main():
conn = ConnectionFactory.get_connection(
dbms_name='mysql', # change to 'postgresql' if you are using PostgreSQL
host="localhost",
user="mybatis",
password="mybatis",
database="mybatis")
mb = Mybatis(conn, "mapper", cache_memory_limit=50*1024*1024)
ret = mb.insert('testInsert1', {'name':'Alice', 'category':'C', 'price':500})
ret = mb.select_one("testBasic1", {'id':1})
print(ret)
if __name__ == "__main__":
main()Create xml mapper as follows:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="test_namespace">
<insert id="testInsert">
INSERT INTO fruits (name, category, price) VALUES (#{name},#{category},#{price})
<if test="'__need_returning_id__' in params">
RETURNING id
</if>
</insert>
<delete id="testDelete">
DELETE FROM fruits WHERE id=#{id}
</delete>
<update id="testUpdate">
UPDATE fruits SET name=#{name} WHERE id=#{id}
</update>
</mapper>Write python code as follows:
from mybatis import MapperManager
mm = MapperManager()
mm.read_mapper_xml_file("mapper/test_namespace.xml")
sql, param_list = mm.insert("test_namespace.testInsert", {'name': 'Alice', 'category': 'A', 'price': 100})
assert sql == "INSERT INTO fruits (name, category, price) VALUES (?,?,?)"#{} is a placeholder that exists for prepared statement and will become the character '?' after processing by MapperManager. ${} represents simple string replacement. The following example illustrates the difference:
from mybatis import *
mm = MapperManager()
'''
The contents of test.xml are as follows:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper>
<select id="testStringReplace">
SELECT * from fruits_${date} where id=#{id}
</select>
</mapper>
'''
mm.read_mapper_xml_file("mapper/test.xml")
sql, param_list = mm.select("testStringReplace", {'id':1, 'date':"20241204"})
print(sql, param_list)The result is as follows:
SELECT * from fruits_20241204 where id=? [1]You can see that ${date} is replaced with "20241204", and #{id} is replaced with '?', and only one parameter value in param_list is 1.
Based on security considerations, in order to prevent SQL injection, it is recommended not to use ${} as long as #{} can be used, unless you are confident enough.
mybatis-py maintains a cache pool for each connection. The elimination strategy is LRU. You can define the maximum byte capacity of the pool. If you do not want to use cache, you can set the parameter configuration. The code is as follows:
from mybatis import *
def main():
conn1 = ConnectionFactory.get_connection(
dbms_name='mysql', # change to 'postgresql' if you are using PostgreSQL
host="localhost",
user="mybatis",
password="mybatis",
database="mybatis")
conn2 = ConnectionFactory.get_connection(
dbms_name='mysql', # change to 'postgresql' if you are using PostgreSQL
host="localhost",
user="mybatis",
password="mybatis",
database="mybatis")
mb1 = Mybatis(conn1, "mapper", cache_memory_limit=50*1024*1024) # Capacity limit is 50MB
mb2 = Mybatis(conn2, "mapper", cache_memory_limit=None) # Disable cachingIn order to prevent users from always getting old data, the cache will determine whether the key-value has expired when fetching a key-value. The maximum life milliseconds of the key-value can be specified through the cache_max_live_ms parameter in the constructor of the Mybatis class.
from flask import Flask
import mybatis.errors
from mybatis import Mybatis, ConnectionFactory
import orjson as json
import functools
app = Flask(__name__)
# 连接到 MySQL 数据库
conn = None
mb = Mybatis(conn, "mapper", cache_memory_limit=50*1024*1024)
connection_error = False
error_string = ""
def make_connection_and_mybatis():
global conn
global mb
global connection_error
global error_string
if conn is None:
try:
conn = ConnectionFactory.get_connection(
dbms_name="postgresql",
host="localhost",
user="mybatis",
password="mybatis",
database="mybatis"
)
mb.conn = conn
mb.conn.set_autocommit(False)
return True
except Exception as e:
connection_error = True
error_string = str(e)
return False
else:
try:
if connection_error:
conn.reconnect(3, 3)
connection_error = False
if mb.conn is None:
mb.conn = conn
return True
except Exception as e:
connection_error = True
error_string = str(e)
return False
@mb.SelectOne("SELECT * FROM fruits WHERE id=#{id}")
def select_one(id:int):
pass
@mb.SelectMany("SELECT * FROM fruits")
def select_many():
pass
@mb.Insert("INSERT INTO fruits (name,category,price) VALUES ('Candy', 'C', 500)")
def insert():
pass
def sql_auto_reconnect(func):
@functools.wraps(func)
def wrapper(*args, **kwargs):
global connection_error
try:
ret = make_connection_and_mybatis()
if ret is False:
return error_string, 500
ret = func(*args, **kwargs)
return ret, 200
except mybatis.errors.DatabaseError as e:
connection_error = True
return str(e), 500
except Exception as e:
return str(e), 500
return wrapper
@app.route('/')
@sql_auto_reconnect
def hello():
ret = select_many()
return json.dumps(ret)
@app.route('/insert')
@sql_auto_reconnect
def do_insert():
ret = insert()
return json.dumps(ret)
if __name__ == "__main__":
app.run(debug=True)