Tags: join mysq form Base Content Select column Delete PostMultithreaded Example Import time
import threading from
sqlalchemy.ext.declarative import declarative_base from
SQLAlchemy Import Column, Integer, String, ForeignKey, UniqueConstraint, Index from
sqlalchemy.orm import Sessionmaker, Relationship from
sqlalchemy import create_engine from
DB import Users
e
Python sqlalchemy module (required in the project) and pythonsqlalchemySqlalchemy Introduction
SQLAlchemy is an open-source software in the Python programming language. Provides the SQL Toolkit and object relationship ing (ORM) tool, which can be issued using the MIT license.
SQLAlchemy "uses a simple Python language, designed for efficient and high-performance d
Tags: database connection statement foreign lang. com SQL Date commit setFirst, Introduction SQLAlchemy is an ORM (object-relational Mapping) framework used to map a relational database to an object. The framework builds on the DB API, transforms classes and objects into SQL, and then executes the SQL using the API and obtains the execution results.Second, the composition
Schema/types, architecture and type
SQL exprression language,sql
Flask ==> Orm sqlalchemy1. What is ORMORM, the Object-relational Mapping (Object relational mapping), is a mapping between a relational database and a business entity object,In this way, we do not need to deal with complex SQL statements when we operate the business objects, simply manipulate the object's properties and methods.What is 2.SQLALchemy?SQLAlchemy is an ORM framework based on Python implementati
executed directly from the second phase, we can only execute pure SQL statements with SQLAlchemy, the code is as follows:From SQLAlchemy import Create_engine#1, prepare#需要事先安装好pymysql#需要事先创建好数据库: Create Database db1 charset UTF8;#2, creating enginesEgine=create_engine (' Mysql+pymysql://[email Protected]/db1?charset=utf8 ')#3, Execute SQLEgine.execute (' CREATE table if not ' EXISTS t1 (id int PRIMARY KEY
, complex query statements, relying on simple ORM is more difficult to achieve.Actual Connection DatabaseFirst you need to import the SQLAlchemy library and then establish a database connection, which is used here mysql . by create_engine means of from sqlalchemy import create_engine
engine = create_engine("mysql://root:@localhost:3306/webpy?charset=utf8",encoding="utf-8", echo=True) create_enginemethod to
:
engine=create_engine("mssql+pyodbc://sa:@192.168.6.112:1433/FactoryHome?driver=SQL+Server+Native+Client+10.0")
Another method is to connect through Microsoft's dsn. If you do not know the dsn connection, you can Baidu to see what it means.
Insert data
From sqlalchemy import * engine = create_engine ("mssql + pyodbc: // sa: @ 192.168.6.112: 1433/FactoryHome? Driver = SQL + Server + Native + Client + 10.0 ") metadata = MetaData () Table_1 = Table (" T
decides when to execute the SQL statement. Mysql_session_maker = Sessionmaker (bind=engine) Session=Mysql_session_maker ()" "# Once you get the session, you can execute SQL session.execute (' CREATE DATABASE abc ') Print (Session.execute (' Show Databases '). Fe Tchall ()) Session.execute (' use ABC ') # The process of building the user table is slightly print session.execute (' select * from user where id = 1 '). f Irst () Print Session.execute ('
; session.query (User). Filter (User.name.like ('%ed ')). Count ()
SELECT count (*) as count_1 from
( SELECT users.id as users_id,
users.name as Users_name,
users.fullname as Users_fullname,
Users.password as Users_password from the
users
WHERE users.name like? As Anon_1
('%ed ',)
2
The count () method is used to determine how many rows are in the returned result set, let's
First, Sqlalchemy-utilsBecause the choice method is not available in SQLAlchemy, the choice method provided by the Sqlalchemy-utils componentImportdatetime fromSQLAlchemyImportCreate_engine fromSqlalchemy.ext.declarativeImportDeclarative_base fromSQLAlchemyImportColumn, Integer, String, Text, ForeignKey, DateTime, UniqueConstraint, Index fromSqlalchemy.ormImportR
fromSqlalchemy.ext.declarativeImportDeclarative_base#to create a base class for an object:Base =declarative_base ()#Define a User object: You can define multiple classes
classUser (Base):#Name of the table:
__tablename__='User'
#Structure of the table:id = Column (Integer, primary_key=True) name= Column (String (20))
# To initialize a database connection:
Engine = Create_engine ('mysql+mysqlconnector://root:yourpassword@ localhost:3306/test') # connection information: ' Databas
This article mainly introduces the data query instance of the PythonORM framework SQLAlchemy learning notes. if you need it, you can refer to the preparation work we have done in the early stage. now this is one of the key content to query, of course, the previous article involves more or less queries. for example, a Query object is obtained through the query () method of the Session, note that the number of parameters in this method is variable. that
objects, object properties, or similar operations at this time, SQLAlchemy will give you the data you want to query after executing the SQL statement.
To better illustrate this, here's an example of our first query example, we called the query object to help us do this, like here we get the user Ed who just persisted, and we use "Filter by" to query the user named Ed, Of course we only need an ED, if there are multiple Ed with the same name, the que
", Echo, module"
#address database://username: password (null without password) @ Host name: Port/Database name
# The Echo ID is used to set up the SQLAlchemy log system completed through the Python standard log module, and when logging is turned on, we will be able to see all the SQL generated code
# 3. Establish a connection
connection = Mysql_ Engine.connect ()
# 4. Query table information Result
= Connection.Execute ("
Reply content:The Django model driver pays little attention to the implementation details at the database level, and the process of defining the models is very close to declarative rather than procedural, which may be the reason for the new project to make Django model more pleasing than SQLAlchemy.
The traditional use of SQLAlchemy is not to invade the model, in a separate place to define the table struct
Tags: support mysql OTT 127.0.0.1 upgrade database std CharFlask-sqlalchemy Installation and Setup
SQLALchemy is actually an abstraction of the database, so that developers do not have to deal with SQL statements directly, but through the Python object to manipulate the database, while discarding some performance overhead, in exchange for the development efficiency of a large increase
Tags: mic str difference view string Gone app statement null valueORM(Object relational Mapper) objects relational mappings.Refers to a relationship object that maps the method that faces the object to a database. Flask-sqlalchemy is a Flask extension, able to support a variety of database background, we can not need to care about SQL processing details, operations database, a basic relationship corresponding to a class, and an entity corresponding to
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