sqlalchemy select

(User.name.desc()).all()print(data) 　　3. modify data First assignment # data = Session.query(User).filter(User.name=='Marry').first()data = Session.query(User).filter_by(name='Marry').first()data.name = 'Tom'Session.commit() Second update Session.query(User).filter_by(name='Tom').update({'name': 'Hary'})Session.commit() Rollback Ession. query (User ). filter_by (name = 'hary '). update ({'name': 'john'}) print (Session. query (User ). filter_by (name = 'john '). all () # roll back the S

-07-18 23:57:28, 027 INFO sqlalchemy. engine. base. Engine select database ()2014-07-18 23:57:28, 032 INFO sqlalchemy. engine. base. Engine ()23:57:28, 034 INFO sqlalchemy. engine. base. Engine show collation where 'charset' = 'utf8' and 'colation' = 'utf8 _ bin'2014-07-18 23:57:28, 034 INFO

Tags: basic getting Started PythonBrief introduction:Description: This module is primarily used to map a relational database table to a class of py, the row maps to an instance of the Py class, and the column maps to the properties of the Py instance, because it is compatible with many Db-api and extension, so can prioritize the data model, while ignoring the underlying DB-API switch, data migration is more convenient.Quick installation: Pip Install--upgrade

SQLAlchemy问题记录Company Price quantitymicrosoft Google 99 5google 101 the to implement script Select as from where company='Google' GROUP by Price;SQLAlchemy notationYou actually need the label () method.result = Dbsession.query (shares.price, func.sum (shares.quantity). Label ("T

=new_person) sess Ion.add (new_address) Session.commit ()You can see the data directly from the database background:Mysql> SELECT * from person;+----+------------+| ID | Name |+----+------------+| 1 | New person |+----+------------+1 row in Set (0.00 sec) mysql> SELECT * from address;+----+-------------+--------------- +-----------+-----------+| ID | Street_name | Street_number | Post_code | person_i

statements by simply using ORM. PracticeConnect to databaseFirst, import the sqlalchemy database and establish a database connection. mysql is used here. Using the create_engine Method from sqlalchemy import create_engineengine = create_engine("mysql://root:@localhost:3306/webpy?charset=utf8",encoding="utf-8", echo=True) The create_engine method connects to the database and returns a db object. Parameter R

://code.google.com/p/pypyodbc/ ==============================#connnectionless执行和connnection执行==============================1. The way to execute SQL directly using engine is called connnectionless execution,2. Use Engine.connect () to get conn, then execute SQL via conn, called Connection executionIf you want to perform in transaction mode, it is recommended that you use the connection method, and if you do not involve transaction, the two methods are the same. ==============================#

is Python's DBAPI. It should be noted that at this time there is no substantial connection to the database. When will the connection be established with the database? This will only happen when you first query the database. Er... This is a bit like Lazy Loading (Lazy Loading, delayed Loading). That is to say, we need to actually create a connection when operating the database. SQLAlchemy uses Lazyload in many places and will be introduced later. Next

Tags: ret offset div Set SQL Elf like item stateQuery queries are used in SQLAlchemy, and basequery queries are used in Flask-sqlalchemy, and they are the relationships between subclasses and parent classesSuppose page_index=1,page_size=10; All paged queries cannot be followed by first (), all (), etc.1.sets the index offset with offset (), limit () limits the amount takenDb.session.query (User.Name). Filte

userBackref will add a relationship between user and address, which is essentially:From SQLAlchemy ImportInteger, ForeignKey,String,ColumnFrom sqlalchemy.ext.declarative import declarative_basefrom sqlalchemy.orm Import relationshipbase = Declarative_base ( ) class User (Base): __tablename__ =' user 'ID =Column(Integer, primary_key=True) name =Column(String) addresses = relationship ("Address", back_populates="User") class Address (Base): __tablename

Sqlalchemy _ getting started with sqlalchemyDatabase operation software, similar to pdo in php, is more flexible and complex than pdo. It can correspond the tables in the database to the classes in the program one by one for convenient calling. If the class can be written in the early stage, do not write SQL later; install pip install flask_sqlalchemy Create a table: 1 from flask_sqlalchemy import SQLAlchemy