- SQLAlchemy版本信息检查
- 数据库链接
- 创建engine
- 数据库URL支持
- Postgresql:
- MySQL:
- Oracl:
engine = create_engine(‘oracle://scott:tiger@127.0.0.1:1521/sidname‘)engine = create_engine(‘oracle+cx_oracle://scott:tiger@tnsname‘)
- Microsoft SQL Server:
# pyodbcengine = create_engine(‘mssql+pyodbc://scott:tiger@mydsn‘)# pymssqlengine = create_engine(‘mssql+pymssql://scott:tiger@hostname:port/dbname‘)
- SQLite:
#Unix/Mac - 4 initial slashes in totalengine = create_engine(‘sqlite:////absolute/path/to/foo.db‘)#Windowsengine = create_engine(‘sqlite:///C:\\path\\to\\foo.db‘)#Windows alternative using raw stringengine = create_engine(r‘sqlite:///C:\path\to\foo.db‘)#Memony SQLite databaseengine = create_engine(‘sqlite://‘)
- Declarative方法对象
- 基类创建
- 基于基类创建映射类
- 通过映射类创建实例
user = User(name=‘Huangy‘,fullname=‘Huangya‘, password=‘123.com‘)
- Session，用于ORM与数据库的链接，创建session的时候需绑定数据库engine
- 需要session时，再初始化
- 虽然以上操作session和engine已经关联，但是无任何链接，当使用的时候，再从engine维护的链接池中检索是否存在链接，若存在则保持，直到close或更改。
import sqlalchemyprint(sqlalchemy.__version__)
from sqlalchemy import create_engineengin=create_engine("dialect+driver://username:password@host:port/database")# defaultengine = create_engine(‘postgresql://scott:tiger@localhost/mydatabase‘)# psycopg2engine = create_engine(‘postgresql+psycopg2://scott:tiger@localhost/mydatabase‘)# pg8000engine = create_engine(‘postgresql+pg8000://scott:tiger@localhost/mydatabase‘)
# defaultengine = create_engine(‘mysql://scott:tiger@localhost/foo‘)# mysql-pythonengine = create_engine(‘mysql+mysqldb://scott:tiger@localhost/foo‘)# MySQL-connector-pythonengine = create_engine(‘mysql+mysqlconnector://scott:tiger@localhost/foo‘)# OurSQLengine = create_engine(‘mysql+oursql://scott:tiger@localhost/foo‘)
from sqlalchemy.ext.declarative import declarative_baseBase = declarative_base()
from sqlalchemy import Column,Integer,Stringclass User(Base): ???__tablename__="user" ???id=Column(Integer,primary_key=True) ???name=Column(String)
from sqlalchemy.orm import sessionmakerSession=sessionmaker(bind=engine)
#当需要和数据库链接的时候，再初始化一个session对象session=Session()
20180202之engine,URL,base,session
原文地址：https://www.cnblogs.com/yaya625202/p/8406522.html