- 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:
# pyodbc engine = create_engine(‘mssql+pyodbc://scott:tiger@mydsn‘) # pymssql engine = create_engine(‘mssql+pymssql://scott:tiger@hostname:port/dbname‘)
- SQLite:
#Unix/Mac - 4 initial slashes in total engine = create_engine(‘sqlite:////absolute/path/to/foo.db‘) #Windows engine = create_engine(‘sqlite:///C:\\path\\to\\foo.db‘) #Windows alternative using raw string engine = create_engine(r‘sqlite:///C:\path\to\foo.db‘) #Memony SQLite database engine = 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 sqlalchemy print(sqlalchemy.__version__)
from sqlalchemy import create_engine engin=create_engine("dialect+driver://username:password@host:port/database")
# default engine = create_engine(‘postgresql://scott:tiger@localhost/mydatabase‘) # psycopg2 engine = create_engine(‘postgresql+psycopg2://scott:tiger@localhost/mydatabase‘) # pg8000 engine = create_engine(‘postgresql+pg8000://scott:tiger@localhost/mydatabase‘)
# default engine = create_engine(‘mysql://scott:tiger@localhost/foo‘) # mysql-python engine = create_engine(‘mysql+mysqldb://scott:tiger@localhost/foo‘) # MySQL-connector-python engine = create_engine(‘mysql+mysqlconnector://scott:tiger@localhost/foo‘) # OurSQL engine = create_engine(‘mysql+oursql://scott:tiger@localhost/foo‘)
from sqlalchemy.ext.declarative import declarative_base Base = declarative_base()
from sqlalchemy import Column,Integer,String class User(Base): __tablename__="user" id=Column(Integer,primary_key=True) name=Column(String)
from sqlalchemy.orm import sessionmaker Session=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()
