SQLAlchemy Tutorial-The second chapter-sql the ORM of common queries

Today is 2018-07-02.
Write the ORM notation for common SQL queries today.

1. The EMP, which is the model of the employee table, is first mended.

class Emp(Base):    __tablename__ = ‘emp‘    empno = Column(Integer, primary_key=True)    ename = Column(String(10))    job = Column(String(9))    mgr = Column(Integer)    hiredate = Column(Date)    comm = Column(DECIMAL(7, 2))    deptno = Column(Integer, ForeignKey(‘dept.deptno‘))    def __repr__(self):  # 定义这个方法是为了方便打印到控制台查看.        return str({            ‘empno‘: self.empno,            ‘ename‘: self.ename,            ‘job‘: self.job,            ‘deptno‘: self.deptno        })

1. Next, let's make some basic queries.

from models import *def query_emp():    emp1 = sess.query(Emp).first()    print(emp1)# 查询名字叫Smith的员工def query_emp_with_filter():    emp1 = sess.query(Emp).filter(Emp.ename == ‘Smith‘).first()    print(emp1)# 查询名字叫Smith, 职务为CLERK的一个员工def query_emp_with_filters():    emp1 = sess.query(Emp).filter(Emp.ename == ‘Smith‘, Emp.job == ‘CLERK‘).first()    print(emp1)# 查询职务为CLERK的全部员工def query_emp_all_clerks():    emp_clerks = sess.query(Emp).filter(Emp.job == ‘CLERK‘).all()    for clerk in emp_clerks:        print(clerk)# 查询员工的名字和工号, 并按入职日期排序def query_emp_empno_ename_order_by_hiredate():    emps = sess.query(Emp.empno, Emp.ename, Emp.job, Emp.hiredate).order_by(Emp.hiredate.asc()).all()    for item in emps:        print(item.empno, item.ename, item.job, item.hiredate)if __name__ == ‘__main__‘:    query_emp_empno_ename_order_by_hiredate()

Today is limited to time, first so much. The explanation is very poor, the classmate has the question, please leave a message.

SQLAlchemy official website
Http://docs.sqlalchemy.org/en/latest/contents.html
Tutorials All code GitHub address
Https://github.com/notfresh/sqlalchemy_demo

SQLAlchemy Tutorial-The second chapter-sql the ORM of common queries