app.py
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
db = SQLAlchemy()
Session = db.sessionmaker(bind=db.engine)
session = Session()
db_session.py
from init import db
def fetch_to_dict(sql, params={}, fecth='all', bind=None):
'''
dict的方式返回数据
:param sql: select * from xxx where name=:name
:param params:{'name':'zhangsan'}
:param fecth:默认返回全部数据，返回格式为[{},{}],如果fecth='one',返回单条数据，格式为dict
:param bind:连接的数据，默认取配置的SQLALCHEMY_DATABASE_URL，
:return:
'''
resultProxy = db.session.execute(sql, params, bind=db.get_engine(bind=bind))
if fecth == 'one':
result_tuple = resultProxy.fetchone()
if result_tuple:
result = dict(zip(resultProxy.keys(), list(result_tuple)))
else:
return None
else:
result_tuple_list = resultProxy.fetchall()
if result_tuple_list:
result = []
keys = resultProxy.keys()
for row in result_tuple_list:
result_row = dict(zip(keys, row))
result.append(result_row)
else:
return None
return result
#记录条数
def get_count(sql, params={}, bind=None):
return int(fetch_to_dict(sql, params, fecth='one', bind=bind).get('count'))
# 分页
def fetch_to_dict_pagetion(sql, params={}, page=1, page_size=15, bind=None):
sql_count = """select count(*) as count from (%s) _count""" % sql
total_count = get_count(sql_count, params, bind=bind)
sql_page = '%s limit %s,%s' % (sql, (page - 1) * page_size, page_size)
print('sql_page:', sql_page)
result = fetch_to_dict(sql_page, params, 'all', bind=bind)
result_dict = {'results': result, 'count': total_count}
return result_dict
# 执行单条语句（update,insert）
def execute(sql, params={}, bind=None):
print('sql', sql)
db.session.execute(sql, params, bind=db.get_engine(bind=bind))
db.session.commit()
def get_count(sql, params={}, bind=None):
return int(fetch_to_dict(sql, params, fecth='one', bind=bind).get('count'))
# 执行多条语句，失败自动回滚
def execute_many(sqls):
print(sqls)
if not isinstance(sqls, (list, tuple)):
raise Exception('type of the parameters must be list or tuple')
if len(sqls) == 0:
raise Exception("parameters's length can't be 0")
for statement in sqls:
if not isinstance(statement, dict):
raise Exception("parameters erro")
try:
for s in sqls:
db.session.execute(s.get('sql'), s.get('params'), bind=db.get_engine(bind=s.get('bind', None)))
db.session.commit()
except Exception as e:
db.session.rollback()
raise Exception("execute sql fail ,is rollback")