ORM(Object Relational mapping): Object Relational mapping .Python is object -oriented, and the database is relational .ORM is the mapping of database relationships to objects in Python, without the need to write directly to SQL.The disadvantage is that performance is slightly worse .Through Sessionmaker, we get a class, a factory that can produce a session.For the purpose of using scoped_session, Word: for thread safety .Scoped_session is similar to singleton mode , when we call to use, we will
Tags: Open data null end use relationship ALC filter RAC1.engine = Create_engine (echo=true) SQLAlchemy commands that communicate with the database will print out12018-01-13 09:42:43,634 INFO sqlalchemy.engine.base.Engine show collation where ' Charset ' ='UTF8' and' Collation ' ='Utf8_bin'22018-01-13 09:42:43,634INFO sqlalchemy.engine.base.Engine {}32018-01-13 09:42:43,738 INFO sqlalchemy.engine.base.Engine SELECT CAST ('Test Plain returns'As CHAR (
- exceptevaluator. Unevaluatableerror: - RaiseSa_exc. Invalidrequesterror ( - "Could not evaluate current criteria in Python."
+ "specify ' fetch ' or False for the"
- "synchronize_session parameter.")
+
A #Todo:detect when the WHERE clause is a trivial primary key match
atSelf.matched_objects = [
-Obj for(CLS, PK), objinch
- Query.session.identity_map.items () - ifIssubclass (CLS, TARGET_CLS) and
all database connection conditions: Show full processlist;⑥.lsof-i: 3306 Viewing the port of the database [3306] now running the situationHowever, the follow-up still need to put Sqlachemy website recommended web How to use the session of the English to masturbate ... Http://docs.sqlalchemy.org/en/latest/orm/session_basics.html#session-faq-whentocreateThen there is a doubt, in the use of ⑥, there are some celery programs have been found to appear closewait state.The TCP connection has a 3-time
Copy CodeThe code is as follows:
def sa_obj_to_dict (obj, Filtrate=none, Rename=none):
"""
SQLAlchemy object to Dict
:p Aram filtrate: Filtered Fields
: Type filtrate:list or tuple
:p Aram Rename: Renaming is required, rename is processed after filtering, key is the property name of the original object, value is required to change the name
: Type Rename:dict
: rtype:dict
"""
If Isinstance (obj.__class__, Declarativemeta):# an
(User.Name = = None)
7. is not NULL
Copy CodeThe code is as follows:
Filter (User.Name! = None)
8. and
Copy CodeThe code is as follows:
From SQLAlchemy import And_
Filter (and_ (user.name = = ' ed ', user.fullname = = ' ed Jones '))
# or call filter ()/filter_by () multiple times
Fi
Studies the ing between SQLAlchemy databases in the Python ORM framework, ormsqlalchemy
We have introduced the User table about the User account, but in real life, with the complexity of the problem, the data stored in the database cannot be so simple. Let's imagine another table, this table is associated with the User and can be mapped and queried. Therefore, this table can store any number of email addresses associated with an account. This relation
bool
Boolean value
Date
Datetime.date
Time
Time
Datetime.datetime
Date and time
Largebinary
Str
binary files
Used insqlalchemy Relationship Options
Option name
Description
Primary_key
If true, represents the primary key for the table
Unique
If true, this column does not allow duplicate values
Index
Tags: rom function code mysq utf-8 drop key group left join# # Join:1. Join is divided into a left join (outer join) and Right join (outer connection) and an inner join (equivalent connection).2. Reference page: http://www.jb51.net/article/15386.htm3. In SQLAlchemy, use join to complete the inner join. When writing a join, if the join condition is not written, the default is to use the foreign key as the conditional connection.4. Query finds what valu
Tags: Eve cal bind nbsp ROR string Pytho address CEPFirst you need a module sshtunnel, if there is no direct pip install SshtunnelFrom Sshtunnel import sshtunnelforwarderfrom sqlalchemy import Column, String, Integer, Create_engine, Eventfrom Sqlalche My.orm Import sessionmakerfrom sqlalchemy.ext.declarative import declarative_basefrom sqlalchemy.exc Import Disconnectionerrorssh_host = "" # Fortress machine IP address or hostname ssh_port = 22 # The p
use a connection to make sure that the number of MySQL concurrencyconn = pymysql.connect(host=‘‘, port=, user=‘‘, passwd=‘‘, db=‘‘)cus = conn.curse()(2) Execute SQL"select * from Student;"cus.execute(sql)cus.fetchone() 获取单个 返回值 tuplecus.fetchall() 获取多个 返回值 list(单个元素是tuple)cus.fetchmany(size=n) 获取多个(3) Closing cursors and connectionscus.close()conn.close()Note the use of combined try exception finallyIi. Summary of sqlalchemy operation1. Creating an e
connection to make sure that the number of MySQL concurrencyconn = pymysql.connect(host=‘‘, port=, user=‘‘, passwd=‘‘, db=‘‘)cus = conn.curse()(2) Execute SQL"select * from Student;"cus.execute(sql)cus.fetchone() 获取单个 返回值 tuplecus.fetchall() 获取多个 返回值 list(单个元素是tuple)cus.fetchmany(size=n) 获取多个(3) Closing cursors and connectionscus.close()conn.close()Note the use of combined try exception finallyIi. Summary of sqlalchemy operation1. Creating an enginee
Tags: run trap bootstra sed style key ase Roo 127.0.0.1In the Flask project, establish a models.py in the configuration database as follows: 1 #-*-coding:utf-8-*-
2 ImportOS3 fromFlaskImportFlask4 fromItsdangerousImportTimedjsonwebsignatureserializer as Serializer5 fromFlaskImportCurrent_app6 from.ImportDB7 fromFlask_sqlalchemyImportSQLAlchemy8 fromWerkzeug.securityImportGenerate_password_hash, Check_password_hash9 fromFlask_loginImportusermixinTen fromFlask_loginImportlogin_required One
Tags: Clipboard python object ext problem top mil case blank aboutUsing SQLAlchemy can easily read the data from the Python object in the form of a database (spit slot: To tell the truth, the form of the object is not much convenient, as I have directly read from the relational database dict form of data to use it handy, see my previous article http:// ZHENGXIAOYAO0716.LOFTER.COM/POST/1D6E9C56_93D6D00))However, data in the form of objects is inconveni
Tags: format mysql entity test creat span entity class IV SEL1.sqlalchemy is an ORM framework and uses meta-programming extensively ImportSQLAlchemy fromSQLAlchemyImportCreate_engine fromSqlalchemy.ext.declarativeImportDeclarative_base fromSQLAlchemyImportcolumn,integer,date,string connect_string="{}://{}:{}@{}:{}/{}". Format ('Mysql+pymysql',
'Test',
'1QAZXSW2',
'127.0.0.1',
'3306',
'Blog') Engine= Create_engine (connect_string,ec
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.