sqlalchemy select

Recently, a third-party called API has been developed for a self-developed software platform. If the returned result set is in JSON format, it is easier to develop it in other languages, I found a lot of information on the Internet and didn't find it very suitable. Finally, I decided to change my mind to write a general one based on the information on the Internet. The main application scenario of this method is to convert the query results of the python database framework

Getting started with the SQLAlchemy framework of Python This article mainly introduces how to use the SQLAlchemy framework of Python. The SQLAlchemy framework is one of the ORM frameworks used to operate databases in Python. For more information, see A database table is a two-dimensional table that contains multiple rows and multiple columns. If the content of a

Yesterday briefly introduced the use of SQLAlchemy, but did not involve its most exciting ORM part, today I will briefly explain, of course, mainly to explain the contents of official documents, because it is a learning note, there may be a simplification or self-understanding of the part, do not do authoritative basis. When we start using ORM, a configurable structure can be used to describe our database tables, and the classes we define later will

Yesterday briefly introduced the use of SQLAlchemy, but did not be able to relate to its most exciting ORM part, today I will briefly explain, of course, mainly to explain the content of the official document, because it is learning notes, there may be a simplification or understanding of the part, do not do authoritative basis. When we start using ORM, a configurable structure can be used to describe our database tables, and the classes we define la

recommended) Authorization database All privileges except grant all permissions select only Check permissions Select,insert check and insert Permissions ... usage no access permission alter Use alter TABLEALTER routine with ALTER procedure and drop procedurecreate using create Tablecreate rout Ine use create procedurecreate temporary tables using create temporary tablescreate user using crea

Label:A. Count () in SQLAlchemyCOUNT () Statistics are particularly slow:Session.query (CLS). Count () 8W data cost nearly 50sHowever, query directly in the database: SELECT COUNT (*) from TABLE_NAME. Spents only 0.738sThis difference makes people really strange.Later in "1" saw the reason: The count() method is used to determine how many rows are returned in the result set, let us look at the resulting SQL statement,

*from User;Res_all =session.query (User). All ()Print(Res_all)#Select *from user where user_name= ' panda ';Res_panda = Session.query (User). Filter_by (user_name='Panda'). All ()Print(Res_panda)#Select *from user where user_name= ' panda ';res = Session.query (User). Filter (User.user_name = ='Panda'). All ()Print(RES)The result of the operation is as follows, the format returned here is defined as the __

) server_ Id=column (Integer,foreignkey (' server.id ')) group_id= Column (Integer,foreignkey (' GroUp.id ') Classgroup (Base):__tablename__= ' Group ' id=column (integer,primary_key=true) name=column ( String (unique=true,nullable=false), Classserver (Base): __tablename_ _= ' server ' id=column (integer,primary_key=true, Autoincrement=true) hostname=column (String),unique=true, Nullable=false) port=column (integer,default=22) Base.metadata.create_ All (engine) #base.metadata.drop_all (engine)

Exception handling: # exception One: attributeerror, object attribute does not exist Withengine.connect () asconn: Trans=conn.begin () s=select ([users]) try : r=conn.execute (s) forrecordinr: printrecord. passwordexceptattributeerror,e: print ' founderrors:{0} '. Format (e) Trans.rollback () # exception two: integrityerror, UNIQUE constraint error withengine.connect () asconn: trans=conn.begin () ins=users.insert (). VALUES ( id=2,customEr_nu

#Get Database fromSQLAlchemyImportCreate_enginedb= Create_engine ("sqlite:///:memory:", echo=True)#Create a tableDb.execute ("""CREATE TABLE Users (userid char (), username char ())""")#Inserting RecordsResultproxy = Db.execute ("""INSERT into users (userid,username) VALUES (' User1 ', ' Tony ')""") Resultproxy.rowcount#return rows affected by an UPDATE or DELETE statement#EnquiryResultproxy = Db.execute ("""SELECT * from Users""") Resultproxy.rowcoun

Flask-sqlalchemy is fun to use, easy to use for basic applications, and easy to scale for large projects. For a complete guide, see the API documentation for SQLAlchemy.In a common case where there is only one Flask application, all we need to do is create the Flask app, choose the load configuration and then create the SQLAlchemy object to pass the Flask app to it as a parameter.Once created, this object c

])) ## # #多条件查询 3 ways #Juxtaposition conditions #list = Session.query (Users). Filter (Users.name = = ' xx ', users.id>1) ##and_方法 #list = Session.query (Users). Filter (And_ (users.name = = ' xx ', users.id>1)) ## #多个filter #list =session.query (Users). Filter (Users.name = = ' xx '). Filter (users.id>1) ## # #单一条件并列or_ #list = Session.query (Users). Filter (or_ (users.name = = ' xx ', users.extra== ' KK ')) ## # #执行原生sql #list = Session.execute ('

__name__=="__main__": inInsert (User)4. Query datasql_select.py1 #Coding:utf-82 3 fromSqlalchemy.ormImportSessionmaker4 fromSQLAlchemyImportCreate_engine5 fromModelsImport*6 7 defSELECT (table_name):8Engine = Create_engine ("Mysql+mysqldb://root:[email protected]:3306/test")9 Print "initializing the Database engine"Ten OneDbsession = Sessionmaker (bind=engine) ASession =dbsession () - Print "Create Session Object" - theTable_data =session.query (User). All () - Print "Enquiry"

Tags: name error LTE expression Language RAM nbsp String filter InstallationIntroducedSQLAlchemy is an ORM framework based on Python implementations. The framework is built on the DB API, using relational object mappings for database operations, in short: converting Classes and objects to SQL, and then using the data API to execute SQL and get execution results.RoleHelp us quickly implement database operations using classes and objects.InstallationPIP3 Install

I recently used flask to develop a website. I cloned a small example from GitHub and used PostgreSQL as the database. When the database service is not opened, the following error is reported (): Traceback (most recent call last ): File "/root/workspace_aptana/flask-Bootstrap/APP. py", line 86, in DB. create_all ()File "/usr/lib/python2.6/Site-packages/flask_sqlalchemy.py", line 822, in create_allSelf. _ execute_for_all_tables (app, bind, 'create _ all ')File "/usr/lib/python2.6/Site-packages/fl

] ',... ' Phone ': 12345678901,... ' Password ': ' Www.111cn.net '... },... {... ' user_id ': 2,... ' username ': ' U2 ',... ' email_address ': ' [email protected] ',... ' Phone ': 12345678901,... ' Password ': ' Www.111cn.net '... }... ]>>> result = Connection.Execute (INS, multi_data)>>> Result.rowcount2 10. Enquiry >>> from SQLAlchemy importselect >>> s = select ([users]) >>> Print STR (s)

This article details the pythonorm framework SQLAlchemy simple application (database operations) instance code This article details the python orm framework SQLAlchemy simple application (database operations) instance code # _ * _ Coding: UTF-8 _ * _ ''' basic process for creating a SQLAlchemy Application 1. create a connection (create a connection with a relati

Python SqlAlchemy dynamically adds data table field instance parsing, pythonsqlalchemy This article mainly studies how to dynamically add data table fields in Python SqlAlchemy, as follows. We know that SqlAlchemy is used to create a class to map data tables. The class attribute is equal to the database field. However, when we create a table, we are not sure abou

Reference Python core programmingORM (Object relational Mapper), if you are a programmer who prefers to manipulate Python objects rather than SQL queries, and still want to use a relational database as your backend, you might prefer to use ORM.ORM takes a pure SQL statement and implements it as an object in Python, so that you manipulate these objects just as you would with SQL statements--tables in a database are converted to Python classes, where data columns are attributes, and database opera

Using the Flask framework to link 2 types of databases----------db.py#-*-coding:utf-8-*-#Flask Hello World fromFlaskImportFlask fromFlask.ext.mysqlImportMysqlapp= Flask (__name__)" "' # # #链接数据库MySQL版mysql = MySQL () app.config[' mysql_database_user ') = ' root ' app.config[' mysql_database_password '] = ' Root ' app.config[' mysql_database_db ' = ' test ' app.config[' mysql_database_host '] = ' localhost ' mysql.init_app (APP) cursor = Mysql.connect (). Cursor () if __name__ = = ' __main__ ': C