Django之ORM Django之ORM Object Relational Mapping(ORM) ORM介绍 ORM概念 对象关系映射(Object Relational Mapping,简称ORM)模式是一种为了解决面向对象与关系数据库存在的互不匹配的现象的技术。 简单的说,ORM是通过使用描述对象和数据库之间映射的元数据,将程序中的对象自动持久化到关系数据库中。 ORM在业务逻辑...
https://www.pythoncentral.io/sqlalchemy-vs-orms/#:~:text=%20Comparison%20Between%20Python%20ORMs%20%201%20SQLObject.,the%20unit-of-work%20concept%20which%20is%20prevalent...%20More%20 Django's ORM Pros: Easy-to-use with a short learning curve Tightly integrated with Django to make it...
AdvancedConcept3.md AdvancedConcepts.md Authentication.md Authentication0.md Authentication1.md Authentication2.md ClassBasedViews0.md ClassBasedViews1.md ClassBasedViews2.md ClassBasedViews3.md ClassBasedViews4.md Deployment.md DjangoORM.md DjangoORM0.md DjangoORM1.md DjangoORM2.md DjangoORM3.md...
generic_fk.py- Illustrates a so-called "generic foreign key", in a similar fashion to that of popular frameworks such as Django, ROR, etc. This approach bypasses standard referential integrity practices, in that the "foreign key" column is not actually constrained to refer to any particular t...
Central to the ability to undelete a soft-deleted model is the concept of changesets. When you soft-delete an object, any objects referencing it via a ForeignKey, ManyToManyField, or OneToOneField will also be soft-deleted. This mimics the traditional CASCADE behavior of a SQL DELETE. ...
In the above query both joins are LEFT OUTER, since a user may not have any tweets or, if they have tweets, none of them may have been favorited.Peewee has a concept of a join context, meaning that whenever we call the join() method, we are implicitly joining on the previously-join...
Make autodiscover of models based on this apps concept. Implement basic migration tool so users will stay within scope of ORM. I think it should look like system where user can manually create migration which will consist offorwardandbackwardmethods, where user can write pure SQL and write some...
Now if tables was not found in input DDL - models generator raise NoTable error. if you want to have still silent exit if no tables, please use flag: exit_silent v0.8.3 Added fundamental concept of TableMetaModel - class that unifies metadata parsed from different classes/ORM models types...
Document app concept Document Filters Document Aggregate Functions (#3) Complete Testing: Test Q (filter, not-Q, bad-Q) Test values() & values_list() (with relation, multi-key) Test sorting/filtering of M2M relation Done Add BinaryField type Fields Schema generation refactoring (#97, #206...
Abstract:In the process of carrying out system application development using Python,the URUD operations on various types of relational database,such as MySQL,Oracle,SQL Server and so on,needs to base on the concept and model of ORM framework specification. Therefore,it is of great practical valu...