《Django 5 By Example》学习第 19 天,p543-p550 总结,总计 8 页。
一、技术总结
1.fixtures
(1)定义
A fixture is a collection of files that contain the serialized contents of the database.
(2)作用
1)数据导入
一般来说,我们是通过数据库工具(如:Navicat,DBeaver)进行数据导入和导出。在 Django中,也可以通过 fixtures 结合 duamdata 、loaddata 命令进行数据导入导出。
单纯从数据导入导出这点来说,我更倾向于使用数据库工具进行操作,因为这更通用。
(3)示例
注:educa是 project, courses 是 application。
educa# mkdir courses/fixture
educa# python manage.py dumpdata courses --indent=2 --output=courses/fixtures/subjects.json
educa# python manage.py loaddata subjects.json
2.model inheritance
Django中有三种类型 model inheritance:
(1)abstract model
(2)multi-table model inheritance
(3)proxy model
二、英语总结(生词:2)
1.polymorphism
(1)polymorph
poly-("many") + morph("form, shape")
(2)polymorphism: polymorph + -ism
u. the fact the sth can exist in different forms(多态性)。
(3)polymorphous vs polymorphic
adj. having many different forms(多态的)。polymorphous 和 polymorphic的意思是一样的,他们之间的区别是:
1)polymorphous
Commonly used as a descriptive term in general contexts, including art, literature, and natural sciences.
示例:Water is a polymorphous substance, taking the form of ice, liquid, or vapor.
2)polymorphic
Often used in technical or scientific contexts, such as programming, biology, or chemistry.
示例:The class exhibits polymorphic behavior by overriding methods in different subclasses.
2.provision
(1)provision: pro-("before, forward") + vision(from videre, "to see")
字面意思是“to see beforehand(预先看看)”, “to prepare in advance(提前准备)”,后面演变为:c/u. the act of providing sth。
(2)provide: provision 是 provide 的名词形式。
p546, Polymorphism is the provision of a single interface to entities of different types(多态是为不同类型的实体提供单一接口).
三、其它
今天没有什么想说的。
四、参考资料
1. 编程
(1) Antonio Melé,《Django 5 By Example》:https://book.douban.com/subject/37007362/
2. 英语
(1) Etymology Dictionary:https://www.etymonline.com
(2) Cambridge Dictionary:https://dictionary.cambridge.org
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