Schema

在阅读 What are the general differences between a format and a protocol 时，其中有使用schema这个词语，这让我想起了database scheme，所以决定对schema这个词语进行深入分析、总结。下面是对它的直观感受:

它所描述的是abstract structure，一个典型的例子是: database table是抽象的structure，它和entity都是对具体的抽象。

What is schema

stanford Stanford Encyclopedia of Philosophy # Schema

NOTE: 这篇文章对schema的解释是非常好的

wikipedia Schema

In psychology and cognitive science, a scheme (plural(复数) schemata or schemes) describes a pattern of thought or behavior that organizes categories of information and the relationships among them. Schemes have frequently been mistranslated from the original French as 'Schema' It can also be described as a mental structure of preconceived(预想) ideas, a framework representing some aspect of the world, or a system of organizing and perceiving new information. Schemata influence attention and the absorption(吸收) of new knowledge: people are more likely to notice things that fit into their schema, while re-interpreting contradictions to the schema as exceptions or distorting them to fit. Schemata have a tendency to remain unchanged, even in the face of contradictory information. Schemata can help in understanding the world and the rapidly changing environment. People can organize new perceptions(观念) into schemata quickly as most situations do not require complex thought when using schema, since automatic thought is all that is required.

Schema and format

在What are the general differences between a format and a protocol的第二个回答中，有这样的描述:A format describes the structure of some data这提示了我，format也是一种schema。下面就有xml schema、json schema等等。在文章medium Use Binary Encoding Instead of JSON 中，就反复使用了schema这个术语。

XML schema

http://en.wikipedia.org/wiki/XML_schemahttps://www.w3schools.com/xml/schema_intro.asp

JSON Schema

https://json-schema.org/

Database schema

https://en.wikipedia.org/wiki/Database_schema

Axiom schema

参见Mathematical-logic中的Axiom Schema章节。