Structured data, also known as row data, is data that is logically expressed and realized by a two-dimensional table structure, strictly follows the data format and length specifications, and is mainly stored and managed through a relational database. Structured data tagging is a way to make a website better displayed in search results. By marking the structured data, the website can display rich web abstracts in the search results.

unstructured data is data whose data structure is irregular or incomplete, and there is no predefined data model, so it is not convenient to express it with a two-dimensional logical table of the database. Unstructured data has a variety of formats and standards, and unstructured information is technically more difficult to standardize and understand than structured information.

Semi-structured data has certain structure and is a data model suitable for database integration. That is to say, it is suitable for describing data contained in two or more databases (which contain similar data in different patterns). It is also a basic model of tagging service, which is used to enjoy information on the Web.

Extended data:

Marking methods of structured data

1. There are three main ways to mark p>HTML codes: microdata, microformat and RDFa. However, for some foreign trade stations, the tags are mainly micro-data, and microformats are sometimes used, depending on the type of pages that are not used.

2. Use microdata tags

If microdata tags are used, the mainstream is to use schema for tagging. However, because there are some items on the page, the schema does not introduce the corresponding markup code, so it is still necessary to use data-vocal to mark them, so that the old and new codes will coexist in the page code.

Baidu encyclopedia-structured data

Baidu encyclopedia-unstructured data

Baidu encyclopedia-semi-structured data.