Structured and unstructured data

Structured and unstructured data

Structured Data: Row data, which is stored in a database, can be logically expressed using a two-dimensional table structure.

 

Unstructured data: data that cannot be expressed using two-dimensional Logical tables of the database, including all formats of office documents, text, images, XML, HTML, various reports, images and audio/video information.

 

Semi-structured data: data between fully structured data (such as relational databases and data in object-oriented databases) and completely unstructured data (such as sound and image files, HTML documents are semi-structured data. It is generally self-describing, and the data structure and content are mixed together without obvious distinction.

 

Structured data types are user-defined data types that contain non-atomic elements. More specifically, they can be used separately, it can also be used as an independent unit as appropriate. This article will introduce you to the concept of structured data types, and show you how to create and use structured data types, type hierarchies, and typed tables by using some examples.

 

Structured Data is a user-defined data type. It contains a series of attributes, each of which has a data type. Attribute is used to help describe the characteristics of a type instance.

 

An unstructured database is a database with variable field lengths and records of each field can be composed of repeated or non-repeated child fields, it not only can process structured data (such as numbers and symbols), but also is more suitable for processing unstructured data (such as full text, images, sound, film and television, and hypermedia ).

 

Unstructured web databases are mainly generated for unstructured data. Compared with popular relational databases, the biggest difference is that it breaks through the constraints of changing the schema definition of a relational database and setting the Data Length, supports repeated fields, subfields, and variable-length fields, and enables processing of variable-length data and repeated fields, and variable-length storage and management of data items. It processes continuous information (including full-text information) unstructured information (including various multimedia information) has incomparable advantages of traditional relational databases.

 

 

With the development of network technology, especially the rapid development of Internet and Intranet technology, the number of unstructured data is increasing. At this time, the limitations of relational databases that are mainly used to manage structured data are becoming more and more obvious. Therefore, the database technology entered the "post-relational database era" and evolved into the era of unstructured databases based on network applications.