What database language does sql belong to?

sql is a relational database language. Relational database language is a database language with multiple functions such as data manipulation and data definition. This language has interactive characteristics, can provide users with great convenience, and can use SQL language to improve the work quality and performance of computer application systems. efficiency.

SQL is a relational database language,

A relational database language with data manipulation and data definition It is a database language with multiple functions. This language has interactive characteristics and can provide users with great convenience. It can also use SQL language to improve the work quality and efficiency of computer application systems.

Features

1. Storage method: Traditional relational database uses table storage method, and data is stored in rows and columns. , it is very convenient to read and query.

2. Storage structure: Relational databases store data in a structured way. Each data table must define each field (that is, define the structure of the table first). Then the data is stored according to the structure of the table. The advantage of this is that the form and content of the data have been defined before the data is stored, so the reliability and stability of the entire data table are relatively high, but it brings problems That is, once the data is stored, it will be very difficult to modify the structure of the data table.

3, Storage specifications: In order to avoid duplication, standardize data and make full use of storage space, relational databases store data in the form of minimum relational tables, so that data management can It becomes very clear and obvious. Of course, this is mainly the case of a data table. The situation is different if there are multiple tables. Since the data involves multiple data tables, there are complex relationships between the data tables. As the number of data tables increases, data management will become more and more complex.

4, Extension method: Since relational databases store data in data tables, the bottleneck of data operations appears in the operation of multiple data tables, and the more data tables there are, the more this problem arises The more serious it is, if you want to alleviate this problem, you can only improve the processing power, that is, choose a computer with faster speed and higher performance. Although this method can expand the space to a certain extent, the expansion space must be very limited, that is, Relational databases only have vertical expansion capabilities.

5, Query method: Relational databases use structured query language (SQL) to query the database. SQL has long been supported by various database manufacturers and has become the standard in the database industry. , it can support CRUD (add, query, update, delete) operations of the database and has very powerful functions. SQL can use index-like methods to speed up query operations.

6, Normalization: During the database design and development process, developers usually face the need to operate on one or more data entities (including arrays, lists, and nested data) at the same time. , so in a relational database, a data entity must first be divided into multiple parts, and then the divided parts are normalized. After normalization, they are stored in multiple relational data tables respectively. This is a complex process. . The good news is that with the development of software technology, quite a few software development platforms provide some simple solutions. For example, you can use the ORM layer (that is, object relational mapping) to map the object model in the database to the SQL-based relational model. database and convert data between different types of systems.

7, Transactionality: Relational database emphasizes ACID rules (Atomicity, Consistency, Isolation, Durability), which can It meets data operations that require high transactional requirements or complex data queries, and can fully meet the requirements for high performance and operational stability of database operations. And relational databases place great emphasis on strong consistency of data and have good support for transaction operations. Relational databases can control the atomicity of transactions at fine granularity, and can roll back transactions immediately if an operation is incorrect or necessary.

8, Reading and writing performance: Relational databases place great emphasis on data consistency and pay a huge price for reducing reading and writing performance. Although relational databases store data and process data The reliability is very good, but once faced with the processing of massive data, the efficiency will become very poor, especially when encountering high concurrent reading and writing, the performance will drop drastically.

9, Authorization method: Common relational databases include Oracle, SQLServer, DB2, and Mysql. Except for Mysql, most relational databases require a high price to be used. Cost, even free MySQL performance is subject to many limitations.

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