1、Mysql .
MySQL was originally an open source relational database management system. The original developer was MySQL AB of Sweden, which was acquired by Sun Microsystems in 2008. In 2009, Oracle Bone Inscriptions acquired Shengyang Microsystems, and MySQL became a product of Oracle Bone Inscriptions.
MySQL has become the most popular open source database because of its high performance, low cost and good reliability, so it is widely used in small and medium-sized websites on the Internet. With the continuous maturity of MySQL, it is gradually used by more large websites and applications.
2、PostgreSQL .
PostgreSQL can be said to be the most powerful, functional and complex open source database management system at present, some of which are not even available in commercial databases. This database, which originated from the University of California, Berkeley, has become an international development project with a wide user base, especially overseas, and there are more and more domestic users at present.
PostgreSQL has basically witnessed the development of the whole database theory and technology. It was founded by michael stonebraker, a computer professor at UCB, in 1986. Prior to this, Professor Stonebraker led the research project of relational database Ingres, and put forward the first prototype design of Postgres in 1988.
MySQL claims to be the most widely used open source database, while PG is called the most powerful open source database.
3. Microsoft SQL server.
SQL Server is a relational database management system (RDBMS) developed by Microsoft, and now it is the most commonly used database in the world. SQL Server now includes built-in business intelligence tools and a series of analysis and reporting tools, which can create databases, backup, copy, be more secure and more.
SQL Server is a highly scalable product that can run anything from a laptop or a high-performance cloud server network, or anything in between. Although it is "anything", it still needs to meet the requirements of related software and hardware.
4.Oracle database.
Oracle database system is a set of software products with distributed database as the core provided by Oracle (Oracle Bone Inscriptions) Company of the United States, and it is one of the most popular databases with client/server (C/S) or browser/server (B/S) architecture.
Oracle database is the most widely used database management system in the world. As a general database system, it has a complete data management function. As a relational database, it is the product of complete relationship; As a distributed database, it realizes the distributed processing function.
5、MongoDB
MongoDB is an open source product between relational database and non-relational database, and it is the NoSQL database closest to relational database. It is an extension of lightweight JSON exchange and is called BSON to describe its unstructured data types. However, it can also store more complex data types.