What is a database?
Simply put, a database (English Database) is a warehouse that stores data. This warehouse is based on certain data results (data structure refers to the organization form of data or the relationship between data) For organization and storage, we can manage the data in the database through the various methods provided by the database. A simpler image understanding is that the database is the same as the warehouse where we store sundries in our lives. The only difference is that the things stored are different.
Types of databases
There were three popular early database models, namely hierarchical databases, network databases and relational databases. In today's Internet, there are two main types of database models commonly used, namely relational databases and non-relational databases.
Relational database
The relational database model reduces complex data structures into simple binary relationships (ie, two-dimensional table form).
Commonly used relational databases:
MySQL, MariaDB database, SQL Server database, Access database
Non-relational database
Non-relational databases are also called NoSQL databases. The original meaning of NOSQL is "Not Olnly SQL"
refers to non-relational databases, not "NoSQL". Therefore, the emergence of NoSQL is not to be completely It negates non-relational databases, but serves as an effective supplement to traditional relational databases. NOSQL databases can achieve unimaginable efficiency and performance in specific scenarios.
Commonly used non-relational databases:
memcached (key-value), Redis (key-value), MongoDB (Document-oriented), Cassandra (Column-oriented)
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