A database is a collection of data stored together in some way, which can be shared by multiple users, has as little redundancy as possible, and is independent of applications. It can be regarded as an electronic filing cabinet-a place where electronic files are stored, and users can add, query, update and delete the data in the files.
A database is a warehouse for storing data. Its storage space is very large, and it can store millions, tens of millions and hundreds of millions of pieces of data. But the database does not store data at will, and there are certain rules, otherwise the query efficiency will be very low.
Today's world is an internet world full of data, full of a lot of data. That is, this internet world is the data world. There are many sources of data, such as travel records, consumption records, web pages visited, messages sent and so on. Besides text data, images, music and sounds are all data.
Extended data
Development situation
In the history of database development, database has experienced various stages of development, such as hierarchical database, network database and relational database, and database technology has developed rapidly in all aspects. In particular, relational database has become the most important member of database products.
Since 1980s, almost all the new database products of database manufacturers have supported relational databases, and even some non-relational database products have almost interfaces supporting relational databases. This is mainly because the traditional relational database can better solve the problem of managing and storing relational data.
With the development of cloud computing and the arrival of the era of big data, relational databases can't meet the demand more and more, mainly because more and more semi-relational and non-relational data need to be stored and managed by databases. At the same time, the emergence of new technologies such as distributed technology also puts forward new requirements for database technology, so more and more non-relational databases begin to appear.
This kind of database is very different from the traditional relational database in design and data structure. They emphasize the high concurrent reading and writing of database data and the storage of big data. This kind of database is generally called NoSQL (not just SQL) database. However, the traditional relational database still maintains strong vitality in some traditional fields.