Introduction of database

A database is an information system with the four characteristics of "data consistency," "data independence," "data availability," and "data confidentiality."Databases are mainly effective in managing the enormous and diverse data known as "big data."

。As the name suggests, a hierarchical database is a database that arranges data in a tree-like format.
In this database, information is managed in a one-to-many state from top to bottom. The advantage is that it is easy to find data because the path to the data you are looking for is one-way. However, the disadvantage is the possibility of duplicate information.

A network structure database is a method of storing related data by linking them to each other. It is a hierarchical database that allows information to be traced from the bottom to the top. This allows a many-to-many relationship to be established and reduces data duplication, which was a disadvantage of hierarchical databases.

Relational databases, or RDB for short, use a method of managing data in the form of multiple tables, similar to Excel.
The advantages are that it is easy to organize and visually understand even complex related data because it is managed in a table. However, it also has the disadvantage that the program itself to manage the data becomes more complex.
It is also currently the most mainstream database.

A database management system is a system that automatically manages and operates databases.
Although databases cannot automatically manage and organize data on their own, a database management system enables automatic management and reduces human error.
In addition, the database management system can also prevent erroneous data entry in advance by displaying a warning message when duplicate data entry is about to occur.