Relational Database Management System (RDBMS)

The relational database management system (RDBMS) is a database engine / system based on the relational model specified in 1970 by Edgar F. Codd, the father of modern relational database design.

Most modern commercial and open source database applications are inherently relational. The most important relational database features include the ability to use tables for data storage while maintaining and implementing specific data relationships.

In 1970 IBM's British computer scientist Edgar F. Cod announced "Data Relation Model of Large Scale Database". At the time, this famous paper attracted a lot of attention, but few people understood how the basic rules of relational data storage are defined by Codd's innovative work.

Data must be stored and represented as relationships, that is, tables with relationships, such as primary keys and foreign keys.

In order to manipulate the data stored in the table, the system must provide relational operators - these codes can test the relationship between two entities. A good example is the WHERE clause of the SELECT statement. That is, the SQL statement SELECT * FROM CUSTOMER_MASTER WHERE CUSTOMER_SURNAME = 'Smith' queries the CUSTOMER_ MASTER table and returns all customers with the last name Smith.

Codd later published another paper outlining the 12 rules that all databases must comply with in order to qualify as a relationship. Most modern database systems do not follow all 12 rules, but these systems are considered relational because they conform to at least two of the 12 rules.

Most modern commercial and open source database systems are inherently related and contain well-known applications such as Oracle DB (Oracle), SQL Server (Microsoft), MySQL and Postgres (Open Source).

There are basically three types of database management systems. Relational database management system (RDBMS), object relational database management system (ORDBMS), and object oriented database management system (OODBMS). The RDBMS handles the relationships between the databases and uses the relational data model. An ORDBMS is similar to an RDBMS. The operating principle of the ORDBMS is based on objects, classes, and inheritance in the database schema and is also based on Structured Query Language (SQL). It is also known as an intermediate point between RDBMS and OODBMS. Finally, in OODBMS, databases are represented as objects in the same way as object oriented programming (OOP).

A relational database management system (RDBMS) supports a relational (table-oriented) data model. The schema of the table (relational schema) is defined by a table name and a fixed number of fixed data type attributes. A record (entity) corresponds to a row in the table and consists of the value of each attribute. Therefore, a relationship consists of a series of consolidated records. The central concept of document storage is the concept of "document". The implementation of each document-oriented database differs in the details of this definition, but in general they assume that the document encapsulates and encodes data (or information) in some standard format or encoding. The encodings used include XML, YAML, and JSON, as well as binary formats like BSON. Process the documents in the database by representing the unique key of the document