History of Relational Database
Database system have been inseparable with our daily life, since IBM developed the hierarchical database management system in 1969, database system has been innovated many times, such as hierarchical database, network database, relational database, and object-oriented database. Nowadays, relational database still is the most popular model used by different industries; this article is going to introduce the history of the relational database.History of Relational Database Data, which can be defined as an entity of meaning, it is the original material to construct message and knowledge. Thanks to the assistance of computer, data processing practices reached several important milestones. The earliest way to store data are done through manual file management, all documents will be filed and then store, but this method had many processing restrict, such as search, storage takes up a lot of space, and cannot be access by people at the same time.
After IBM announced the first set of hard disk drive for data storage in 1956, due to the innovate development of hard drive, and the access speed much faster than magnetic tape, it replaced the tape drive gradually, and then direct access file system developed. Although direct access file system could access each files directly and improved a lot of missing, but since the objects are files, it still lack of flexibility of processing. Database can be considered to automatically query and modify data sets.There are a variety of database types; from the simplest store all kinds of information forms to large-scale database systems that able to process a variety of mass data storage, are widely used in all inspects of applications. The advantages of database management system:
- Reduced redundancy
- Integrated data
- Data commonality
- Protect data safety and privacy
The disadvantages of database management system:
- Overall operating cost will increase
- More complex to use
Need to backup regularly, or unexpected conditions will cause serious data damage
- Hard to training database administrator
- Difficult to integrate or manage different format from multi systems
Therefore, there was an idea about divide files into a sum of record, and store it as an unit in the computer, it also formed the “Centralized Database System”, it can record a record through hard disk drive, and can directly navigate to the record or fields for further data processing and computing. This concept also derived to the following data types:
Hierarchical Data Model (1960s)
Use record as a processing unit, and organize record by tree structure. As a result of the characteristic of tree structure, hierarchical data model particularly suitable for describe “One to Many” data composition relationship but “Many to Many” relationship.
Network Data Model (1970s)As a result of the tree structure does not reflect network connection relationship between data and data, so after hierarchical data model, some groups proposed “Network Data Model”, organize records by network structure. However, records in both Hierarchical data model and network data model use link to strung together, so when programming applications must accommodate the structure status between links, a lot of dependencies between programming applications and data structure, and the independence of data is hard to reach, cause the system difficult to maintain. Relational Data Model (1970 ~ present) Edgar Codd, a British computer scientist, proposed “Relational Data Model in 1970, emphasize the applications should not have any dependencies with internal structure of data, it also known as “Data Independence”, this data model lead the development of the database system entered a new milestone. In relational data model, data use record as a processing unit, and organize record in tabular form. The applications just face to the tabular structure, without to understanding the internal structure of the data. Conclusion Relational Database Management System (Relational DBMS) is the most widely used database management system in recent years, the mainly reason is the concept of relational data models is simple, and the basic theory was developed very completely. Since Relational Database management System be proposed in 1970, almost all the commercial database management systems are based on this model. We often hear of the data table, is a relational database foundation.
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