PHP learning is still going on, but in some large PHP exchange forum encountered some friends on the most basic database concept is not clear, then produced the idea of writing this article!
(i) Concept
A database is a collection of information in which each collection contains one or more uniform records, and the records consist of fields. Typically, a collection is called a table, and a record is called a row in a table.
The database is generally divided into: Flat file Database (TEXT), hierarchical database, network database, relational database (MySQL), object-to-Object relational database!
(ii) Relational database is the liberation of programmer Development Software
Because of the flat file database, you must contact the operating system directly, and when the application needs to edit this information, you must make sure that the fields are in the correct form. This form of interface is expensive because she needs a 3rd generation language (3GL), requiring highly skilled personnel to develop for a long time! For example, a programmer must consider the logical and physical representations of data, such as reading an integer from a file, and the programmer needs to know whether it is written in textual or binary form. When data flows between files and applications, certain conventions must be followed. Therefore, the efficiency of the flat file database program is generally determined by the programmer's hard work and level! Compared to MySQL because of the realization of the independence of the data, but also achieve the independence of the structure! So programmers don't have to bear the burden of data management! This is the most important reason for RDBMS to produce ! is the reason for her popularity!
(iii) Excellent program--Object relational Database model
Database model, MySQL is a relational database, but the relational model is not the patent of MySQL, the innovation of database theory is continuing, some basic principles of advanced technology can also be used in relational models, if you are proficient in 3GL programmer, using flat file database can not only develop excellent program! And in the basic data processing, programming control, resource utilization, have a great advantage! If you need to read and write a lot of data frequently!, you can use the positioning pointer to read the specified data, fixed-length index, so-called load problem, solve, control is also very flexible, convenient, security issues, hierarchical and network model of the concurrency model can be used! Of course, the most important is the sensitivity of the programmer, Well-designed index table, it is important to set off!
And the advantage of MySQL mainly lies in his physical storage: Mylsam Table supports 3 kinds of lines and fixed-line thinking of data processing flexibility, and the use of file descriptors to read and write tables, system memory buffer and cache are the reason why MySQL fast data processing capabilities! At the same time you can take advantage of the physical storage to facilitate the data repair, defragmentation and so on!
I believe that as long as you have a good database model, no matter what type of database you use, you have developed a good program!
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