PHP database development knowledge

PHP database development knowledge, PHP database development knowledge, PHP learning continues, but some friends in some large PHP exchange forums are not clear about the most basic database concepts, this leads to the idea of writing this article! (1) concept database is a set of information in one, each set contains one or more unified records, records are composed of fields. usually set "> <LINKhref =" http://www.php

PHP learning is still going on. However, in some large PHP exchange forums, some friends are not clear about the basic database concepts, and the idea of writing this article is generated!
(1) concepts

A database is a set of information. Each set contains one or more unified records. records are composed of fields. generally, a set is called a table and a record is called a row in a table.
Databases are generally divided into flat file databases (TEXT), hierarchical databases, network databases, relational databases (mysql), object and object relational databases!

(2) Relational databases are the liberation of software development for programmers

Because the platform file database must directly contact the operating system, when the application needs to edit this information, it must ensure that the field and the form are correct. this kind of interface is expensive, because she needs a 3rd-generation language (3GL) and someone with high skills to develop it for a long time! For example, a programmer must consider the logical and physical representation of data. for example, to read an integer from a file, the programmer must know whether it is written in text or binary form. Certain conventions must be observed when data flows between files and applications. Therefore, the efficiency of the flat file database program generally depends on the programmer's hard work and level! Compared with MYSQL, MYSQL achieves data independence and structure independence! Therefore, programmers do not have to bear the burden of data management! Aside from the internal details of database processing! This is the most important reason for the emergence of RDBMS! That's why she popularized it!

(3) excellent programs-object relational database model

In the database model, MYSQL is a relational database, but the relational model is not the patent of MYSQL. the innovation of the database theory is continuing. some basic principles of advanced technology can also be used in relational models, if you are a programmer proficient in 3GL, using a flat file database can not only develop excellent programs! In addition, it has great advantages in data processing, programming control, and resource utilization at the grassroots level! If you need to read and write a large amount of data frequently !, You can use the positioning pointer to read the specified data and set the length of the index. The so-called load problems can be solved, and the control is flexible, convenient, and secure, the concurrency model of the hierarchy and network model can be used! Of course, the most important thing is the programmer's sensitivity. well-designed index tables are important!
The main advantage of MYSQL is its physical storage: MYLSAM tables support three row modes and the idea of fixed-length rows for flexible data processing, and use file descriptors to read and write tables, the buffer and cache in the system memory are all the reasons for MYSQL's fast data processing capabilities! At the same time, you can use physical storage to facilitate data repair and fragment!

I believe that as long as you have excellent database models, no matter what type of database you use, you must develop excellent programs!