Explaining the PHP Framework (1) Basic Concepts_PHP Tutorial

LAMP

LAMP is an open resource web development platform based on Linux, Apache, MySQL and PHP. The term comes from Europe, where these programs were commonly used as a standard development environment. The name is derived from the first letter of each program. Each program adheres to open source standards in its ownership: Linux is an open system; Apache is the most versatile web server; MySQL is a relational database with additional tools for web-based administration; PHP is a popular object scripting language that includes It has many of the best features of other languages ​​to make web development more efficient. Developers who use these tools in the Linux environment under the Windows operating system are called using WAMP.

Although these open source programs themselves are not specifically designed to work with several other programs, because they are all influential open source software and share many common characteristics, these components are often used together. use. Over the past few years, the compatibility of these components has continued to improve, and their use together has become more common. And they have created certain extensions to improve collaboration between different components. Currently, these products are included by default in almost all Linux distributions. Linux operating system, Apache server, MySQL database and Perl, PHP or Python language, these products together form a powerful web application platform.

With the vigorous development of the open source trend, open source LAMP has formed a tripartite confrontation with J2EE and .Net commercial software, and the software development project has a low investment cost in software, so it is favored by the entire IT community. focus on. In terms of website traffic, more than 70% of the access traffic is provided by LAMP. LAMP is the most powerful website solution.

OOP

Object-oriented programming (Object Oriented Programming, OOP, object-oriented programming) is a computer programming architecture. A basic principle of OOP is that a computer program is composed of a single unit or object that functions as a subroutine. OOP

The three main goals of software engineering are achieved: reusability, flexibility and extensibility. In order to realize the overall operation, each object can receive information, process data and send information to other objects. OOP mainly has the following concepts and components:

　Component - a unit of data and functionality that together form a running computer program. Components are the basis of modules and structure in OOP computer programs.

Abstractness - the ability of a program to ignore certain aspects of the information being processed, that is, the ability to focus on the main aspects of the information.

Encapsulation - also called information encapsulation: ensures that components will not change the internal state of other components in unexpected ways; only those components that provide internal state changing methods can access their internal state. Each type of component provides an interface to communicate with other components and specifies methods for other components to call.

Polymorphism - Component references and class sets involve many other different types of components, and the results generated by the referenced component depend on the actual type of call.

Inheritance - allows the creation of subclassed components based on existing components, which unifies and enhances polymorphism and encapsulation. Typically, classes are used to group components, and new classes can also be defined as extensions of existing classes, so that classes can be organized into a tree or network structure, which reflects the versatility of actions.

Component-based programming has become particularly popular in scripting languages ​​due to reasons such as abstraction, encapsulation, reusability, and ease of use.

MVC

MVC is a design pattern that enforces separation of application input, processing, and output. Using MVC, an application is divided into three core components: model (M), view (V), and controller (C), each of which handles its own tasks.

View: A view is the interface that users see and interact with. For old-fashioned Web applications, the view is an interface composed of HTML elements. In new-style Web applications, HTML still plays an important role in the view, but some new technologies have emerged in endlessly, including Adobe Flash and Some markup languages ​​and Web services like XHTML, XML/XSL, WML, etc. How to deal with an application's interface is becoming more and more challenging. One of the big benefits of MVC is that it can handle many different views for your application. No real processing occurs in the view, whether the data is stored online or a list of employees. As a view, it just serves as a way to output the data and allow the user to manipulate it.

Model: Model represents enterprise data and business rules. Among the three components of MVC, the model has the most processing tasks. For example, it might use component objects like EJBs and ColdFusion Components to handle databases. The data returned by the model is neutral, which means that the model has nothing to do with the data format, so that a model can provide data for multiple views. Code duplication is reduced because the code applied to the model only needs to be written once and can be reused by multiple views.

Controller: The controller accepts user input and calls models and views to complete the user's needs. So when a hyperlink in a Web page is clicked and an HTML form is sent, the controller itself does not output anything or do any processing. It just receives the request and decides which model component to call to handle the request, and then determines which view to use to display the data returned by the model processing.

Now we summarize the MVC processing process. First, the controller receives the user's request and decides which model should be called for processing. Then the model uses business logic to process the user's request and returns the data. Finally, the controller uses the corresponding view format. The data returned by the model is transformed and presented to the user through the presentation layer.

CURD

CURD is an abbreviation in database technology. The basic functions of various parameters in general project development are CURD. It represents Create, Update, Read and Delete operations. CURD defines basic atomic operations for processing data. The reason why CURD is elevated to the level of a technical difficulty is that the performance of completing an aggregation-related activity involving CURD operations in multiple database systems may vary greatly as the data relationships change.

CURD does not necessarily use the create, update, read and delete methods in specific applications, but the functions they complete are the same. For example, ThinkPHP uses the add, save, select, and delete methods to represent the CURD operations of the model.

Single entrance

A single entry usually means that a project or application has a unified (but not necessarily unique) entry file, which means that all functional operations of the project are performed through this entry file, and the entry file is often the first One step is executed.

The advantage of a single entrance is that the overall project is relatively standardized, because the same entrance often has the same rules for different operations. Another aspect is that the benefit of a single entrance is that the control is more flexible, because interception is convenient, and judgments and operations such as some permission controls and user logins can be processed uniformly.

Or some people may worry about whether all websites are accessed through one entry file, which will cause too much pressure. In fact, this is an unfounded idea.

ORM

Object/Relation Mapping (ORM for short) was born with the development of object-oriented software development methods. The object-oriented development method is the mainstream development method in today's enterprise-level application development environment, and the relational database is the mainstream data storage system that permanently stores data in the enterprise-level application environment. Objects and relational data are two forms of expression of business entities. Business entities are represented as objects in memory and as relational data in the database. There are associations and inheritance relationships between objects in memory, but in the database, relational data cannot directly express many-to-many associations and inheritance relationships. Therefore, object-relational mapping (ORM) systems generally exist in the form of middleware, which mainly implements the mapping of program objects to relational database data.

Object-oriented is developed based on the basic principles of software engineering (such as coupling, aggregation, encapsulation), while relational database is developed from mathematical theory. There are significant differences between the two sets of theories. In order to solve this mismatch phenomenon, object-relational mapping technology came into being.

http://www.bkjia.com/PHPjc/477845.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/477845.htmlTechArticleLAMP LAMP is an open source web development platform based on Linux, Apache, MySQL and PHP. The term comes from Europe, where these programs were commonly used as a standard development environment. Origin of the name...