In order to create a proper database design, first the architect of the data base must determine the objectives for the database and also the high-level requirements.
1. The first step that would be helpful is creating a sketch while exposing the logical database design. Based on the input information, tables with their attributes must be defined. Tables which are called also entities, ... Continuare
Concepts in relational database design
The relation database design is based on the relational concept approach which describes the information in the manner of predicate logic and truth statements. The relation between this concept and the relational database design is the following: when needing stored information in a database, information about selection criteria must be provided. These are in the form of a logic model, ... Continuare
Database servers
Starting from the data definition, this term can refer anything that can be stored as the data owner needs to maintain its reference in a specific place, from where he can retrieve, update or delete. For keeping in a well defined manner all this data owners, databases were created, with the purpose of defining an electronic mean through which data can be stored in an organized manner.
Any ... Continuare
Models in architecting Java Web Applications
The terms for the two architectural designs for Java Web Applications first appeared in the early drafts of the JSP specifications: Model 1 and Model 2.
1.Model 1 architecture: Page-centric
In this architecture, the application is page-centric. The client browser navigates through a series of JSP pages in which any JSP page can employ a JavaBean that performs business operations. However, ... Continuare
Layers architecture for J2EE Applications
Reviewing the software system architecture, layers of an application are separated logic parts that belong to the application. The same layers stands also in the J2EE Application. The description of layers, now taking into consideration the web components from J2EE platform, is presented below:
o Presentation layer: This layer is made up of Java Server Pages (JSP) which are basically HTML ... Continuare
Tomcat Servelt Container
Through all the servlet containers on the market today the Tomcat servlet/JSP container is recognized as the official one. Originally designed by Sun Microsystems, Tomcat source code was handed over to the Apache Software Foundation in October 1999. Here, Tomcat was included as part of the Jakarta Project, one of the projects of the Apache Software Foundation.
Tomcat by actually a web ... Continuare
Java Server Pages
According to Sun s web site, "JSP technology is an extension of the servlet technology created to support authoring of HTML and XML pages". Java Server pages appeared as the technology of using servlets showed out some disadvantages. One of the disadvantages is that for a simple Http response page, the code was quite large because it had to declare parameters, methods, writing HTML tags, etc. ... Continuare
Servlet Application Architecture
The basic architecture of an application that involves processing of servlets, and thus, implies the existence of the servlet container, which communicates with the clients requests by the HTTP protocol. The servlet container it will be replaced by a JSP container in the context of JSP page files usage. Their role is the same.
There are two configurations for the architecture of a servlet ... Continuare
J2EE web components
2.1 Servlet
The Java Servlet API is one of the most important technologies included in the J2EE platform, providing utility in building dynamic content. It is directly related to another successful technology, Java Server Pages. Regarding the approaches, the java servlet is similar as role and objectives with other technologies like ASP.
A servlet is a java class that can be loaded ... Continuare
J2EE platform
For developing multi-tier application as web-applications, the software architect needs a reliable and robust platform to build the system on. One of the most famous and used platforms in nowadays web-application is the Java platform J2EE. The name of the platform comes from Platform Java 2 Enterprise Edition.
J2EE is a programming platform, designed for developing and running distributed ... Continuare
Tier architecture
Designing robust system architecture it is critical for the success of the application. All the interconnections between components, their divisions in layers must be the focus of the architecting process.
A short history over the application architectures sounds like this: first there were the standalone applications (if they wanted however to manipulate data, they were doing this by ... Continuare
Logic levels in a software system
A well-designed software application based on the Client/Server model is divided into separate logical parts called layers or levels. Each layer has a different responsibility in the overall architecture. These layers are purely abstractions, and do not correspond to physical distribution. The logic levels and the interconnection between them represent the most common design of a transaction ... Continuare
Identifying the Software Technology for a System architecture
After identifying the objectives and the principle targets of the system, the wide array of potential technologies available on the market must be taken into analysis for the best usable technology; the evaluation of the technology that can be used while designing the architecture of a system must include a matrix that identifies the technology, the benefits of the technology, and the ... Continuare
Fulfill requirements: functional and not-functional
Along with the architecture goals, there also must be taken into consideration non functional requirements, which are critical success factors in developing the architecture.
The nonfunctional requirements of the system identify what the system must achieve for itself in order for it to be considered successful. Those requirements differ from the architecture system goals by the fact they ... Continuare
Objectives of the System Architecture
There are some general principles that are usually applied during the architectural process. These principles described bellow, guide the analysis and decision taking that must be performed during the process. The principle is to conceive an architecture that has follows the features described below:
• Has clarity – the objective is to create a system that can be easily understood. Even ... Continuare
Defining the System Architecture concept
The official definition of architecture is the study of design; the differences between design and an architecture is that design can be performed individually, while the architecture is a module, framework that can be applied in general situations with specific features. Architecting something means arrangements of parts or structure in a proper order. This is no difference to the case of ... Continuare
TCP/IP protocol – communication protocol
The term TCP/IP stands for Transmission Control Protocol / Internet Protocol, otherwise translated as the communication protocol for communication between computers connected to the Internet.
The standard TCP/IP-a communication protocol- is a package of rules descriptions regarding the communication between computers, how should they be connected to the Internet and how should data be ... Continuare
HTTP Response
• Protocol + Status code + Description
Ex: HTTP/1.1 200 OK
o the first line (or initial line) in the response output the HTTP protocol name/version, the response status code and the reason phrase describing the status code
• Response headers
o The headers are similar to the response headers, containg information about the content of the message body(Content-type, Content-Length) and ... Continuare
HTTP Request
• Request Method + URI + Protocol/Version
Ex: GET /stone/index.jsp HTTP/1.1
o many request methods can be used in the header of a request: GET, HEAD, POST, OPTIONS, PUT, DELETE, TRACE
GET is the most simple and used method that retrieves data identified in the URL; if the URL refers to a script (CGI, servlet, etc) it returns the data produced by the script.
o The URI ... Continuare
HTTP protocol
The name of HTTP protocol comes from Hyper Text Transfer protocol and basically is the protocol that allows servers and browser to exchange data on the Internet. Being a protocol that is used in client/server model system architecture, it is designed for treating and managing the requests and replies from clients, respective servers. It is the standard protocol that is used on the ... Continuare
