Similar processing is done by a web-based system , as illustrated by the second example in this figure. In thjs case, though, a web brotvser running on the client is used to send requests to a web application running on a web server somewhere on the Internet. The web application, in turn, can use web services to perform some of its processing.
Then, the web application or web service can pass requests for data on to the database server. For example, business components can be distributed over any number of application servers, and those components can communicate with databases on any number of database servers. Similarly, the web applications and services in a web-based system can be distributed over numerous web servers that access numerous database servers.
In most cases, though, you don' t need to know how a system is configured to use SQL. For example, traditional mainframe systems and newer thin client systems also use SQL. The terminals or PCs that are connected to the system do little or no work. Application servers are typically used to store business comporients that do part of the processing of the application. In particular, these components are used to process database requests from the user interface running on the client.
Web applications are applications that are designed to run on a web server. Web services are like business components, except that, like web applications, they are designed to run on a web server.
Then, the web server processes the request and passes any requests for data on to the database server. More complex system architectures can include two or more application servers, web servers, and database servers. Codd developed a model for a new type of database called a relational database. Thjs type of database eliminated some of the problems that were associated with standard files and other database designs. By using the relational model, you can reduce data redundancy, which saves disk storage and leads to efficient data retrieval.
You can also view and manipulate data in a way that is both intuitive and efficient. Today, relational databases are the de facto standard for database applications. How a table is organized The model for a relational database states that data is stored in one or more tables. It also states that each table can be viewed as a two-dimensional matrix consisting of rows and columns. This is illustrated by the relational table in figure Each row in this table contains information about a single vendor.
In practice, the rows and columns of a relational database table are often referred to by the more traditional term s, records and. In fact, some software packages u se one set of terms, some use the other, and some use a combination.
In general, each table is modeled after a real-world entity such as a vendor or an invoice. Then , the columns of the table represent the attributes of the entity such as name, address, and phone number. And each row of the table represents one instance of the entity. A value is stored at the intersection of each row and colu1nn, sometimes called a cell.
If a table contains one or more columns that uniquely identify each row in the table, you can define these columns as the primary key of the table. In this example, the primary key consists of a single column. However, a primary key can also consist of two or more columns, in which case it's called a composite primary key. In addition to primary keys, some database management systems let you define additional keys that uniquely identify each row in a table.
In MySQL, this is called a unique key. Indexes provide an efficient way of accessing the rows in a table based on the values in one or more columns. Because applications typically access the rows in a table by referring to their key values, an index is automatically created for each key you define.
However, you can define indexes for other columns as well. If, for example, you frequently need to sort the Vendor rows by zip code, you can set t1p an index for that column. Like a key, an index can include one or more columns. To buy this book from the official publisher click on the Buy this book button. Add Comment. Save my name, email, and website in this browser for the next time I comment. Post Comment. Chapter 13 shows you how to work with forms and data validation. Chapter 14 shows you how to enhance a site with video clips.
Chapter 16 shows you how to use CSS3 transitions, transforms, and animations. Chapters 17 and 18 show you how to design and deploy a website. And after you've learned all the skills that you need, this book becomes the best on-the-job reference you've ever used.
If you're developing websites, you have to know JavaScript. There's no way around it today. And this latest edition of Murach's popular book teaches you how to code modern JavaScript that conforms to the ECMAScript standards, the way the pros do. At the same time, it teaches you how to use jQuery, the classic JavaScript library, to handle the DOM scripting that gives JavaScript so much of its power.
If you're an application developer, or you're training to be one, this latest edition of Murach's classic SQL Server book is made for you.
To start, it presents the SQL statements that you need to retrieve and update the data in a database. These are the SQL statements that you'll use every day. The result? You'll be able to create database applications that are thoroughly professional. You'll be familiar with the DBA-related issues that let you work far more effectively than most of your colleagues. And you'll have a handy reference at your side to answer questions and handle new challenges as they come up. How do you approach answering queries when your data is stored in multiple databases that were designed independently by different people?
This is first comprehensive book on data integration and is written by three of the most respected experts in the field. This book provides an extensive introduction to the theory and concepts underlying today's data integration techniques, with detailed, instruction for their application using concrete examples throughout to explain the concepts. Data integration is the problem of answering queries that span multiple data sources e.
Data integration problems surface in multiple contexts, including enterprise information integration, query processing on the Web, coordination between government agencies and collaboration between scientists. In some cases, data integration is the key bottleneck to making progress in a field.
The authors provide a working knowledge of data integration concepts and techniques, giving you the tools you need to develop a complete and concise package of algorithms and applications. Offers a range of data integration solutions enabling you to focus on what is most relevant to the problem at hand Enables you to build your own algorithms and implement your own data integration applications.
This comprehensive and user-friendly book is the first and maybe even the only starter-level work of its kind combining the naturally complimentary JSP, JSF and Tomcat Web technologies into one consolidated treatment for developers focusing on just Java Web application development and deployment.
This book is examples-driven using practical, real-time e-commerce case studies and scenarios throughout. Beginning C Object-Oriented Programming brings you into the modern world of development as you master the fundamentals of programming with C and learn to develop efficient, reusable, elegant code through the object-oriented programming OOP methodology.
Take your skills out of the 20th century and into this one with Dan Clark's accessible, quick-paced guide to C and object-oriented programming, completely updated for. NET 4. With more than 30 fully hands-on activities, you'll discover how to transform a simple model of an application into a fully-functional C project, including designing the user interface, implementing the business logic, and integrating with a relational database for data storage.
Along the way, you will explore the. NET Framework, the creation of a Windows-based user interface, a web-based user interface, and service-oriented programming, all using Microsoft's industry-leading Visual Studio , C , Silverlight, the Entity Framework, and more. If you want to learn how to program but dont know where to start, this is the right book and the right language for you.
From the first page, our self-paced approach will help you build competence and confidence in your programming skills. Section 2 takes you deeper into PHP by covering the skills youll use every day, like how to work with form data, dates, arrays, sessions, cookies, functions, objects, regular expressions, and exceptions. Likewise, Section 3 dives into MySQL, teaching you how to design and create a database, as well as how to access and maintain database data from your PHP programs.
Finally, Section 4 teaches you important web programming skills like how to secure web pages, send email, upload files, and process images.
0コメント