Web Developer Resources

Image source: www.xquery.com

XQuery was made so that there was a way to query data stored in an XML document, much the same way SQL is used to query a database.

XQuery uses simple functions to query a document. An XQuery function looks a little like a javascript function in that it uses parentheses containing an element that is to be the object of the function. With XQuery, the element in parentheses is typically the name of the document or file to be queried.

To find what it is looking for within that file, XQuery narrows its search by using path expressions that look a lot like the path for an ordinary file stored on your computer, with the various subsets of data within the XML file separated by backslashes. The predicate is the final component of an XQuery function. The predicate tells the function exactly what information, data, or range of data within a particular subset is to be extracted and returned to the user.

Exposing a database as a Web Service, you first need to have the entire database around, to create a very simple database with one table to store personal information. Its table will have four fields to store ID, name, address, and age. This sample application is based on My SQL databases, but you can do the exact same thing with any given database. You can add much more data if you want. You can either insert data by running SQL or you can just insert all the data by using the My SQL Query Browser. When listing the names of all the persons in the DB, you just need to return the String array.

There are a huge number of approaches that industries have employed when they want to expose their databases as Web Services. The Data Service approach can be considered as one of the best approaches, and you can find a huge number of different Data Services solutions as well. You can consider the WSO2 Data Service solution as a best example candidate for a Data Service solution that is built on Axis2. You can consider that as exposing a database by using Axis2 POJO to get a better understanding about this approach. Having a good knowledge about Axis2 will be an added advantage

A strong data typing is lost with a vertical table, because the value column is of only one type and all values need to be either of that type or need to be converted back and forth during save and retrieve operations. Storing special data types like Blobs or Clobs is very impossible in the vertical table. Another drawback is the data consistency. The fact that all column names are entries in the key column makes it much easier for the users to store potentially identical data with differently called keys. Also, working with a vertical table is harder in finding the specific a logical row.

Vertical data stores a different, dynamic logic on the application layer and the UI. Because the data can be stored as the key/value pairs in only two columns and it is tied together in a logical form by a unique id, there’s no limitation on how many fields can be in a form. Subsequently, each of the logical rows in vertical table can have various numbers of fields. Therefore, the largest advantage of the vertical data organization is its flexibility, but there are still numerous disadvantages. With flexibility, the control over of data is lost, which means the data normalization is very hard thing to maintain.

There are many advantages of storing data in the traditional horizontal fashion, but there are also its shortcomings. If you are designing an application that has a complete dynamic screen, and there is no concrete field of number or names, All the users can create a new field, and give a name and a value. Now if a form is created based on a business requirement that has some specified business-required fields, the data per form is stored in a horizontal table in which each field is inserted in a specific column and each form is stored as a row.

Whether you are looking to build your first site or want to make your current site stronger, better, faster and fancier, there are a lot of things that you can do. Probably the easiest and best way to make your static site fancier is to use JavaScript. You can also consider including forms and optimizing your site to increase the volume of traffic. You can create your own dHTML to perk up user experience when visiting your site.

A must have in every site to engage a user is to add rollovers and flash animations. If you want to take it a step further, then its time to apply those color codes, special characters, browser charts and other special treats. Now, if you want to hype it up as in mainstream big time, buckle down to work and start learning the fundamentals of AS, JSP, PHP, ColdFushion and other scripting languages to give you that professional look.

Source: webmonkey.com