Relationship between sql and xml

What is the advantage of using XML with regards to SQL? - Stack Overflow

relationship between sql and xml

This article describes an application of (a simple subset of) XML that can be used to represent . xml default address xml-sqltype="varchar" xml-sqlsize="40"?> . The directory path specified for the mapping schema ( is relative to the directory where the template is saved. An absolute. XML (Extensible Markup Language) is a declarative text-based syntax used in formating data structure, has been used in structuring information in document.

We came up with a document that had about 90 queries, so we took about seven query languages and tried them out with these 90 queries. None of them were perfect. What was it about these use cases that made them unusual? The fundamental thing about them was that they relied on the structure of XML. XML's logical structure is based on hierarchy and sequence. Two things that relational databases don't do is hierarchy and sequence.

Yet Web sites typically get a lot of information from databases, but they don't put two-dimensional tables up on the screen. You create hierarchies for that information. In XML you structure everything with hierarchy and sequence. So how can XQuery help in that sort of situation? Let me give you a scenario. Your Web site has a message coming in: Someone wants to ask for the price of some stocks. Now we can join XML documents and various relational tables. The XML documents will identify the person who wants the information.

It will give the data range that person is interested in.

relationship between sql and xml

We join that against a relational database to figure out how the stocks have performed, and we build an XML structure that contains the result. It seems as if there is some resistance to the idea of using XML as a database tool from the relational database community.

relationship between sql and xml

Yeah, I read your interview with [database consultant] Fabian Pascal. It depends on who you're talking about. Certain purists don't like it. If you remember back in the early days, some of the people who are kicking back against XQuery now were kicking back then against the use of null in SQL [to represent missing data]. They are the people for whom SQL and real relational databases just aren't pure enough and what should have existed never really got implemented.

If you go to the major database conferences, you will see a lot on XML. Every relational database vendor has added XML support. People are very conservative about their database choices. But the flow of information is just as important as the control of information.

For most information, if you want to exchange it, you use XML. People don't give every Tom, Dick and Harry a connection to their databases. And the way you get through the firewall is to send XML around. It seems repetitive to add an XML tag to each record in a database.

relationship between sql and xml

Don't XML databases require more storage space than relational ones? I think you are confusing physical characteristics with logical characteristics. Connection properties On this screen, select a name for the JDBC Connection Pool, and set the additional database parameters such as database name, host name, port to connect, user name, and password.

This sample exists on almost every Oracle installation, therefore it should not require any additional configuration from your side. After you have properly configured these parameters, click Continue Figure 3. Connection test Generally you don't need to change anything on this page. This is a connection test page which you can skip by clicking the Skip This Step button. After you have reviewed these parameters you are ready to test.

Click the Test Driver Configuration link, and if everything is correct, you will see the "Connection Successful" message.

relationship between sql and xml

You'll get to the Data Source configuration page Figure 4. Remember the JNDI path; we'll use it later to set up a connection from our code.

Next select Continue, and then choose the correct connection pool to associate with the Data Source. Select the Connection Pool that you just created, and click Continue. The next page allows you to select servers and clusters on which to deploy the Data Source. Check the necessary ones from the list, and then click Create. The Data Source has been created and we ready to start writing the code.

Preparing the Environment for a Stand-Alone Java Application Let's prepare our environment for writing a simple client application. Also, as we're using JNDI, we need to have weblogic. They are quite different, and you should use the appropriate approach for your task. Consequently, these columns can participate in queries just like any other column type. You can read more about this approach and see examples in the WebLogic Server documentation on the Oracle driver, or on the Oracle Technology Network.

In this article we are going to focus exclusively on the XSU approach. Here is the complete source code oraxml. Lines 13 and 20 establish and close the connection. The most interesting lines are which make a so-called "XML query".

Line 14 initializes the query. Lines set the structure of the future XML document. Line 15 sets the maximum number of rows returned, limited to maxRows. Lines 16 and 17 set the root element of the document and the item delimiters. Line 18 generates an XML document and stores it in the xmlString variable.

As you can see, the code is very simple and easy to read.

SQL vs. XML in a database world -- GCN

Note that this is not production code. You should close a connection in a finally clause. We should not forget about JNDI, which we're using in this code. As this is a stand-alone Java application, we need to set a naming provider for it to use. We'll use our WebLogic Server; to configure this we need to create a jndi. Here is our jndi. As you can see, this is quite a handy utility that can be used for performing SQL queries and returning an XML formatted output.

However, XSU is not limited only to this functionality. XSU can also store them in relational tables by creating object views over the flat tables and querying over these views.


In addition, it supports XML attributes during generation. One of the questions you may be asking yourself is why we are using XML here and why we are calling it "a bridge.

XML as a Bridge between SQL and Web Applications

Imagine you've got an information portal, which is designed to deliver news from the SQL database to end users, whoever they are: Furthermore, you, as an information owner, can resell it to other end users, and your news should be shown with different titles, like "News from the Acme, Corp. But the news that you are delivering does not change. So why should you perform extra coding for every kind of end user who may receive your news, when you technically need only change the "look and feel"?

Now you can see that you need some transparent bridge that can receive SQL on one side and produce different formats on the other. This bridge is XML. Your servlet makes a request to the database, receives XML output, and applies an XSL template to it, producing a page for an end user. So, you need to change only a design in XSL and nothing more.

No extra coding, no wasted time.