SQL-Developer-SOLYP_2.png' alt='Database Normalization Software' title='Database Normalization Software' />XML and Databases. Copyright 1. 99. 9 2. Ronald Bourret. Last updated September, 2. Introduction. This paper gives a high level overview of how to use XML with databases. It describes how the differences between data centric and document centric documents affect their usage with databases, how XML is commonly used with relational databases, and what native XML databases are and when to use them. NOTE Although the information discussed in this paper is mostly up to date, the idea that the world of XML and databases can be seen through the data centricdocument centric divide is somewhat dated. At the time this paper was originally written 1. XML databases, which were then not widely understood, even in the database community. However, it was always somewhat unrealistic, as many XML documents are not strictly data centric or document centric, but somewhere in between. So while the data centricdocument centric divide is a convenient starting point, it is better to understand the differences between XML enabled databases and native XML databases and to choose the appropriate database based on your processing needs. For a more modern look at the difference between XML enabled and native XML databases, see chapter 1 of XML for DB2 Information Integration. Is XML a Database Before we start talking about XML and databases, we need to answer a question that occurs to many people Is XML a databaseAn XML document is a database only in the strictest sense of the term. That is, it is a collection of data. In many ways, this makes it no different from any other file after all, all files contain data of some sort. As a database format, XML has some advantages. For example, it is self describing the markup describes the structure and type names of the data, although not the semantics, it is portable Unicode, and it can describe data in tree or graph structures. It also has some disadvantages. For example, it is verbose and access to the data is slow due to parsing and text conversion. Database Normalization Software' title='Database Normalization Software' />Learn relational database Design with practical concepts and examples. This series works with any database system Free Course. A database is an organized collection of data. A relational database, more restrictively, is a collection of schemas, tables, queries, reports, views, and other elements. Relational Database Normalisation Process Illogically or inconsistently stored data can cause a number of problems. In a relational database, a logical and efficient. In relational database design, the process of organizing data to minimize redundancy. Normalization usually involves dividing a database into two or more tables. Normalization helps in achieving resource optimization with improvements in MySQL database design. Learn about database normalization in MySQL. Hexen Full Version Windows there. Find out what normalization is and how your database can benefit from it or suffer from it. Learn the advantages, disadvantages, and some techniques and guidelines. By signing up you agree to our terms conditions. Objectoriented database model. This model defines a database as a collection of objects, or reusable software. Normalization in Database 1NF, 2NF, 3NF, BCNF, 4NF, 5NF, 6NF. Normalization is a database design technique which organizes tables in a manner that reduces redundancy. Normalization is the process of organizing data into a related table it also eliminates redundancy and increases the integrity which improves performance of the query. Accolades for Database Administration Ive forgotten how many times Ive recommended this book to people. Its well written, to the point, and covers the. Database Normalization Software' title='Database Normalization Software' />A more useful question to ask is whether XML and its surrounding technologies constitute a database in the looser sense of the term that is, a database management system DBMS. The answer to this question is, Sort of. On the plus side, XML provides many of the things found in databases storage XML documents, schemas DTDs, XML Schemas, RELAX NG, and so on, query languages XQuery, XPath, XQL, XML QL, QUILT, etc., programming interfaces SAX, DOM, JDOM, and so on. On the minus side, it lacks many of the things found in real databases efficient storage, indexes, security, transactions and data integrity, multi user access, triggers, queries across multiple documents, and so on. Thus, while it may be possible to use an XML document or documents as a database in environments with small amounts of data, few users, and modest performance requirements, this will fail in most production environments, which have many users, strict data integrity requirements, and the need for good performance. A good example of the type of database for which an XML document is suitable is an. It is much easier to invent a small XML language and write a SAX application for interpreting that language than it is to write a parser for comma delimited files. In addition, XML allows you to have nested entries, something that is harder to do in comma delimited files. However, this is hardly a database, since it is read and written linearly, and then only when the application is started and ended. Examples of more sophisticated data sets for which an XML document might be suitable as a database are personal contact lists names, phone numbers, addresses, etc., browser bookmarks, and descriptions of the MP3s youve stolen with the help of Napster. However, given the low price and ease of use of databases like d. BASE and Access, there seems little reason to use an XML document as a database even in these cases. The only real advantage of XML is that the data is portable, and this is less of an advantage than it seems due to the widespread availability of tools for serializing databases as XML. Why Use a Database The first question you need to ask yourself when you start thinking about XML and databases is why you want to use a database in the first place. Do you have legacy data you want to exposeAre you looking for a place to store your Web pages Is the database used by an e commerce application in which XML is used as a data transportThe answers to these questions will strongly influence your choice of database and middleware if any, as well as how you use that database. For example, suppose you have an e commerce application that uses XML as a data transport. It is a good bet that your data has a highly regular structure and is used by non XML applications. Furthermore, things like entities and the encodings used by XML documents probably arent important to you after all, you are interested in the data, not how it is stored in an XML document. In this case, youll probably need a relational database and software to transfer the data between XML documents and the database. If your applications are object oriented, you might even want a system that can store those objects in the database or serialize them as XML. On the other hand, suppose you have a Web site built from a number of prose oriented XML documents. Not only do you want to manage the site, you would like to provide a way for users to search its contents. Your documents are likely to have a less regular structure and things such as entity usage are probably important to you because they are a fundamental part of how your documents are structured. In this case, you might want a product like a native XML database or a content management system. This will allow you to preserve physical document structure, support document level transactions, and execute queries in an XML query language. Data versus Documents. Perhaps the most important factor in choosing a database is whether you are using the database to store data or documents. For example, is XML used simply as a data transport between the database and a possibly non XML application Or is its use integral, as in the case of XHTML and Doc. Book documents This is usually a matter of intent, but it is important because all data centric documents share a number of characteristics, as do all document centric documents, and these influence how XML is stored in the database. The next two sections examine these characteristics. Historical footnote I first heard the terms data centric and document centric on the xml dev mailing list. I dont know who coined them, but Ive found messages from 1. Data Centric Documents. Data centric documents are documents that use XML as a data transport. They are designed for machine consumption and the fact that XML is used at all is usually superfluous. That is, it is not important to the application or the database that the data is, for some length of time, stored in an XML document. Examples of data centric documents are sales orders, flight schedules, scientific data, and stock quotes. Data centric documents are characterized by fairly regular structure, fine grained data that is, the smallest independent unit of data is at the level of a PCDATA only element or an attribute, and little or no mixed content. The order in which sibling elements and PCDATA occurs is generally not significant, except when validating the document.