OODB and XML Database Management Systems Fall 2012

OODB and XML Database Management Systems – Fall 2012 Company. Matthew LOGO Moccaro

Outline 1. OODB 2. OODB AND SQL 3. XML 4. XML Queries

Object Databases

Object Databases A History • First arrived in the 1980 s and 1990 s • Use objects to represent data with a set of attributes. • Developed due to certain limitations of the very popular relational model. Ø Let’s take a look at an example of one of these limitations.

Limitations Example: Part 1 SSN Name Phone. N Child 111 -22 -3333 Joe Public 516 -123 -4567 222 -33 -4444 111 -22 -3333 Joe Public 516 -345 -6789 222 -33 -4444 111 -22 -3333 Joe Public 516 -123 -4567 333 -44 -5555 111 -22 -3333 Joe Public 516 -345 -6789 333 -44 -5555 222 -33 -4444 Bob Public 212 -987 -6543 444 -55 -6666 222 -33 -4444 Bob Public 212 -987 -1111 555 -66 -7777 222 -33 -4444 Bob Public 212 -987 -6543 555 -66 -7777 222 -33 -4444 Bob Public 212 -987 -1111 444 -55 -6666

Limitations Example: Part 2 SSN Name Phone. N Child 111 -22 -3333 Joe Public 516 -123 -4567 222 -33 -4444 111 -22 -3333 Joe Public 516 -345 -6789 222 -33 -4444 111 -22 -3333 Joe Public 516 -123 -4567 333 -44 -5555 111 -22 -3333 Joe Public 516 -345 -6789 333 -44 -5555 222 -33 -4444 Bob Public 212 -987 -6543 444 -55 -6666 222 -33 -4444 Bob Public 212 -987 -1111 555 -66 -7777 222 -33 -4444 Bob Public 212 -987 -6543 555 -66 -7777 222 -33 -4444 Bob Public 212 -987 -1111 444 -55 -6666

Limitations Example: Part 3 Explanation • There are several ways around this problem, however, they normally lead to more difficulties. • More tables, more complex queries. Ø Our solution can be an OODB. To help explain an object database, let’s compare it to something we are familiar with, the relational model.

Object Vs. Relational: Part 1 Object Database Relational Database Contains Classes Contains Relations which are: Sets of Objects Sets of Tuples

Object Vs. Relational: Part 2 Object Database Relational Database Components of an object can be complex types. Components of a tuple must be primitive types. Sets, Tuples, Objects…. . Strings, Integers…

Object Vs. Relational: Part 3 Object Database • Objects can have inheritance. • Objects can have methods. • Can be all in the same language. Relational Database N/A

OODB The Conceptual Object Data Model TEXT • Helps us to understand OODB. • Let’s take a better look at: • Objects • Classes • Types

The Conceptual Object Data Model Objects TEXT • In this model, each object has an individual ID. • Called an “oid” • Different from a Primary Key • Cannot change for an object • Values • Can Change • Can be complex

The Conceptual Object Data Model Classes TEXT • Organizes similar objects • Class called Person contains objects with information regarding each person. • Classes Have: • Type • Method Signatures • Extent

The Conceptual Object Data Model Types TEXT • Types could be: • Basic • Reference • Tuple • Set • Subtype and Supertype TEXT

Object-Relational Database Object Relational Database Ø Combination of Object and Relational Databases • • Top Level Classes which contain tuples. These classes are called “relations. ” Ø Tuples are “tuple objects. ” • • Top level structure is always a tuple. Can have complex values.

Object Databases and SQL

Object Databases A History • First added to SQL in SQL: 1999 • Created with backwards compatibility in mind. • SQL-92 • Remained in SQL: 2003, SQL: 2008, and SQL: 2011.

Row Type A New Type • To create a tuple type in SQL, we can now use the row keyword: CREATE TABLE Person( Name CHAR(20), Address ROW(Number INTEGER, STREET CHAR(20), ZIP CHAR(5))) To insert new values: INSERT INTO Person(Name, Address) VALUES (‘John Doe’, ROW(666, ‘Hollow Rd. ’, ‘ 66666’))

Creating Objects Creating A Type • To create an object in SQL, we need to go through a few steps. 1. First we can define a type. CREATE TYPE Student. Type AS( Address ROW(Number INTEGER, STREET CHAR(20), ZIP CHAR(5))) Id INTEGER, Status CHAR(2));

Creating Objects Creating A Table 2. Next, we can create a new table from our type. CREATE TABLE Student OF Student. Type; SQL regards the rows of a table declared in this way as objects. The book introduces many other new concepts in this area.

XML

XML A History • XML was first developed in the late 1990 s and came into popularity soon after. • EXtensible Markup Language • HTML displays data, XML carries data • File Extension is. xml Ø Let’s create a file….

XML Example First, we can start by making an XML declaration…. . <? xml version=“ 1. 0” encoding=“UTF-8” ? >

XML Example File Comments are done as <!-- Comment --> <? xml version=“ 1. 0” encoding=“UTF-8” ? > <!- - Written By: Matt - - >

XML Example File Let’s make a menu. So we’ll declare some menu tags. This is called the root element. <? xml version=“ 1. 0” encoding=“UTF-8” ? > <!- - Written By: Matt - - > <menu> </menu> All elements must have an open and close tag. Close tags have a “/”

XML Example File Now let’s put an entrée section. <? xml version=“ 1. 0” encoding=“UTF-8” ? > <!- - Written By: Matt - - > <menu> <entree> </menu>

XML Example File Let’s add some details. How about a name? <? xml version=“ 1. 0” encoding=“UTF-8” ? > <!- - Written By: Matt - - > <menu> <entree> <name>Sunburnt Chicken</name> </entree> </menu>

XML Example File And a detail about this entrée. <? xml version=“ 1. 0” encoding=“UTF-8” ? > <!- - Written By: Matt - - > <menu> <entree> <name>Sunburnt Chicken</name> <fatgrams>23</fatgrams> </entree> </menu>

XML Example File Let’s add an entirely new entrée. <? xml version=“ 1. 0” encoding=“UTF-8” ? > <!- - Written By: Matt - - > <menu> <entree> <name>Sunburnt Chicken</name> <fatgrams>23</fatgrams> </entree> <name>Gusto Spaghetti</name> <fatgrams>55</fatgrams> </entree> </menu>

XML Example File Attributes can help make things more clear. We could do this…. <? xml version=“ 1. 0” encoding=“UTF-8” ? > <!- - Written By: Matt - - > <menu> <entrée 1> <name>Sunburnt Chicken</name> <fatgrams>23</fatgrams> </entrée 1> <entrée 2> <name>Gusto Spaghetti</name> <fatgrams>55</fatgrams> </entrée 2> </menu>

XML Example File But you can also add attributes within a tag. < tagname something = “value” > <? xml version=“ 1. 0” encoding=“UTF-8” ? > <!- - Written By: Matt - - > <menu> <entrée id = “ 1”> <name>Sunburnt Chicken</name> <fatgrams>23</fatgrams> </entrée> <entrée id = “ 2”> <name>Gusto Spaghetti</name> <fatgrams>55</fatgrams> </entrée> </menu>

XML • Can be formatted in several ways. • CSS • XSLT • Documents can be validated by: • XML Schemas • DTDs Ø Let’s take a look at some XML queries….

XML Queries

XML Queries DTD XSLT XML Schema XML XQuery XPath

XML Query Languages XPath XSLT XQuery Solutions for XML Queries

XPath • XML Query Language which views XML documents as trees. • Things such as comments and elements are nodes of these trees. • Allows us to traverse the tree and find a “path” to what we need. • Gives us an easy to understand language for querying XML Documents.

XSLT • XSL Transformation • • Files usually called stylesheets. Can be used to query and to format XML Includes conditional instructions…. More powerful query language which can utilize parts of XPath. • Certain queries such as joins can still be difficult in XSLT.

XQuery • Built by taking the best parts of two other query languages, XQL and XML-QL. • Still uses XPath as a syntax for its expressions. • More similar to SQL: FOR (variable declarations) WHERE (condition) RETURN (result)

SQL/XML • Slowly becoming part of the SQL standard. • Allows us to work directly with XML documents from SQL. • Many vendors such as Oracle, MS SQL Server, My. SQL, and Postgre. SQL already have much functionality built-in.

Summary 1. OODB Object Databases help us to excel where the relational model may be cumbersome. 2. OODB AND SQL Allow us to integrate objects into our databases while still utilizing SQL. 3. XML A highly customizable language which helps us to represent data almost universally. 4. XML Queries Gives us many different languages to use XML to its full potential.

The End Thank You!

References: Wagner, Richard and Richard Mansfield. XML for Dummies For Dummies. 2003. Kifer, Michael and Arthur Bernstein, and Philip M. Lewis Database Systems Boston: Pearson Education, 2006 XML Tutorial. W 3 Schools. 2012 Web. Nov. 2012 http: //www. w 3 schools. com/xml/ SQL/XML. Wikipedia. 2012 Web. Nov. 2012 http: //en. wikipedia. org/wiki/SQL/XML