Question

1. What are ODL and OQL? Provide a comprehensive example for each.

2. Perform some research on the Internet on OODBMS products. Compare various OODBMSs currently on the market in terms of features, capacity, and scalability. How do they compare with RDBMS products?

Answer 1

ANSWERS :

ODL : (Object Description Language) It has a relational design. They are basically description commands like CREATE in an SQL table. It is a language that is used to define the object i.e their characteristics, properties and functions.

Example : it includes class , elements and methods declaration. Let's take an example of a school.

interface name {

attribute integer classid;

attribute Struct student::Addr location;

relationships Set<Section> section- granted;

relationship Set <student> patrons inverse student:: has account-at;

key(classid);

}

OQL : (Object Query Language) It is a standard for query languages for an object oriented model in SQL. It is very complex and therefore is not usually completely implemented. It is a basis for many new query languages that are present.

Example : There are different example for different functions to perform -

* To select string of 50 or more length

select a from java.lang.String a where a.value.length>=50

* Use of FROM clause :

SELECT p.age FROM t1 WHERE p.age>20;

* Use of GROUP BY :

SELECT name, class FROM tb1 WHERE class>10 GROUP BY name desc;

* To get integers of length 15 or more

select b from[P b where b.length >=15

* To find maximum marks

select name, age, marks FROM t WHERE t.marks =max

OODBMS currently available in market :

1. ZODB : ( Zope Object Database) It is a database that is used to store python objects .It has a single dictionary or object. Features : it provides high transparency. Capacity: It has a capacity to store high data in python that is very reliable.

2. Object Store : It is a type of NoSQL database which handles data that is created by applications that uses OOP technology. It is used by C++ language. Features : provide high transparency. Capacity : capable of storing C++ objects .

3. Versant : In this the data is stored transactionally. It stores C++, Java and .NET objects and also performs multithreading. Features : provides transparent data. Capacity : capable of storing C++, java and . Net object.

4. Object DB : It helps in direct storing of graphs of the objects. It reduces the time and thus improves the productivity. It is the most reliable software for Java database. Features : Improves productivity and also provides transparency. Capacity : high reliability for Java database.

Comparison with RDBMS products :

1. In RDBMS products the data is stored in the form of entities in a table form wherease in OODBMS products the data is stored in the form of objects.

2. RDBMS products handles the simple data whereas the OODBMS handle complex data.

3. RDBMS products have a primary key that is unique whereas in OODBMS has Object Id.

4. RDBMS products have data independence whereas in OODBMS products have data encapsulation.