What are ODL and OQL? Provide

ANSWERS :

ODL : (Object Description Language) It has arelational design. They are basicallydescription commands like CREATEin an SQL table. It is a language that is used to definethe object i.e their characteristics, properties andfunctions.

Example : it includes class , elementsand methods declaration. Let’s take an example of aschool.

interface name {

attribute integer classid;

attribute Struct student::Addr location;

relationships Set<Section> section- granted;

relationship Set <student> patrons inverse student:: hasaccount-at;

key(classid);

}

OQL : (Object Query Language) It is a standardfor query languages for an object oriented modelin SQL. It is very complex andtherefore is not usually completely implemented.It is a basis for many new query languages thatare present.

Example : There are different example fordifferent functions to perform –

* To select string of 50 ormore 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 namedesc;

* 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 adatabase that is used to store python objects .Ithas a single dictionary or object.Features : it provides high transparency.Capacity: It has a capacity to store high data inpython that is very reliable.

2. Object Store : It is a type of NoSQLdatabase which handles data that is created byapplications that uses OOP technology. It is usedby C++ language. Features : provide hightransparency. Capacity : capable of storing C++objects .

3. Versant : In this the data is storedtransactionally. It stores C++, Java and .NET objects andalso performs multithreading. Features : providestransparent data. Capacity : capable of storingC++, java and . Net object.

4. Object DB : It helps in directstoring of graphs of the objects. It reduces the time andthus improves the productivity. It is the mostreliable 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 storedin the form of entities in a table form wherease inOODBMS products the data is stored in the form ofobjects.

2. RDBMS products handles the simpledata whereas the OODBMS handle complexdata.

3. RDBMS products have a primarykey that is unique whereas in OODBMS has ObjectId.

4. RDBMS products have data independencewhereas in OODBMS products have dataencapsulation.