Programming Solution

QUES What is Data Storage - Definition Language? ANSWER: The storage structures and access methods used by database system are specified by a set of definition in a special type of DDL called data storage-definition language. QUE What is DML (Data Manipulation Language)? ANS This language that enable user to access or manipulate data as organised by appropriate data model. 1) Procedural DML or Low level: DML requires a user to specify what data are needed and how to get those data. 2 ) Non-Procedural DML or High level: DML requires a user to specify what data are needed without specifying how to get those data. QUES What is VDL (View Definition Language)? ANS It specifies user views and their mappings to the conceptual schema. QUES What is DML Compiler? ANS It translates DML statements in a query language into low-level instruction that the query evaluation engine can understand. QUES What is Query evaluation engine? ANS It executes low-level instruction generated by compile

Q What is trigger in DBMS A program in a database that gets called each time a row in a table is INSERTED UPDATED or DELETED. Triggers allow you to check that any changes are correct or to fill in missing information before it is commited. Triggers are normally written in PL/SQL or Java QUEST What is E-R model? ANSWER: This data model is based on real world that consists of basic objects called entities and of relationship among these objects. Entities are described in a database by a set of attributes. QUES What is Object Oriented model? ANS This model is based on collection of objects. An object contains values stored in instance variables with in the object. An object also contains bodies of code that operate on the object. These bodies of code are called methods. Objects that contain same types of values and the same methods are grouped together into classes. QUES What is an Entity? ANS It is a 'thing' in the real world with an independent existence. QUE What is an En

Ques What is database? ANSWER: A database is a logically coherent collection of data with some inherent meaning, representing some aspect of real world and which is designed, built and populated with data for a specific purpose. Ques Describe the three levels of data abstraction? Ans The are three levels of abstraction: 1) Physical level: The lowest level of abstraction describes how data are stored. 2) Logical level: The next higher level of abstraction, describes what data are stored in database and what relationship among those data. 3) View level: The highest level of abstraction describes only part of entire database. Ques What is the basic difference between DBMS and RDBM... Answer The difference in RDBMS and DBMS does not lie in the way tables and data are related to each other (ie. the Foreign Key relationship). dBase and MS Access are DBMS's which have foreign key relationships implemented. RDBMS is based on the concepts of Relational Set Theory in mathematics and h