BT0066-Database Management Systems

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FALL 2014 – Assignment

PROGRAM	B.Sc IT
SEMESTER	FIRST
SUBJECT CODE & NAME	BT0066-Database Management Systems
CREDIT	3
BK ID	B0950
MAX.MARKS	60

Note – Answer all questions. Each question is followed by evaluation scheme.

1 Explain the concept of data independence and explain why it is required?

Answer: – Data independence:- Data independence is the type of data transparency that matters for a centralized DBMS. It refers to the immunity of user applications to make changes in the definition and organization of data.

Physical data independence deals with hiding the details of the storage structure from user applications. The application should not be involved with these issues, since there is no difference in the operation carried out against the data. The data independence and operation independence together gives the feature of data abstraction. There are two

2 Draw and explain the diagram of SQL server 2000 architecture.

Answer:

Q.3 What do you mean by indexed sequential file organization? Explain with the help of an example.

Answer: – Indexed sequential file organization:-

An indexed file contains records ordered by a record key. Each record contains a field that contains the record key. The record key uniquely identifies the record and determines the sequence in which it is accessed with respect to other records. A record key for a record might be, for example, an employee number or an invoice number.
An indexed file can also use alternate indexes, that is, record keys that let you access the file using a different logical arrangement

Q.4 What is the system catalog in RDBMS? Also explain what information is stored in the system catalog.

Answer:- system catalog in RDBMS: The database catalog of a database instance consists of metadata in which definitions of database objects such as base tables, views (virtual tables), synonyms, value ranges, indexes, users, and user groups are stored.[1][2]

The SQL standard specifies a uniform means to access the catalog, called the INFORMATION_SCHEMA, but not all databases follow this, even if they implement other aspects of the SQL standard. For an example of database-specific metadata access methods,

Q.5 What do you mean by semantics of TRC queries? Give an example of TRC queries.

Answer:- semantics of TRC queries:- Tuple calculus is a calculus that was introduced by Edgar F. Codd as part of the relational model, in order to provide a declarative database-query language for this data model. It formed the inspiration for the database-query languages QUEL and SQL, of which the latter, although far less faithful to the original relational model and calculus, is now the de-facto-standard database-query language; a dialect of SQL is used by nearly every relational-database-management system. Lacroix and Pirotte proposed domain calculus, which is closer to first-order logic and which showed that both of these calculi (as well as relational

6 Explain BCNF with an example.

Answer : Boyce-Codd Normal Form (BCNF)

When a relation has more than one candidate key, anomalies may result even though the relation is in 3NF.
3NF does not deal satisfactorily with the case of a relation with overlapping candidate keys
i.e. composite candidate keys with at least one attribute in common.
BCNF is based on the concept of a determinant.