dbms solved paper bca mdu rohtak

 

Que:-What is file system and DBMS?

A file system is a process that manages how and where data on a storage disk, typically a hard disk drive (HDD), is stored, accessed and managed. It is a logical disk component that manages a disk’s internal operations as it relates to a computer and is abstract to a human user.

DBMS

A database management system (DBMS) is system software for creating and managing databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data.

 

Que:-Name the five components of DBMS Environment and how they relate to each other?

DBMS have several components, each performing very significant tasks in the database management system environment. Below is a list of components within the database and its environment.

  • Software
  • Hardware
  • Data
  • Procedure
  • Database access language

Software
This is the set of programs used to control and manage the overall database. This includes the DBMS software itself, the Operating System, the network software being used to share the data among users, and the application programs used to access data in the DBMS.

Hardware
Consists of a set of physical electronic devices such as computers, I/O devices, storage devices, etc., this provides the interface between computers and the real world systems.

Data
DBMS exists to collect, store, process and access data, the most important component. The database contains both the actual or operational data and the metadata.

Procedures
These are the instructions and rules that assist on how to use the DBMS, and in designing and running the database, using documented procedures, to guide the users that operate and manage it.

Database Access Language
This is used to access the data to and from the database, to enter new data, update existing data, or retrieve required data from databases. The user writes a set of appropriate commands in a database access language, submits these to the DBMS, which then processes the data and generates and displays a set of results into a user readable form.

QUE :-3 What is mapping?  Why it is necessary in database architecture ?

data mapping is the process of creating data element mappings between two distinct data models. Data mapping is used as a first step for a wide variety of data integration tasks, including: Data transformation or data mediation between a data source and a destination.

 

QUE:-4 Record based and object based data models?

Record based

Record based Data Models. These data models are based on application and user levels of data. They are modeled considering the logical structure of the objects in the database. This data models defines the actual relationship between the data in the entities.

Object based

Object based Data Models are based on above concept. It is designed using the entities in the real world, attributes of each entity and their relationship. … There are two types of object based data Models– Entity Relationship Model and Object oriented data model.

Que:- What is degree relationship? Give an example?

The degree of relationship (also known as cardinality) is the number of occurrences in one entity which are associated (or linked) to the number of occurrences in another. There are three degrees of relationship.

For example- one-to-one (1:1) relationship

Que 5:- Discuss the properties of relation?

database relation simply refers to an individual table in a relational database. In a relational database, the table is a relation because it stores the relation between data in its column-row format. The columns are the table’s attributes, while the rows represent the data records.

Que 5:- Show the relational database is in BCNF then it is also in 3NF?

Boyce-Codd Normal Form (BCNF) is one of the forms of database normalization. A database table is in BCNF if and only if there are no non-trivial functional dependencies of attributes on anything other than a superset of a candidate key.BCNF is also sometimes referred to as 3.5NF

Que 6:- What is query processing? What are the typical phase of query processing ?

Query:- A database query can be either a select query or an action query. A select query is a data retrieval query, while an action query asks for additional operations on the data, such as insertion, updating or deletion.

Query Processing:-

  • Query Processing is a translation of high-level queries into low-level expression.

Annotation phase

Query rewrite phase  

Optimization phase

Execution phase

Author: Team onlinestudy.guru

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