WorksheetsIntroduction to Database Management Systems
Total questions: 32
Worksheet time: 41mins
What is the need of DBMS?
What are the disadvantages in file systems?
What are the integrity problems in database systems?
What are the atomicity problems in conventional file processing systems?
What are the security problems in database systems?
What is a Database Management System (DBMS)?
What are the characteristics of a database?
What are the views of data in a database?
What describes the physical structure of the database?
Internal or Physical level
Conceptual or Logical level
External or View level
What describes the structure of the whole database for a community of users?
Internal or Physical level
Conceptual or Logical level
External or View level
What includes a number of external schemas or user views?
Internal or Physical level
Conceptual or Logical level
External or View level
What is the transformation of requests and results from one level to another called?
Mapping
Schema
Data Independence
What is the logical structure of the database?
Schema
Instance
Data Independence
What is the ability to change a schema at one level without affecting the higher level schemas called?
Data Independence
Mapping
Schema
What is the ability to modify the physical or internal schema without changing the logical or external schemas?
Physical Data Independence
Logical Data Independence
What is the ability to modify logical or conceptual schema without changing the external schemas or application programs?
Physical Data Independence
Logical Data Independence
What is a collection of concepts that can be used to describe the structure of a database?
Data Model
Schema
Instance
What uses a collection of tables to represent both data and relationships among the data?
Relational model
Entity-Relationship data model
Object-based data models
What models an enterprise as a collection of entities and relationships?
Relational model
Entity-Relationship data model
Object-based data models
What is defined by the WWW Consortium (W3C) and was originally intended as a document markup language?
XML
JSON
HTML
In the hierarchical model, how is data organized?
As an inverted tree
In a graph
In two-dimensional tables
In the network model, how are entities organized?
As an inverted tree
In a graph
In two-dimensional tables
What are Keys?
A DBMS key is an attribute or set of an attribute which helps you to identify a row(tuple) in a relation(table).
Keys help you uniquely identify a row in a table by a combination of one or more columns in that table.
They allow you to find the relation between two tables.
All of the above.
What is the Super key?
A superkey is a group of single or multiple keys which identifies rows in a table.
A super key may have additional attributes that are not needed for unique identification.
Both A and B.
None of the above.
What is a Primary Key?
A column or group of columns in a table which helps us to uniquely identifies every row in that table.
The primary key can't be a duplicate.
The same value can't appear more than once in the table.
All of the above.
What is the Alternate key?
All the keys which are not primary key are called an alternate key.
It is a candidate key which is currently not the primary key.
A table may have single or multiple choices for the primary key.
All of the above.
What is a Candidate Key?
A super key with no repeated attribute is called candidate key.
The Primary key should be selected from the candidate keys.
Every table must have at least a single candidate key.
All of the above.
What is the Foreign key?
A foreign key is a column which is added to create a relationship with another table.
Foreign keys help us to maintain data integrity.
Every relationship in the model needs to be supported by a foreign key.
All of the above.
What is the Compound key?
Compound key has many fields which allow you to uniquely recognize a specific record.
Each column may not be unique by itself within the database.
The combination of composite keys become unique.
All of the above.
What is the Composite key?
A key which has multiple attributes to uniquely identify rows in a table.
Any part of the compound key can be a foreign key.
The composite key may or may not be a part of the foreign key.
All of the above.
Find all the tuples in which the amount lent is more than 1200 in loan relation.
List all the loan-numbers and amount of the loan.
