CT1 Answer Key
CT1 Answer Key
CT1 Answer Key
APART-A
1. Define DBMS
a. The lowest level of abstraction that describes how the data is stored is physical
level data abstraction.
b. The next higher level of abstraction that describes what data are stored in the
database and the relationship among those data is logical level data abstraction.
c. The highest level of abstraction describes only part of the entire database is view
level.
Schema: The overall design of the data base is called the data base schema.
Entity type: An entity type defines a collection of entities that have the same
attributes.
Entity set: The set of all entities of the same type is termed as an entity set.
Output:
Stu_Name Stu_Marks
Akhil 85
Chetan 95
Diksha 99
The ability to modify a schema definition in only level without affecting a Schema
definition in the next higher level is called data independence
9. Give the distinction between primary key, candidate key and super key.
Primary key – is used in a data base to avoid duplication of attributes and also
makes a relation to the other database.
Candidate key - a key which is in the data base is called as candidate key, it might
be any key attribute.
9.Give the distinction between primary key, candidate key and super key.
Primary key – is used in a data base to avoid duplication of attributes and also
makes a relation to the other database.
Candidate key - a key which is in the data base is called as candidate key, it might
be any key attribute.
It is the process of designating sub groupings within an entity set.It is a top down
process.
Specialization which is represented by triangle. The lable ISA stands for “is
a and represent, for eg that customer is a person.
PART-B
1.Query Processor: It interprets the requests (queries) received from end user
via an application program into instructions. It also executes the user request
which is received from the DML compiler.
Query Processor contains the following components –
DML Compiler: It processes the DML statements into low level instruction
(machine language), so that they can be executed.
DDL Interpreter: It processes the DDL statements into a set of table
containing meta data (data about data).
Embedded DML Pre-compiler: It processes DML statements embedded in
an application program into procedural calls.
Query Optimizer: It executes the instruction generated by DML Compiler.
2. Storage Manager: Storage Manager is a program that provides an interface
between the data stored in the database and the queries received. It is also
known as Database Control System. It maintains the consistency and integrity of
the database by applying the constraints and executing the DCL statements. It is
responsible for updating, storing, deleting, and retrieving data in the database.
It contains the following components –
Authorization Manager: It ensures role-based access control, i.e,. checks
whether the particular person is privileged to perform the requested operation
or not.
2. Hierarchical Model
In hierarchical model, data is organized into a tree like structure with each record is
having one parent record and
many children. The main drawback of this model is that, it can have only one to
many relationships between nodes.
There are two forms of SQL queries: embedded or static SQL and dynamic SQL. As a
result, we’ll be learning about these two varieties of SQL statements during this
blog.
Embedded SQL (or Static SQL): These are SQL statements that don’t change at
runtime and therefore can be hard coded into the application. As static SQL are fixed
queries, these statements will be analyzed and optimized and don’t require specific
Dynamic SQL: These are SQL statements that are constructed at runtime; for
example, the application that allows users to enter their own queries. Dynamic SQL
might have more permissions and security handling and a malicious user can create
Dynamic SQL enables you to make SQL statements dynamically at runtime. this
enables you to make more general purpose, flexible applications because the
Using Static SQL has its own benefits too, one in all them being the optimization of
the statement that ends up in an application with high performance because it offers
Coordinator