Basic Concepts and Terminology of Databases - Short Questions and Answers

Basic Concepts and Terminology of Databases - Short Questions and Answers. Find the most important and more conceptual short questions with answers of Computer, ICS Part 2 on the database management system (DBMS) for the interview and final examinations for all boards of Pakistan and entry test for admission in universities.

Chapter No.2: 

Basic Concepts & Terminology of Databases

Short Questions & Answers

Q.1: Differentiate between database field and record?

Answer:

Field:  A field is a single piece of information about an object. It consisting of one or more characters e.g. student_id and student_name are the fields of the student. A field is also known as a column, data element, attribute, or data item.

Record: A collection of related data items treated as a single unit is called a record. A record is also known as row, tuple, or occurrence.

 

Q.2: What is a file?

Answer:

A collection of related records treated as a single unit is called a file. A file is also termed as data set, table, or relation.

 

Q.3: What is a database?

Answer:

The collection of tables with some traditional files and some other necessary data objects is termed as a database. Crickinfo, NADRA, and inventory systems for shopping malls are examples of database applications.

 

Q.4: What are the properties of a relation?

Answer:

A relation or a table which is the basis of a Relational Database Management System (RDBMS), by definition, must have certain inherent characteristics that form the basis for its underlying strength and flexibility.

Following are the properties of the relation/table:

• No duplicate rows exist

• The order of rows is insignificant

• The order of columns is insignificant

• Columns/attributes are all elemental atomic 

 

Q.5: What are the views?

Answer:

Views are created by using SQL (Structured Query Language). The purpose of using views purely to keep the data safe and secure from unauthorized and illegal users. The views provide the descriptions of relations that are not stored but constructed as needed from stored relations.  

 

Q.6: What is SQL?

Answer:

SQL (Structured Query Language) is a powerful database language used for data definition and data manipulation purposes, e.g., relations & views creation, records insertion, and data retrieving from the relations by using SQL commands.

 

Q.7: What are the indexes?

Answer:

Indexes are the tables created by the DBA containing the key attributes of the table for which the index is created. The importance associations defined in the system make use of this. It helps the system run smoothly and fast.

It has a very vital role in the Database Management Systems (DBMS), especially in Relational Database Management Systems (RDBMS).

 

Q.8: What is a key?

Answer:

A key is a single or combination of one or more fields and its purpose is to point/retrieve the data from the tables, according to the requirement. Keys are defined in the tables to access or sequence the stored data fast and smooth or to create the links between them.

Following are the types of keys:

• Primary Key
• Secondary Key
• Candidate Key / Alternate Key
• Composite / Concatenate Key
• Sort / Control Key
• Foreign Key

 

Q.9: What is a primary key?

Answer:

In relation, the attribute uniquely identifies a row or record. Student_Id is the attribute that uniquely identifies each student and thus can be used as a primary key.

 

Q.10: What is a secondary key?

Answer:

A secondary key is a non-unique field that is used as a secondary key. The secondary key is the key that has not been selected to be the primary key.

 

Q.11: What is the candidate key / alternate key?

Answer:

Sometimes, it is unclear which field to select as the primary key. There might exist some additional fields which also have the uniqueness property. These keys can be termed as candidate keys or alternate keys.

 

Q.12: What is the composite / concatenate key?

Answer:

These keys consist of two or more data elements or attributes. Invariably, these are the same as candidate keys except that of uniqueness requirement.

 

Q.13: What is a sort/control key?

Answer:

A sort/control key is used to physically sequence the stored data according to need. Multiple attributes can be used as sort fields.

 

Q.14: What is a foreign key?

Answer:

A foreign key is an attribute in a table whose value must match a primary key in another table. The table in which the foreign key is found is called a dependent table and to which it refers is called a parent table.

 

Q.15: Differentiate between parent and dependent (child) tables?

Answer:

The table in which the primary key is found is called as parent table and to which it refers is called as dependent (child) table.

Q.16: What is an entity?

Answer:

An entity is anything about which you want to keep information in the database. Student, teacher, and course_list are the examples of entities in Student Information System.  

 

Q.17: How to create a view in SQL?

Answer:

To create a view, the following SQL command is used:

CREATE VIEW     STUDENT_VIEW AS

SELECT              STUD_NO, STUD_NAME, STUD_ADDR

FROM                STUDENT

WHERE              STUD_GENER_CD = ”M”;

 

Q.18: Who is the user OR end user?

Answer:

The user or end-user is simply a person who uses the computers for his specific need. He might have a moderate knowledge of computers and IT. He does not need to know in-depth knowledge of the computer systems, but instead, he should be aware of the installed software he intends to use.

 

Q.19: Who is the Data Administrator (DA)?

Answer:

A data administrator (DA) is responsible for the entire data of an organization. He normally develops the overall functional requirements for the databases. He shares in developing the logical design for each database. Normally, the DA serves as a bridge between users and data processing staff.

 

Q.20: Who is the Database Administrator (DBA)?

Answer:

A database administrator (DBA) is responsible for the design, implementation, operation, management, and maintenance of the database. He must be technically expert on the overall workings/details of the database and DBMS. He is also responsible to make sure the database access rights, safeguard its security, maintain and fine-tune the database functionality.

➤ Basic Concepts & Terminology of Databases - MCQs
➤ Data Basics
➤ Database Design Process
➤ Getting Started with C
➤ Elements of C
➤ Input/Output
➤ Decision Constructs
➤ Loop Constructs
➤ Functions in C
➤ File Handling