MySQL | Vineeta Garg
MY SQL
VIVA QUESTIONS
1. What is DDL and DML?
DDL (Data Definition Language): All the commands which are used to create,
destroy, or restructure databases and tables come under this category. Examples
of DDL commands are - CREATE, DROP, ALTER.
DML (Data Manipulation Language): All the commands which are used to
manipulate data within tables come under this category. Examples of DML
commands are - INSERT, UPDATE, DELETE.
2. What is RDBMS?
RDBMS: A DBMS used to manage Relational Databases is called an RDBMS
(Relational Data Base Management System). Some popular RDBMS software
available are: Oracle, MySQL, Sybase, Ingress.
3. What is data inconsistency?
Data inconsistency occurs when same data present in two different tables does not
match.
4. What is a relation?
Relation/Table: A table refers to a two-dimensional representation of data
arranged in columns (also called fields or attributes) and rows (also called records
or tuples).
5. What is cardinality and degree?
Cardinality: Total number of rows in a table is called the cardinality of the table.
Arity/Degree: Total number of columns of a table is called the Degree of the
table.
6. What is the difference between primary key, candidate key and
alternate key?
Primary Key: The group of one or more columns used to uniquely identify each
row of a relation is called its Primary Key.
Candidate Key: A column or a group of columns which can be used as the
primary key of a relation is called a candidate key because it is one of the candidates
available to be the primary key of the relation.
Alternate Key: A candidate key of a table which is not made its primary key is
called its Alternate Key.
7. What is selection and projection?
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MY SQL
VIVA QUESTIONS
1. What is DDL and DML?
DDL (Data Definition Language): All the commands which are used to create,
destroy, or restructure databases and tables come under this category. Examples
of DDL commands are - CREATE, DROP, ALTER.
DML (Data Manipulation Language): All the commands which are used to
manipulate data within tables come under this category. Examples of DML
commands are - INSERT, UPDATE, DELETE.
2. What is RDBMS?
RDBMS: A DBMS used to manage Relational Databases is called an RDBMS
(Relational Data Base Management System). Some popular RDBMS software
available are: Oracle, MySQL, Sybase, Ingress.
3. What is data inconsistency?
Data inconsistency occurs when same data present in two different tables does not
match.
4. What is a relation?
Relation/Table: A table refers to a two-dimensional representation of data
arranged in columns (also called fields or attributes) and rows (also called records
or tuples).
5. What is cardinality and degree?
Cardinality: Total number of rows in a table is called the cardinality of the table.
Arity/Degree: Total number of columns of a table is called the Degree of the
table.
6. What is the difference between primary key, candidate key and
alternate key?
Primary Key: The group of one or more columns used to uniquely identify each
row of a relation is called its Primary Key.
Candidate Key: A column or a group of columns which can be used as the
primary key of a relation is called a candidate key because it is one of the candidates
available to be the primary key of the relation.
Alternate Key: A candidate key of a table which is not made its primary key is
called its Alternate Key.
7. What is selection and projection?
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