This article today discuss SQL Interview Questions
& Answers for the developer. SQL is important to the software development
you can use a software backend SQL server using today discuss a SQL
Interview Questions. The SQL server is storage and manipulation of data.
Databases. for more information clik this link SQL Interview Questions & Answers for developer https://www.guru99.com/sql-server-questions.html
what is SQL :
The database is a systematic collection of data.
Databases support storage and manipulation of data. Databases make data
management easy. This article provides SQL server interview questions for freshers
follow the SQL
server management Interview Questions.
1. What is DBMS?
A Database Management System (DBMS) is a
program that controls creation, maintenance and use of a database. DBMS can be
termed as File Manager that manages data in a database rather than saving it in
file systems.
2. What is RDBMS?
RDBMS stands for Relational Database
Management System. RDBMS store the data into the collection of tables, which is
related by common fields between the columns of the table. It also provides
relational operators to manipulate the data stored into the tables.
Example: SQL Server.
3. What is SQL?
SQL stands for Structured Query Language,
and it is used to communicate with the Database. This is a standard language
used to perform tasks such as retrieval, updating, insertion and deletion of
data from a database.
Standard SQL Commands are Select.
4. What is a Database?
Database is nothing but an organized form of
data for easy access, storing, retrieval and managing of data. This is also
known as structured form of data which can be accessed in many ways.
Example: School Management Database, Bank
Management Database.
5.What is View in SQL?
A View can be defined as a virtual table that
contains rows and columns with fields from one or more table.
Syntax : CREATE VIEW view_name AS SELECT
column_name ( s ) FROM table_name WHERE condition
6.What are triggers?
Triggers in SQL is kind of stored procedures
used to create a response to a specific action performed on the table such as
Insert, Update or Delete. You can invoke triggers explicitly on the table in
the database.
Action and Event are two main components of
SQL triggers when certain actions are performed the event occurs in response to
that action.
7. How we can update the view?
SQL CREATE and REPLACE can be used for
updating the view.
Following query syntax is to be executed to
update the created view
Syntax :
CREATE OR REPLACE VIEW view_name AS
SELECT
column_name ( s )
FROM table_name WHERE condition
8. Explain the working of SQL Privileges?
SQL GRANT and REVOKE commands are used to
implement privileges in SQL multiple user environments. The administrator of the database can grant
or revoke privileges to or from users of database object like SELECT, INSERT,
UPDATE, DELETE, ALL etc.
GRANT Command: This command is used provide database
access to user apart from an administrator.
9. How many types of Privileges are available in SQL?
There are two types of privileges used in
SQL, such as
System
Privilege: System privileges deal with an object of a particular type and
specifies the right to perform one or more actions on it which include Admin
allows a user to perform administrative tasks, ALTER ANY INDEX, ALTER ANY CACHE
GROUP CREATE/ALTER/DELETE TABLE, CREATE/ALTER/DELETE VIEW etc. Object Privilege: This allows to perform
actions on an object or object of another user(s) viz. table, view, indexes
etc. Some of the object privileges are EXECUTE, INSERT, UPDATE, DELETE, SELECT,
FLUSH, LOAD, INDEX, REFERENCES etc.
10. What is SQL Injection?
SQL Injection is a type of database attack
technique where malicious SQL statements are inserted into an entry field of
database such that once it is executed the database is opened for an attacker.
This technique is usually used for attacking Data-Driven Applications to have
an access to sensitive data and perform administrative tasks on databases.
For Example : SELECT column_name ( s ) FROM
table_name WHERE condition
11. What is the difference between SQL and PL/SQL?
SQL is a structured query language to create
and access databases whereas PL/SQL comes with procedural concepts of
programming languages.
12.What is the difference between SQL and MySQL?
SQL is a structured query language that is
used for manipulating and accessing the relational database, on the other hand,
MySQL itself is a relational database that uses SQL as the standard database
language.
13.What is the use of NVL function?
NVL function is used to convert the null
value to its actual value.
14. What is the Cartesian product of table?
The output of Cross Join is called as a
Cartesian product. It returns rows combining each row from the first table with
each row of the second table. For Example, if we join two tables having 15 and
20 columns the Cartesian product of two tables will be 15×20=300 Rows.
15. What do you mean by Subquery?
Query within another query is called as
Subquery. A subquery is called inner query which returns output that is to be
used by another query
16. How many row comparison operators are used while working with a subquery?
There are 3-row comparison operators which
are used in subqueries such as IN, ANY and ALL.
17. What is the difference between DELETE and TRUNCATE?
The
basic difference in both is DELETE is DML command and TRUNCATE is DDL DELETE is used to delete a specific row from
the table whereas TRUNCATE is used to remove all rows from the table We can use DELETE with WHERE clause but
cannot use TRUNCATE with it
18. What is the difference between DROP and TRUNCATE?
TRUNCATE removes all rows from the table
which cannot be retrieved back, DROP removes the entire table from the database
and it cannot be retrieved back.
19. What are Nested Triggers?
Triggers may implement data modification
logic by using INSERT, UPDATE, and DELETE statement. These triggers that
contain data modification logic and find other triggers for data modification
are called Nested Triggers.
20. What is Cursor?
A cursor is a database object which is used
to manipulate data in a row-to-row manner.
Cursor follows steps as given below
a.Declare Cursor
b.Open Cursor
c.Retrieve row from the Cursor
d.Process
the row Close Cursor
e.
Deallocate Cursor
21. What do we need to check in Database Testing?
Generally, in Database Testing following
thing is need to be tested
a. Database Connectivity
b. Constraint Check
c. Required Application Field and its size
d. Data Retrieval and Processing With DML
operations
e. Stored Procedures
f. Functional flow
22. What is Database White Box Testing?
Database White Box Testing involves
1.Database Consistency and ACID
properties
2.Database triggers and logical views
3.
Decision Coverage, Condition Coverage, and Statement Coverage
4. Database Tables, Data Model, and Database
Schema
5.Referential integrity rules
23. What is Database Black Box Testing?
Database Black Box Testing involves
1.Data Mapping
2.
Data stored and retrieved
3. Use of Black Box techniques such as
Equivalence Partitioning and Boundary Value Analysis (BVA)
24. What are Indexes in SQL?
The index can be defined as the way to
retrieve the data more quickly. We can define indexes using CREATE statements.
Syntax :
CREATE INDEX index_name ON table_name (
column_name )
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