Database Interview Questions

Youre using a Sub-query -- [(select dname from dept where deptno = e.deptno)] -- to get around using a join clause like -- [FROM EMP E INNER JOIN DEPT D ON (D.DEPTNO = E.DEPTNO)] -- however, you are n...

SQL coins the term query as the name for its commands. Basically, all SQL code is written in the form of a query statement and then executed against a database. All SQL queries perform some type of da...

There are 3 rules to enforce table level integrity. 1.Foreign key value can be modified only if we want to match the corresponding primary key value. 2.We cannot delete records either from parent or c...

The Exception section of the PL/SQL block contains the functions for error handling.

Three activities involved in requirement gathering are
1.Eliciting requirement
2.Analyzing requirement
3.Recording requirement

The trigger which can be fired on DDL operator is DDL trigger.

Microsoft SQL Server have some more additions to Database Standard Query Language (SQL) is called T-SQL

SQL is the Structured Query Language. it is developed by IBM.
TSQL is the Transact SQL. it is implementation of the SQL server. it is developed by Microsoft.
TSQL is used in writing the procedure and some advanced concepts are written by this.

view is called a temporarily table when we want to create the copy of any table as requirement column then we use the view

syntax-------------
create view (view name) as select (* or column name) from (table name);

A view is a virtual table, which provides access to a subset of columns from one or more tables. It is a query stored as an object in the database, which does not have its own data.

there are two type of join

1)inner join
inner join have a three type
I)equi join
II)nonequi join
III)self join

and outer join have a two type

I)right outer join
II)left outer join

and one is a ANSI join that a advance

Join,
Inner join,
Outer join,
Left join,
Right join,
Full join

entity relationship when attribute are connected to entity there are different different type attribute are available weak entity and strong entity when we are using key that called strong entity and when key are not connected that called weak entity

Weak Entity generally don't possess key attributes of their own whereas a Strong Entity possess its own key attributes that are independent of other entities. Weak entity is usually existence-dependent on another entity type and does not have enough attributes to form its own primary key.

DBMS is a when data are not stored in table and RDBMS is used to all data are stored in table and distributed database when more than one table are connected with each other so its is called a distributed database

DBMS - It’s a software package combination of various computer programs which can be used to control, administer, maintain and use of the database. RDBMS - Its a database management system (DBMS) b...

normal are of five type 1) 1 normal form 2) 2 normal form 3) 3 normal form 4) 4 normal form 5) 5 normal form all normal are created to connected a table with each other and data are retrieve very ea...

Database is a structured collection of relational data. Database is used to store the relational, network or hierarchical data. It contains some sort of data and it is being used by the organization...

In simple words, a database is used to store information, and a data warehouse is used to query and analyse the stored data in several ways. Data warehouse helps business management to take important...

Data Abstraction means suppression of information / details of data organization and storage. Data Abstraction gives importance to mainly essential aspects in order to help better understanding of th...

There are a couple of reasons that I can think of for this:(1)  The indexes that are created on a table occupy physical disc space, the more the number of indexes created, the more would be the s...

defragmentation is to make data take a small space in storing (to compress data) while re-og=rganization is to rebuild or rearrange the data

The store table and the customer table would not have any direct relation. Instead, both of them would be pointing to a transaction table which would contain the store id and the customer id.

Physical model
Logical model
View model