1. Explain What is meant by Scrollable cursor?

A scrollable cursor, however, can move forward and backward, and can seek any desired record in the cursor. Such operations are common in applications that present results sets in scrolling windows. With a scrollable cursor, application developers do not need to create and manage their own buffer for the records.

2. Explain What is the output of SIGN function?

SIGN (a): Returns 1 if a is positive or if a is 0, and -1 if a is less than 0.

3. How to use SQL to build SQL, what is this called and give an example?

This is called dynamic SQL. An example would be:
set lines 90 pages 0 termout off feedback off verify off
spool drop_all.sql
select ?drop user ?||username||? cascade;? from dba_users
where username not in ("SYS?,?SYSTEM?);
spool off
Essentially you are looking to see that they know to include a command (in this case DROP USER...CASCADE;) and that you need to concatenate using the ?||? the values selected from the database.

4. Explain What is the maximum number of triggers, can apply to a single table?

Insert/Update/Delete :- 3
Before/After:- 2
Row Level/Statement Level:-2

Hence 3*2*2

5. Explain What is meant by SORTING and GROUPING?

For sorting we use order by clause in select statement. This is used to sort data in ascending order or descending order.
To group data based on perticulr column we use groupby clause.
Both are used to get distinct values.

6. Explain How do we eliminate the duplicate rows?

Use the DISTINCT keyword right after SELECT...

i.e. SELECT DISTINCT customername FROM customer

select * from emp e where rownum=
(select max(rownum) from emp ee
where e.empno=ee.empno)

7. Explain What is an Integrity Constraint?

Integrity constraint is a rule that restricts values to a column in a table.

8. Explain What is a Cartesian product?

A Cartesian product is the result of an unrestricted join of two or more tables. The result set of a three table Cartesian product will have x * y * z number of rows where x, y, z correspond to the number of rows in each table involved in the join.

9. Explain some PL/SQL Exceptions?






10. Explain What are the different types of SQL?

There are 5 types

1.data definition type

2.data manipulation

3.data control

4.transaction control

5.data query

SQL is Structured Query Language is a database computer language designed for managing data in relational database management systems (RDBMS).

PostgreSQL is an object-relational database management system (ORDBMS).It is released under a BSD-style license and is thus free software. As with many other open-source programs, PostgreSQL is not controlled by any single company, but has a global community of developers and companies to develop it.

SQLite is an ACID-compliant embedded relational database management system contained in a relatively small (~225 KB) C programming library. The source code for SQLite is in the public domain.

MySQL is a relational database management system (RDBMS) which has more than 6 million installations. MySQL stands for "My Structured Query Language". The program runs as a server providing multi-user access to a number of databases.

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