PL/SQL

Question 1

Basic LOOP

Answer 1

LOOP

EXIT WHEN

END LOOP

Question 2

For LOOP

Answer 2

FOR cont IN 1..100
LOOP

END LOOP

Question 3

While LOOP

Answer 3

WHILE
LOOP

END LOOP

Question 4

Compound queries, SET operators

Answer 4

UNION
UNION ALL
INTERSECT
MINUS

Question 5

JOIN tables

Answer 5

INNER

OUTER

Question 6

SQLERRM, come si usa?

Answer 6

Nelle eccezioni per stampare il messaggio di errore

Question 7

Qual’è la differenza tra INSTR e SUBSTR?

Answer 7

INSTR estrae l’indice di inizio della stringa ricercata

SUBSTR estrae la stringa

Question 8

Semijoin

Answer 8

Where exists

Question 9

Come gestire gli errori in pl/sql

Answer 9

DECLARE
...
BEGIN
...
EXCEPTION
WHEN exception1 THEN
...
WHEN exception2 THEN
...
WHEN others THEN
...
END;

Question 10

Cosa sono i Constraints

Answer 10

This is the most common Oracle Interview Questions asked in an interview. Constraints are the rules defined over data. Named constraint for a primary key can be added in two ways:
1. During table creation:
CREATE TABLE Employees (
Eid int NOT NULL,
Name varchar(255) NOT NULL,
Salary number(8),
Age int,
CONSTRAINT PK_ID PRIMARY KEY (Eid)
);

2. In the Alter statement
   ALTER TABLE Employees
   ADD CONSTRAINT PK_ID PRIMARY KEY (Eid);

Question 11

Null in equality expression

Answer 11

Si usa IS NULL e non

= NULL

Question 12

Nested table

Answer 12

Specifico data type che contiene record di una tabella

Question 13

VARRAY

Answer 13

Varray

Question 14

Operatore q[]

Answer 14

Q[]

Question 15

Tipi di istruzioni SQL

Answer 15

The five types of SQL statements are:

Data Definition Language (DDL): CREATE, DROP, RENAME, ALTER, TRUNCATE

Data Manipulation Language (DML): INSERT, DELETE, UPDATE, MERGE

Data Control Language (DCL): GRANT, REVOKE

Data Retrieval: SELECT

Transaction Control Statements: COMMIT, SAVEPOINT, ROLLBACK

Question 16

Null in query

Answer 16

https: //www.toptal.com/sql/interview-questions
https: //asktom.oracle.com/pls/apex/asktom.search?tag=not-in-operator-with-null-data

Question 17

Sql%rowcount

Answer 17

Come si usa