Q1. What is the difference between foreign key and reference key? Answer. A Foreign key is the key which refers to another table’s primary key.A Reference key is the primary key of table referred by another table. Q2. Differentiate between Primary key and Unique Key Answer. Primary key and Unique key both enforces uniqueness ofContinue reading “Indexes”
Tag Archives: Query
Tables & External Tables
Q1. What are the various constraints that can be applied to a Table? Answer. NULL, NOT NULL, CHECK, DEFAULT, Primary Key & Foreign Key. Q2. What is the purpose of a CLUSTER? Answer. Oracle does not allow a user to specifically locate tables, since that is a part of the function of the RDBMS. However,Continue reading “Tables & External Tables”
General SQL & PL/SQL
Q1. Difference between DBMS & RDBMS Answer. DBMS RDBMS Data is stored in form of files. Data is stored in form of tables. Normalization is not applied. Normalization is applied. Relations between different data is not set as data is stored in form of files. Relationship between tables can be set as data is storedContinue reading “General SQL & PL/SQL”
Written Test Questions
Q1. From the following SQL Statements which one is the most reliable? Answer. E] is the most reliable statement. Q2. From the following statements which one will you prefer to use & why? Answer. B] as select will consume more time than PL/SQL code. Q3. Which relational operators in where clause results in non-usage ofContinue reading “Written Test Questions”
TechOraFAQ 