Ycp's Ait

What is Oracle table?

A table is the basic unit of data storage in an Oracle database. The tables of a database hold all of the user accessible data. Table data is stored in rows and columns.

What are the various types of queries?

The types of queries are :
Normal Queries
Sub Queries
Co-related queries
Nested queries
Compound queries

Compare and contrast TRUNCATE and DELETE for a table?

Both the truncate and delete command have the desired outcome of getting rid of all the rows in a table. The difference between the two is that the truncate command is a DDL operation and just moves the high water mark and produces a now rollback. The delete command, on the other hand, is a DML operation, which will produce a rollback and thus take longer to complete.

What are different Oracle database objects?

TABLES
VIEWS
INDEXES
SYNONYMS
SEQUENCES
TABLESPACES

What is schema?

A schema is collection of database objects of a user.

Define a view?

A view is a virtual table which is based on the one or more physical tables and views.

When do you use WHERE clause and when do you use HAVING clause?

The WHERE condition lets you restrict the rows selected to those that satisfy one or more conditions.Use the HAVING clause to restrict the groups of returned rows to those groups for which the specified condition is TRUE.

What are the differences between stored procedures and triggers?

A stored procedures are compiled collection of programs or SQL statements that live in the database. A stored procedure can access and modify data present in many tables. Also a stored procedure is not associated with any particular database object. But triggers are event-driven special procedures which are attached to a specific database object.

what is trigger?

Triggers are special kind of stored procedures that get executed automatically when an INSERT, UPDATE or DELETE operation takes place on a table.

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

12 triggers

What are various types of joins?

Equi joins
Non-Equi joins *
Cartesian joins(also known as Cross joins)*
Self join
Outer join