DBMS Lab Manual

DBMS LAB MANUAL

The Structured Query Language (SQL) is a computer language for accessing and manipulating databases.

The fundamental concept is to think of the data as being stored in one or more tables. When a request is made to retrieve data from these tables, which is called a query, the resultant output is also presented in as table.

There are many different versions of the SQL language, but to be in compliance with the ANSI SQL '92 Standard, they must use and support the same major keywords in a similar manner (such as SELECT, UPDATE, DELETE, INSERT, WHERE, and others.

This manual is specially written for Students who are interested in understanding Structured Query Language and PL-SQL concepts in the Computer Engineering and Information technology field and wants to gain enhance knowledge about power of SQL Language in Relational Database Management System Development.

The manual covers practical point of view in all aspects of SQL and PL/SQL including DDL, DML,DCL sublanguages, also there are practices for Views, Group by, Having Clause. All PL-SQL concepts like Condition and Loop Structures, Functions and Procedures, Cursor, Triggers, Locks are illustrated using best examples.

Copyright © 2012 Jitendra Patel

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Every effort has been made to make this book as complete and as accurate as possible, but no warranty or fitness is implied. The information provided is on an as is basis. The authors and the publisher shall have neither liability nor responsibility to any person or entity with respect to any loss or damages arising from the information contained in this book.

Practical 1: Create synonyms, sequence and index.

Synonyms:

A synonym is an alias for a database object (table, view, procedure, function, package, sequence, etc.). Synonyms may be used to reference the original object in SQL as wel as PL/SQL.

They can be used to hide ownership and location of the database objects they refer to and minimize the impact of moving or renaming the database objects.

The syntax for creating a synonym is:

create [or replace] [public] synonym [schema .] synonym_name

for [schema .] object_name [@ dblink];

There are two types of synonyms:

·                     private

Private synonyms exist only in a specific user schema. The owner of the synonym maintains control over availability to other users.

·                     public

A public synonym is available to all users

For example:

create public synonym suppliers

for app.suppliers;

This first example