OracleByAjay

  Capgemini - Oracle training at  Chennai Freshers intake 2018 Introduction to Relational algebra & Relational calculus In this guide, we will discuss what is  Relational algebra and relational calculus  and why we use these concepts. In the previous tutorials, we discussed the designing of database using  Relational model ,  E-R diagram  and  normalization . Now that we have designed the database, we need to store and retrieve data from the database, for this purpose we need to understand the concept of Relational algebra and relational calculus. Let’s start with the basics. Query Language In simple words, a Language which is used to store and retrieve data from database is known as query language. For example –  SQL There are two types of query language: 1.Procedural Query language 2.Non-procedural query language 1. Procedural Query language: In procedural query language, user instructs the system to perform a series of operations to pr...

Oracle Freshers training , Cognizant - Calcutta Active Database An active Database is a database consisting of a set of triggers. These databases are very difficult to be maintained because of the complexity that arises in understanding the effect of these triggers. In such database, DBMS initially verifies whether the particular trigger specified in the statement that modifies the database is activated or not, prior to executing the statement. If the trigger is active then DBMS executes the condition part and then executes the action part only if the specified condition is evaluated to true. It is possible to activate more than one trigger within a single statement. In such situation, DBMS processes each of the trigger randomly. The execution of an action part of a trigger may either activate other triggers or the same trigger that Initialized this action. Such types of trigger that activates itself is called as ‘recursive trigger’. The DBMS executes such chains of trigger in some pre...

Oracle training at Goldman Sachs, Banglore.     DATABASE MANAGEMENT SYSTEMS     UNIT II: Relational Model & Basic SQL   s: Relational Model: Introduction to relational model, concepts of domain, attribute, tuple, relation, importance of null values, constraints (Domain, Key constraints, integrity constraints) and their importance BASIC SQL: Simple Database schema, data types, table definitions (create, alter), different DML operations (insert, delete, update), basic SQL querying (select and project) using where clause, arithmetic & logical operations, SQL functions (Date and Time, Numeric, String conversion).   Objectives: After studying this unit, you will be able to: l     Describe Relational model l     Describe SQL and data types l     Explain the basic structures of SQL queries l     Know how to create tables l     Realise a...