Oracle SQL in 10 Minutes - Asim Abbasi
CH1: SQL Basics | CH2:
SQL Operators |
CH3: SQL Built-in Functions | CH4:
SQL Joins | CH5:
UPDATE, INSERT & DELETE Statements |
CH6: CREATE, ALTER & DROP Statements | CH7:
Constraints | CH8:
Linking Tables vs Joining Tables | CH9:
SQL
Statements for Other Database Objects | CH10:
SQL Statements for
Database Security
Chapter 1: SQL Basics SQL is the language that we will use to communicate
with the Oracle Instance e.g. I am using “English” as a way of
communication because you understand it. Similarly to communicate with
Oracle Instance we use SQL (Seeqal). Before we proceed with the language
I want to clarify three terms that is used widely and sometimes few
people gets confused. These are SQL, PL/SQL and SQL*Plus. SQL as I
already told you is the language to communicate with Oracle Instance
whereas PL/SQL is the superset of SQL i.e. we use PL/SQL instead of SQL
when our target/goal requires multiple SQL commands to be executed based
on certain logic, event or condition then we take the benefit of this
language.
Figure 2: Three Important Terms. Next thing I would to discuss over here is few important concepts about
RDBMS or Relational Database Management System. There is a long old
history about “RDBMS standard”. It all started with Dr. E.F. Codd in
1969. Making a long story short there are lot other databases beside
Oracle that claim to be RDBMS e.g. MS SQL Server, MS Access, MySQL etc.
If I want to create my own database product named “Takveen” and if I
have big solid team of programmers; we all first have to read and
understand that RDBMS standard and then we can start writing the code
otherwise we cannot claim in the market that it’s a RDBMS database. Chapter 1: Overview
CH1: SQL Basics | CH2:
SQL Operators |
CH3: SQL Built-in Functions | CH4:
SQL Joins | CH5:
UPDATE, INSERT & DELETE Statements |
CH6: CREATE, ALTER & DROP Statements | CH7:
Constraints | CH8:
Linking Tables vs Joining Tables | CH9:
SQL
Statements for Other Database Objects | CH10:
SQL Statements for
Database Security Share with others:
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SQL*Plus is basically the environment where we write SQL or PL/SQL
commands. In other words it’s a front end tool we use to communicate
with Oracle Instance. There are lots of SQL front-end tools available
but it’s the one that gets installed once you install Oracle whether its
8i or 9i or 10g. In Oracle 9i and 10g they have introduced iSQL*Plus
which is a web-interface for executing SQL and PL/SQL code. If you are
good in programming you can develop one on your own using Visual Basic
or Visual C++ or even JAVA.
The way I categorize the RDBMS database products available in the market
keeping in mind their strength to handle data & handle concurrent user
requests is as follows.
Small Companies :: MS Access
Mid Size Companies :: MS SQL Server
Large Organization/Enterprise :: Oracle