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In the 1970s, a U.S. government agency wanted a database program which would be fast in retrieving data stored, since the database program which was in existence then, was only capable of retrieving data after several hours that the database was queried especially in an agency where very large amount of data was stored.

Three software developers by name; Larry Ellison (current CEO of Oracle Corporation), Bob Miner and Ed Oats who had a software company decided to embark on this project. They came up with a Database Management System (DBMS) that could retrieve data from a large data bank (database) within seconds. Thus they named it Oracle. Why Oracle? Because, an Oracle is something you can consult which gives you your answers immediately. A DBMS is a software used for the proper storage and management of data (information).
Oracle is an Object Relational Database Management System (ORDBMS).

Well, before the lesson starts sounding Greek, let's first know what a database is. A database has several meanings depending on what it is used for, but I will simply say that it is an ordered collection of data, ordinarily stored in one or more associated files. The data is stored in various tables whereby a piece of data in one table will be referencing (referring to or relying on) data in another thus making them have relations with each other. By the reason of this relation, we say that the Database is a Relational Database (an RDBMS). We also have ORDBMS. The basic difference between an RDBMS and an ORDBMS is that data are well structured (arranged) in tables in an RDBMS while and ORDBMS stores data also in tables but can also store free-standing objects without having to arrange them in tables.

A Table consists of Rows (horizontally) and Columns (vertically). A row is a set of data about a person or anything, while a column keeps a particular type of record for every row under it.
As important as the database, is the Structured Query Language (SQL). It is professionally pronounced ‘sequel’. Have you thought of this? How is data, which has been inputted into the database retrieved? The retrieval of data/information is done with the use of the SQL. This process of retrieval is called ‘querying’. The SQL is a standard language understood by the database. Its statement or command tells the database, the information you want to retrieve or input, in what way, from where (that is, from which table) and in what order, as the case maybe.

We will talk about various SQL statements which include the Data Manipulation Languages (DML – and these are INSERT, UPDATE, DELETE and MERGE), the Data Definition Languages (DDL – these are CREATE, ALTER, DROP, RENAME and TRUNCATE), the Data Control Languages (DCL - these are GRANT and REVOKE) and the Transaction Control Statements (these are COMMIT, ROLLBACK and SAVEPOINT).

Data types study is also an important aspect of the database. Since a table is the basic unit of storage, it is divided into columns. For instance, there must be a column under where all surnames will be entered and others where dates and account numbers are entered. A data type is an attribute which is set on every column, enforcing the type of data that can be stored under such column. It makes it impossible for a user (that is, you) to enter numbers (digits) in a column that is meant to contain only characters such as the surnames. The basic data types we will be dealing with include: CHAR, VARCHAR2, DATE, NUMBER and TIMESTAMP. There are several others. Since all RDBMSs are required to support a minimum number of database objects in order to comply with the basic requirements for a relational database, Oracle supports several objects. Some of the basic database objects include TABLES, VIEWS, SYNONYMS, SEQUENCIES, INDEXES, TRIGGERS, PROCEDURES (named and anonymous blocks), FUNCTIONS, PACKAGES, etc. Since the database contains (is made up of) several objects as named above, information about them needs to be stored. This is done by the Data Dictionary, which in any database contains metadata information. Metadata means ‘data about data’. The Data Dictionary is a set of tables (also called base tables) that keep information about that database itself. These base tables are always only accessible to an Oracle user named SYS. Both this user (SYS) and the Data Dictionary are created during the creation of the database. To make it easier to access that data dictionary and get information on objects in the database, a series of views are created during the database creation process. These views are commonly referred to as Data Dictionary views. Oracle has 3 sets of data dictionary views:

- USER_name of the view : these allow users to get information on objects that are in their schema (i.e. objects that they have created and own)
- ALL_name of the view : these allow users to get information on objects that they own or have been given access to within the database, even if those objects were not created by them or within their schema
- DBA_name of the view : these are designed to be used by the database administrator of the database. They provide a full set of information for objects in the database e.g. access to any object created or owned by any user

In the course of our lessons, we will learn some PL/SQL (Procedural Language/Structured Query Language). This is basically for the Oracle Developers, but is necessary for DBAs in order to be able to perfectly tell the developer, the type of code you want him or her to write. PL/SQL is an extension of SQL which grants automated functionality to the operation of a SQL.

Briefly, the responsibilities of a database administrator includes, but not limited to the following:
- Sizing and evaluation of a server hardware
- Installation of Oracle Software
- Plan and Design a Database structure
- Create Databases
- Backup databases and implement other ways to protect data
- Create and maintain database users
- Implement applications and database designs
- Restore and recover databases from backup and losses
- Monitor and tune the database performance

Apart from the Oracle Database software, Oracle also has an array of other products namely:
- Oracle Collaboration Suite
- Oracle Application Server
- Oracle E-Business Suite
- Oracle University
- Oracle Developer Suite
- Oracle Consulting

NOTE: For your individual practice and of essence, you will need an Oracle 10g Database software, a personal computer with 512 megabytes of RAM, 20 Gigabytes of Hard Disk space, a CD ROM drive and a CPU speed of about 533MHz or above. This is just a personal recommendation. Most Pentium 3 computers and above will do, just make sure your RAM is 512MB.

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Building a Solution Colony. Gb!

Gb,

Thanks a bunch!!! This is the beginning of great things here.

All da best to ALL!

Deola

Dipo,

I appreciate your efforts in getting ahead in life. Take care and all the best.

We will always be there for ourselves.

Deola