Object Relational Database Management System And Oracle example essay topic

Databases have been around for a while and each year new developments and types are born. All databases are not created equal and in order to develop database driven applications successfully and on time, you need to understand exactly what your particular database can do and how it does it. In this new era of computer applications and modern technological advances, databases have play an important role in finances, companies, enterprises, small business and other just to name a few. Database management is the core arrangement of data for an organization to keep the data organized, clean and easy to manage. Since technology has evolved so much from old times to this new era, new database companies have also emerge. Few of these companies are: Microsoft SQ Server, MySQL, Oracle, PeopleSoft, Microsoft Access, Microsoft FoxPro, DB 2 and many others that engage the database business.

Oracle is designed to be a very portable database. It could be implemented in Microsoft Windows, UNIX, and the OS/390 Mainframe. On UNIX, Oracle is implemented as a single, threaded process, which is the appropriate implementation mechanism on this platform. There's a clean and vital connection between the oracle DBA's functions and those of the UNIX (or windows) administrator in your organization.

Your database and the database software will be running on a physical UNIX (or Windows / Linux) server and will be run on a UNIX (or windows / Linux) operating system. Depending on the size of your organization and the role within it, you may need anywhere from a basic to a thorough understanding of UNIX system administration. There are many challenges developing a multi-user database, one of the key challenges in developing multi-user, database-driven applications is to maximize concurrent access, but at the same time, to ensure that each user is able to read and modify the data in a consistent fashion. All work in a relational database is essentially performed through the use of a database language called Structure Queue Language (SQL). SQL is an English-like language that enables you to manipulate data in a database.

SQL statements can be divided into two major categories: data definition language (DDL) and data manipulation language (DML). DDL statements are used to built and alter database structures such as tables. Database schemas are defined and constructed using DDL statements. DML statements are used to manipulate data in the database table.

With DML statements you can delete, update, and insert tuples that are part of a relation. Transactions are one of the features that set a database apart from a file system. In a file system, if you are in the middle of writing a file and the operating system crashes, this file is likely to be corrupted. It is true there are file systems, and the like, which may be able to recover your file to some point in time. This is the main purpose of transactions in the database; they take the database from one consistent state to the next. That is their job.

Relationships shows how many instances of one entity can be relate on an instance of another entity. There are three types of database relationships. -One-to-one relationship: For example, an employee works in only on department. A department employs one and only one employee.

It is very unusual to find a true one to one relationship in the real world, and they are normally used to split tables for security reasons. -One-to-many relationships: For example, an entity called customer can check out many books from a library. One and only one customer can borrow each book. So, the entity customer and the entity book have a one to many relationships. Off course, the relationship may not exist if you have a customer who has not yet borrowed a book.

So the relationship is actually "one customer may borrow none, one, or many books". -Many-to-many relationships: As an example, let's take an entity called Movie Start and an entity called Movie. Each Movie Start can start in several Movies, and each Movie may have several Movies Starts. In real life, a many to many relationship is broken down usually into a simpler one to many relationship, which happens to be the pre-dominant form of "cardinality" in the relationships between entities.

A primary key is a filed or a combination of fields (columns, to be accurate) that uniquely identify each record or row. A primary key is the candidate key that's chosen to serve as the unique identifier (UID) for that entity (or table). Keys are vital when you come to the point of physical building of the entity models, and are from among the attributes of the entity that you chose a primary key. It is common to use social security number because it is obvious that every person has a unique social security number.

If there is not appropriate field you can chose as a primary key, you can use system-generate numbers to uniquely identify your rows. A primary key most be unique and present in every row of the table to maintain the validity of the data. Object Database Management Systems (ODBMS) are still not at the point were they can seriously compete with traditional relational databases for several reasons. The relational model and the object model refer to two different streams in data modeling, and a newer extension of the relational model has come forth to bridge the gap between the two. This new model is the object-relational database management system (ORDBMS), and Oracle has adopted this ODBMS model since Oracle 8 version of its server software. Oracle defines the 9 i version (as well as the 8 i version) of its database server as an ORDBMS.

The relational model has several limitations. One of the biggest problems with the relational model is its limited capability to represent real-world entities, which are much more complex than what can be represented in tuples and in relations. The object model is base primarily on object-oriented programming languages such as C++, Java, and Smalltalk. ODBMS are created by combining database capabilities to object oriented programming languages.

The object relational model (ORDBMS) attempts to combine the best that relational model have to offer while adding as much of the objects-oriented methodology as possible. Oracle with Experts..