Introduction To Database In Oracle
Introduction to Database
A database is a collection of interrelated data, where some information can be extracted. The collection of data must be logically ordered with some inherent meaning. Example of databases such as we used in our daily life is an attendance register, telephone directory etc. It is managed by a software system and is known as a database management system.
A database management system is a general purpose software system, which enables the user to define and manipulate database. The database management system is the software used to create and maintain the database.
A database management system is a general purpose software system, which enables the user to define and manipulate database. The database management system is the software used to create and maintain the database.
Database Model
• Hierarchical
• Network
• Relational
RDBMS
A Relational database management system (RDBMS) is an information system, which presents an information as row contained in a collection of tables. Each table possesses a set of one or more columns. CODD described the element of a relational database as relation, attributes, domains and the relational operators.
Relational data model was developed by Dr. E.F. CODD in June 1970. E.F. CODD formulated 12 rules for the relational database management system (RDBMS) as CODD Rule.
Oracle
Oracle stands for Oak Ridge Automated Computer and Logical Engine. Oracle is an object relational database management system. As we know, Oracle is the best sophisticated relational database products, which are used by many of the largest Websites.
Oracle is the world’s leading supplier of the information management system. Oracle relational database was the first structured query language supported in the world.
Oracle database
Each time, a database is started, a system global area (SGA) is allocated and Oracle background processes are started.
• SGA (System Global Area)
• Oracle Background Processes
SGA
• Oracle Background Processes
SGA
The system global area is an area of memory used for the database information shared by the database users.
Oracle Background Processes
The background processes and memory buffers refers to Oracle instance. Oracle Instance has two types of processes. These are-
• User processes
• Oracle processes
User Processes
A user processes executes the code of an application program or an Oracle tool such as Oracle Enterprise Manager.
Oracle Processes
Oracle processes are Server processes, which perform work for the user processes and background processes that perform maintenance work for Oracle Server.
