ystems started the current domination in database solutions around 1985. The most popular relational database management systems include Oracle, Ingres, and Informix. The key characteristics of a relational database are: Objects have a complex relationship to each other, which is the key to the way a relational database works. Queries can be based on complex relationships between objects. Relational databases support sophisticated transaction-based updates, and provide update tools that make use of these. The database is essentially centralized. In some cases, there is limited replication to give copies of the entire database. The schema is entirely application/user defined. A relational database is a general-purpose tool, which can be used to deal with a very wide range of problems. Generally, multiple databases do not share common schema.The first characteristic is the key benefit of a relational system. Whenever there is a need to perform sophisticated analysis on data and the relationship between elements of data is non-trivial; a relational database is a good choice. The key strength of a relational database is the ability to make complex queries about the relations between objects. Examples of relational systems include an accounting system or an enterprise resource planning system. Oracle makes it very easy to link the data in multiple tables. It stores data in two or more tables and enables you to define relationships between the tables. The link is based on one or more fields common to both tables. Common features among relational databases include: Persistent storage of arbitrary size Transaction management for concurrency Transaction management for recovery Authorization and security Consistency and integrity Query language Logical and physical data independence Application generation Client-server dis...
