he relational database model was first introduced by E.F. Codd of IBM in 1969. In the relational model, data are structured into tables (i.e., "relations") consisting of rows and columns. Each row contains a single record comprised of individual data elements (or "attributes") organized in columns containing elements of the same kind according to the rules defined for that column. Alternate database models include the network, hierarchical, flat file, and object-oriented models. 1.Simplicity
oThe relational model structures data in a manner that avoids complexity. The table structure is an intuitive organization familiar to most users, particularly those who have worked with physical or software spreadsheets, check registers or other tabular data. Data are organized naturally within the model, simplifying the development and use of the database. Ease of Data Retrieval
oUnder the relational model, accessing data in a database does not require navigating a rigid pathway through a tree or hierarchy. Users can query any table in the database, and combine related tables using special join functions to include relevant data contained in other tables in the results. Results can be filtered based on the content of any column, and on any number of columns, allowing users to easily retrieve meaningful results. Users can choose which columns to include in the results so that only relevant data are displayed. Data Integrity
oData integrity is an essential feature of the relational model. Strong data typing and validity checks ensure data fall within acceptable ranges, and required data are present. Referential integrity among tables prevents records from becoming incomplete or orphaned. Data integrity helps to ensure accuracy and consistency of the data. Flexibility
oThe relational database model is naturally scalable and extensible, providing a flexible structure to meet changing...