A relational database refers to a digital type of database whose organization depicts a relational data model. In a relational database, the model stratifies data into a single or more tables consisting of rows and columns. Each row has a unique key. A database defines entity types, which have their own tables, rows representing its examples and columns representing various values of attribute that describe each instance. As mentioned earlier, each row has a unique key. This is a provision that allows for linking of the key to the other rows in other tables that are related to the given row. This is achieved by storing the unique key of the original row as an attribute of the secondary row. The related tables perceive it as a foreign key. The relational database model was proposed by E.F Cord in 1970.
Formerly, the concept of a database model was hugely pegged on a hierarchical model whose organization of data made use of three elements: Indexes, chains and pointers. Organization of data utilized unique combinations of the three. However, the popularity of the relational database that was fueled by its simplicity saw it cease to be a match to the hierarchical model. It thus became the predominant model soon after its advent and has since reigned undefeated in the world of database modelling. Relational Database Management Systems is a collection of software systems that serve to maintain the relational databases. Relational Database Management systems apply the Structured Query Language in querying and maintaining the databases.
Efficient functionality of a database is enhanced by a set of ACID transactions. ACID implies Atomicity, Consistency, Isolation and Durability. This is set of properties that ensure reliable and effective processing of database transactions. A transaction as a concept of databases refers to a single logical operation on data.
The system generates a new primary key for each new row created. Primary keys in a database defines relationships between tables. The RDBMS is programmable. This is done with the aid of stored procedures, which considerably reduce volumes of information transferred within or outside a system. The prime purpose of this is enhancement of system security. Access is only allowed for the stored procedures and not directly to the tables of data. The basic procedures therefore contain the logics that are needed to alter or update the tables.
A relation is a combination of tuples that possess similar attributes. A tuple defines an object and contains information about the given object. All the data in a table referenced by a given attribute belong to the same domain. Besides, such data follow similar constraints.
The relational model stipulates that tuples of a relation posses no specific order. In addition to this, the tuples do not influence any order on the attributes. Applications gain access to data through various operations such as select, project, insert, join, delete and update.
Database normalization is very cardinal in a relational database. It constitutes procedures that wipe out complex domains and redundant data. Anomalies that are encountered in the manipulation of data and loss of data security is hence checked. Normal forms are the widespread normalization applied to databases.