A repeating group is a repeating series of information in a database. It is a common problem organizations face, as the same set of information being present in different areas can cause data redundancy and data inconsistency. While the problem can be manageable in small organizations that need to manage only a small set of data, for bigger organizations managing huge volumes of information, it can be a nightmare managing several instances of repeating groups. One of the most common ways of resolving repeating groups is assigning a primary key to the table containing the repeating groups.
The concept of repeating groups can be more easily understood with an example. Suppose that a multinational company has many employees. Roger Davis, Tina Martins and Josh Turner are three employees who all work with both the IT and finance departments and their records such as Employee Code, Employee First Name and Employee Last Name are maintained in the records of both the IT and finance departments. Therefore, since the records are maintained in the databases of multiple departments, it is a case of repeating groups.
This can cause problems when records need to be updated. For example, if Tina Martins gets married and changes her last name to Elton, this means that the records would need to be updated in the databases of both the IT and finance departments. This not only results in a bigger effort, but also is fraught with risks, as mistakes in any record updating could cause major problems.