What Is Data Redundancy?


10 Answers

Anonymous Profile
Anonymous answered

Data redundancy is a term used about databases and means simply that some data fields appear more than once in the database. Data redundancy is wasteful and inefficient for several reasons and database designers attempt to eliminate it as far as possible by using a technique called data normalization.

Data can appear multiple times in a database for a variety of reasons, depending on the type of organization of business that the database is designed to serve.  For example, an online business may have the same customer’s name appearing several times if that customer has bought several different products at different times.

This redundancy gives rise to problems for the IT department responsible for maintaining the database because they must update that customer’s details in numerous different locations.  It also means that much storage capacity is wasted, storing the same data multiple times.  Worst of all, if one or more instances of the customer’s name are not updated, then the database will contain inconsistent data, and no one will know which set of data is the correct one.

The solution to this problem was first developed in 1970 by Edgar Codd, the inventor of the relational database.  Put simply, a relational database in one in which important data, such as customers’ names, in stored only once in a single file, but each customer’s field is defined by its relationship to other files - such as individual product sales.

The process of designing a database so that it is not subject to duplication or redundancy of data with its attendant problems of data corruption and inconsistency, is referred to as normalization.

Normalization requires that the database designer stick to rules, established by the database community, to ensure that data is organized efficiently. These rules are called normal form rules. There are a number of normal forms, each more rigorous than the previous, and each containing the rules of the previous form.  Currently there are five levels of normal form.

Anonymous Profile
Anonymous answered
Redundancy is attained when the same data values are stored more than once in a table, or when the same values are stored in more than one table.
One of the biggest disadvantages of data redundancy is that it increases the size of the database unnecessarily
Anonymous Profile
Anonymous answered
It is the unnecessary duplication of data in a database.
Anonymous Profile
Anonymous answered
In a non database systems the same information may be held on several different files, which not only wastes space but makes updating more time consuming. In a database system redundancy is not always completely eliminated, but it is minimised.
chavz pereiz Profile
chavz pereiz answered
Data redundancy is the duplication of data. To get rid of this, data normalization is used in DBMS s.
Anonymous Profile
Anonymous answered
Data redundancy means that repetition when we write any word again again then we can say that is called the data redundancy .
Ellie Hoe Profile
Ellie Hoe answered
Data redundancy is the property of some disk arrays to recover the data stored in the array in the case of disk failure. It is usually related with computer data storage and it provides fault tolerance. There are two two primary ways to achieve data redundancy, firstly, to duplicate the entire set of data and secondly, to store an error correcting code on the array. The only cost of data redundancy is the more utilization of disk space for storing the duplicate data. Data redundancy may also refer to storing same values of data in a data table or more than one table. Sometimes, data redundancy becomes an issue and and to prevent it database normalization is used.
Amit Singh Profile
Amit Singh answered
  Data Redundancy refers to a data organization act that duplicates your unnecessary data within the Microsoft Access database. To make any changes or modification in the redundant data, you are supposed to make changes in the multiple fields of the database. While this is a general behaviour for Spreadsheet and Flat File Database structure, it overwhelms the function of relational database structure.

  The data connections should allow you to keep up and maintain just one data field, only at one location, and make the database the main relational model that would be responsible for any changes, across the data base. The redundant database utilizes lot of place unnecessarily and also creates problem for the maintenance of the database.
  To get details on data redundancy you can log on to www.databasedev.co.uk. You can find more information on search engines like Google and Yahoo. You will get all the possible information from search engines.
Anonymous Profile
Anonymous answered
Its method of preserving data 24x7x365 online irrespective of failure , changeover of hardware or software application !
User who are using this data ( from mappings, from web etc ) don't get interrupted during changeover of failure !

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