Hierarchy Of Data

1. Hierarchy of data Data Hierarchy refers to the systematic organization of data, often in a hierarchical form. Data organization involves fields, records, files and so on. •

BIT All data is stored in a computer's memory or storage devices in the form of binary digits or bits. A bit can be either 'ON' of 'OFF' representing 1 or 0.

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BYTE is a group of 8 bits. One byte can represent one character or, in different contexts, other data such as a sound, part of a picture etc.

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FIELD is a group of characters. e.g. data held about a person may be split into many fields including ID Number, Surname, Initials, Title, Street, Town, etc

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RECORD is a group of fields holding all the information about one person or item

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FILE a collection of records. A stock file will contain a record for each item of stock, and so on.

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DATABASE may consist of many different files, linked in such a way that information can be retrieved from several files at once.

4. Database approach to data management Database approaches to data storage support the sharing of data across multiple applications with multiple users. Databases are structured in a way that is meaningful to an organization. For example, if an organization maintains information on suppliers and the geographic areas they service, there would be a link in the database between the suppliers and geographic areas. Databases reduce data redundancy.

A Database Management System (DBMS) is the software that handles all database accesses. A DBMS presents a logical view of the data to the users. How this data is stored and retrieved is hidden from the users. A DBMS ensures that the data is consistent across the database and controls who can access what data. 5. Advantages of database approach One can characterize a DBMS as an "attribute management system" where attributes are small chunks of information that describe something. For example, "color" is an attribute of a car. The value of the attribute may be a color such as "red", "blue" or "silver". Alternatively, and especially in connection with the relational model of database management, the relation between attributes drawn from a specified set of domains can be seen as being primary. For instance, the database might indicate that a car that was originally "red" might fade to "pink" in time, provided it was of some particular "make" with an inferior paint job. Such higher arity relationships provide information on all of the underlying domains at the same time, with none of them being privileged above the others. Throughout recent history specialized databases have existed for scientific, geospatial, imaging, document storage and like uses. Functionality drawn from such applications has lately begun appearing in mainstream DBMSs as well. However, the main focus there, at least when aimed at the commercial data processing market, is still on descriptive attributes on repetitive record structures.Thus, the DBMSs of today roll together frequently-needed services or features of attribute management. By externalizing such functionality to the DBMS, applications effectively share code with each other and are relieved of much internal complexity.