Introduction to Database

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A database is a collection of information that is arranged to be accessed, managed and updated. The Computer databases typically contain collection of data records or files, containing of information which about sales transactions or interactions with specific customers.

In a relational database, The information is about a specific customer is organized into rows, columns and tables and they are indexed to make it easier to find relevant information through SQL or NoSQL queries. In contrast, a graph database uses nodes and edges to define relationships between data entries and queries require a special semantic search syntax.  As of this writing, SPARQL is the only semantic query language that is approved by the World Wide Web Consortium (W3C). 

Typically, the database manager provides all the users with the ability to control read or write access, specify report generation and analyze usage. Some databases offer ACID (atomicity, consistency, isolation and durability) compliance to guarantee that data is consistent and that transactions are complete.

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Introduction to Database :

  Data may be logical organized into characters, fields, records, files, and database, just as writing can be organized in letters, sentences, words, paragraph, and documents. Example of logical data elements are given below  

Character:

 The most basic data element is the character, which consists of a single alphabetic or numeric or any other symbol. The bit or byte is more elementary data element but those terms refer to the physical storage elements provided by the computer hardware. From a user’s point of view , a character is the most basic element that may be observed and manipulated.  

Field:

The next higher level of data is the data item or field. A field consists of a group of characters. For example, the group of alphabetic characters in a person’s name forms’ a name field. A data field represents an attribute of some entity. For example an employee’s salary is an attribute that is a typical data field used to describe an entity that is an employee.

Record:

Related field of data are grouped to form a record. A record represents a collection of attributes that describes an entity. An example is the payroll for a person, which consists of data fields describing attributes such as the person’s name and social security and  rate of payment. Fixed length records contain in a fixed number of fixed length data fields. Variable-length records contain a variable number of fields and field lengths.

Field:

A group of related records forms a data file or table. Thus an  employee file contains the records of the employees of a firm. Fields are frequently classified by the application for which they are primarily used, such as a payroll file or an inventory file.or the type which they are contain.

Database:  

   

A data base is an integrated collection of logically related records or objects. An object consists of data values describing the attributes of an entity, plus the operations that can be performed upon the data. A database consolidates records previously stored in  separate files into a common pool of data records that provides data for many application. The data stored in a database are independent of the application programs using them and of the type of secondary storage devices on which they are stored.

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