Transcript of "MS SQL SERVER: Introduction To Database Concepts"
1<br />SQL SERVER: AN INTRODUCTION TO DATABASE CONCEPTS<br />
What is Data?<br />Data is any fact or statistic which can be operated on to <br /> derive meaningful information. It is a raw fact.<br />Simply put:<br />Data is any raw fact<br />Eg: Size = 12 is data<br /> Name = ‘Dennis’ is another data<br /> We cannot derive conclusions directly from the data without processing them<br />Example of a Data<br />
Why is Data important?<br /><ul><li> Data is important because every decision that happens in the world is based on some data
For example, if Jenny wants to buy a laptop, she needs the right data to make appropriate decision on the model. Like its cost, market value, etc.
Hence, every decision depends on the data</li></ul> corresponding to it<br />WHICH SHALL I BUY? <br />Cost = $360<br />Cost = $450<br />
Data in real-world<br /><ul><li> In the real world, data has become ubiquitous, i.e, data is every-where
All aspects of the modern business and domestic life-styles feed of huge amounts of data
The Amount of data is increasing exponentially and we needed a flexible, reliable and secure way to organize this data.
That is where Databases came to our rescue! </li></li></ul><li>What is a Database<br /><ul><li> A Database is a collection of interrelated data
What is so special about a database? </li></ul> Why can’t we just use files? (like text files and word documents). The Next slide answers this Qn.<br />
Problems with files<br />Inconsistency<br /> In a system, a user may use different applications and these may use different formats of data. Hence, interoperability between their data is difficult<br />For Example: Willy, Tim and Rose have been asked to write an essay on MJ, and they use different platforms, they’d have difficulty combining the Data into a single-final document: Incompatibilty<br />X<br />Willy <br />Uses MicrosoftWord<br />Tim <br />Uses WordStar<br />Rose<br />Uses Mellel, a Word processor for Macintosh systems<br />
Problems with files<br />Data Redundancy<br />When handling large amount of data, there might be recurrences of data in case of files. This wastes memory space.<br />Integrity <br />The data is susceptible to corruption due to system failures<br />Concurrent Access anomalies<br />When many people try to write a piece of data concurrently – we’ll have problems in case of files<br />Security problem<br />Ill minded people may get access to our files if they are not secured properly.<br />
Applications of DBMS in real life<br />The DBMS stands for: Database Management System<br />DBMS is a collection of related data (a database) and programs which allow users to work on that data (the management system)<br />DBMS eliminates the various problems that are associated with file storages<br />In real-life, DBMS have a wide spectrum of applications:<br /><ul><li> In Movie theatres for holding ticket reservation details
In Prisons for managing info about the prisoners
In Banks, to manage customer and account info</li></li></ul><li>Database Features<br />A Database consists mainly of Tables<br />A Table is a set of values that is organized using a model of vertical columns (which are identified by their name) and horizontal rows. <br />A Table has a specified number of columns, but can have any number of rows. <br />Each row is identified by the values appearing in a particular column subset which has been identified as a candidate key.<br />Let’s take an example<br />
Database Features<br />Example<br />Consider a database for the dreams that ‘George’ had this week. It has a table called ‘History’ where he stores the date and time at which he dreamt. This table will look as follows:<br />An ‘ATTRIBUTE’ which can uniquely identify a record in a table is called a ‘KEY’. <br />Eg: Dream Number<br />The ‘TYPE’ of data is called as ‘ATTRIBUTE’ or ‘FIELD’. Eg: Date, Time,etc<br />The ‘VALUES’ of a set of attributes, which define a unique object is a ‘RECORD’<br />
Summary<br />Database Concepts<br /><ul><li>Data is a fact
A Table consists of: </li></ul>Records (Rows in a table)<br />Attributes (Columns in a table)<br />Keys (Used to uniquely identify a record in a table)<br />End<br />
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