Skip to main content

Short notes on database schema & database independence- computer science fundamentals tutorial


            Database Schema & Data Independence

PDF version of this post also available. to download the click the link given at the end of this post.  

       Database Schema: - A database schema is the skeleton structure that represents the logical view of the entire database. It defines how the data is organized and how relation among them are associated.  Database schema  formulates all the constrains that are to be applied on the data.
A database schema defines its entities and the relationship among them. It contains descriptive details of the database which can be described by means of schema diagram. A database schema can be divided into two categories.

  I.  Physical database schema: - this schema contain to the actual storage of data and its form of storage like files, indices etc. It defines how the data will be stored in a secondary storage.
 II. Logical database schema: - this schema defines all the logical constrains that need to be applied on the data stored. It defines tables, views and integrality constrains.


    Data Independence: - Data Independence can be explained using    3three schema architecture. Data independence refers characteristic of being able to modified schema at one level of the database without altering the schema at next higher level.
      There are two types of data independence.
    I. Logical data independence: - It refers characteristic being able to change conceptual schema without having to change the external schema. Logical data independence is used to separate the external level from conceptual view. Logical data independence occurs at user inference level.


    II. Physical data independence:- Physical data independence can be defined as capacity to change internal schema without having to change conceptual schema. Physical data independence used to separate conceptual level from internal level. Physical data independence occurs at the logical interference level. 
Data independence
click here for pdf of this post  
PDF of short notes on database schema and data independence
Labels:

Comments

  1. AkanshyaNovember 2, 2020 at 12:11 PM

    Such a very useful article. Very interesting to read this article. I would like to thank you for the efforts you had made for writing this awesome article
    Data Science Training in Hyderabad
    Data Science course in Hyderabad
    Data Science coaching in Hyderabad
    Data Science Training institute in Hyderabad
    Data Science institute in Hyderabad

    ReplyDelete
  2. AnonymousAugust 16, 2022 at 12:43 PM

    I appreciate you taking the time and effort to share your knowledge. This material proved to be really efficient and beneficial to me. Thank you very much for providing this information. Continue to write your blog.

    Data Engineering Services 

    Data Analytics Solutions

    Artificial Intelligence Solutions

    Data Modernization Services

    ReplyDelete

Post a Comment

please subscribe my blog and let me suggest how I improve this site

Popular posts from this blog

type casting in C. - computer science fundamentals tutorial

Typecasting in C Typecasting is also known as "forced conversion". It refers to changing variable one data type to another data type.          Typecasting in can be certified into following two types: - 1) Implicit type casting. 2) Explicit type casting. Implicit type casting : - It is also known as "Automatic type conversion". It is done by compiler on its own without any external trigger from user. Generally takes place when in an expression more than one data type is present in such condition. Type conversion take places to avoid data lose. Example : - #include<stdio.h> main() {   char y = 'a';   int b = y; printf("%c",y); printf("%d",b); } Explicit Type casting : - This process also called 'Type casting' and it is user defined . Here the user can type cast the result to make it of particular data type. Example : - #include<stdio.h> main() { int m...
2 comments
Read more

Important MCQ of RDBMS( Relational database management system)-FCST

Important MCQ of RDBMS  1. A RDBMS consists a collection of ? a. Tables b. Fields c. Records d. Keys  ANS/- a. table 2. The term attribute refers to a ___________ of a table a. Record b. Tuple c. Column d. Key   ans/- c. Column 3. In relational model, the row of table is known to be ?  a. Relation b. Entity field c. Tuple d. Attribute  ans/- C. Tuple 4. . Address field of a person should not be part of primary key, since it is likely to ? a. Dependent b. Too long c. Changed d. Not changed  ans/- c. Changed 5. The relational model is concerned with ? a. Data structure and Data integrity b. Data Manipulation c. Both a and b d. None of these  ans/- c. Both a and b 6. Which is the false statement from the following ? a. A veiw is a named derived table b. A name relation is variable c. A veiw is a named reation and is virtual d. None of these  ans/- d. None of these 7. The union of primary key...
6 comments
Read more

Solve-write C program to find grade of student by using nested else-if statement

C program to find grade of student by using nested else-if statement Problem Description This program take input as your number then show your grade. Problem Solution 1. enter your marks as input. 2. then check your marks with 'If' block's condition. if it satisfied then show your grade as output. 3. if it not satisfied then it checks with all else-if block's condition repeatedly. 4. print the grade according to your given marks as input and exit. Program codes:-   #include<stdio.h> main() { int n; printf("\n enter the marks:"); scanf("%d",&n); if(n>89) printf("O"); else if(n>79) printf("E"); else if(n>69) printf("A"); else if(n>59) printf("B"); else if(n>49) printf("C"); else if(n>39) printf("D"); else printf("F"); } Program explanation:- 1. enter your marks. for example we take 70 . ...
Post a Comment
Read more