1) Define Database.
A prearranged collection of figures known as data is called database.
2) What is DBMS?
Database Management Systems (DBMS) are applications designed especially which enable user interaction with other applications.
3) What are the various kinds of interactions catered by DBMS?
The various kind of interactions catered by DBMS are:
• Data definition
• Update
• Retrieval
• Administration
4) Segregate database technology's development.
The development of database technology is divided into:
• Structure or data model
• Navigational model
• SQL/ relational model
5) Who proposed the relational model?
Edgar F. Codd proposed the relational model in 1970.

6) What are the features of Database language?
A database language may also incorporate features like:
DBMS-specific Configuration and management of storage engine
Computations to modification of query results by computations, like summing, counting, averaging, grouping, sorting and cross-referencing Constraint enforcement Application Programming Interface
7) What do database languages do?
As special-purpose languages, they have:
• Data definition language
• Data manipulation language
• Query language
8) Define database model.
A data model determining fundamentally how data can be stored, manipulated and organised and the structure of the database logically is called database model.
9) What is SQL?
Structured Query Language (SQL) being ANSI standard language updates database and commands for accessing.
10) Enlist the various relationships of database.
The various relationships of database are:
• One-to-one: Single table having drawn relationship with another table having similar kind of columns.
• One-to-many: Two tables having primary and foreign key relation.
• Many-to-many: Junction table having many tables related to many tables.

11) Define Normalization.
Organized data void of inconsistent dependency and redundancy within a database is called normalization.
12) Enlist the advantages of normalizing database.
Advantages of normalizing database are:
• No duplicate entries
• Saves storage space
• Boasts the query performances.
13) Define Denormalization.
Boosting up database performance, adding of redundant data which in turn helps rid of complex data is called denormalization.
14) Define DDL and DML.
Managing properties and attributes of database is called Data Definition Language(DDL).
Manipulating data in a database such as inserting, updating, deleting is defined as Data Manipulation Language. (DML)
15) Enlist some commands of DDL.
They are:
Create is used in the CREATE TABLE statement. Syntax is:
CREATE TABLE [column name] ( [column definitions] ) [ table parameters]
It helps in modification of an existing object of database. Its syntax is:
ALTER objecttype objectname parameters.
It destroys an existing database,, table or view. Its syntax is:
DROP objecttype objectname.

16) Define Union All operator and Union.
Full recordings of two tables is Union All operator.A distinct recording of two tables is Union.
17) Define cursor.
A database object which helps in manipulating data row by row representing a result set is called cursor.
18) Enlist the cursor types.
They are:
• Dynamic: it reflects changes while scrolling.
• Static: doesn't reflect changes while scrolling and works on recording of snapshot.
• Keyset: data modification without reflection of new data is seen.
19) Enlist the types of cursor.
They types of cursor are:
• Implicit cursor: Declared automatically as soon as the execution of SQL takes place without the awareness of the user.
• Explicit cursor: Defined by PL/ SQL which handles query in more than one row.
20) Define sub-query.
A query contained by a query is called Sub-query.

21) Why is group-clause used?
Group-clause uses aggregate values to be derived by collecting similar data.
22) Compare Non-clustered and clustered
Both having B-tree structure, non-clustered has data pointers enabling one table many non-clustered https://robozzlab.comes while clustered is distinct for every table.
23) Define Aggregate functions.
Functions which operate against a collection of values and returning single value is called aggregate functions
24) Define Scalar functions.
Scalar function is depended on the argument given and returns sole value.
25) What restrictions can you apply when you are creating views?
Restrictions that are applied are:
• Only the current database can have views.
• You are not liable to change any computed value in any particular view.
• Integrity constants decide the functionality of INSERT and DELETE.
• Full-text definitions cannot be applied.
• Temporary views cannot be created.
• Temporary tables cannot contain views.
• No association with DEFAULT definitions.
• Triggers such as INSTEAD OF is associated with views.

26) Define "correlated subqueries".
A 'correlated subquery' is a sort of sub query but correlated subquery is reliant on another query for a value that is returned. In case of execution, the sub query is executed first and then the correlated query.
27) Define Data Warehousing.
Storage and access of data from the central location in order to take some strategic decision is called Data Warehousing. Enterprise management is used for managing the information whose framework is known as Data Warehousing.
28) Define Join and enlist its types.
Joins help in explaining the relation between different tables. They also enable you to select data with relation to data in another table.
The various types are:
• INNER JOINs: Blank rows are left in the middle while more than equal to two tables are joined.
• OUTER JOINs: Divided into Left Outer Join and Right Outer Join. Blank rows are left at the specified side by joining tables in other side.
29) What do you mean by hunting?
https://robozzlab.comes help in improving the speed as well as the query performance of database. The procedure of boosting the collection of https://robozzlab.comes is named as hunting.
30) How does hunting help in improving query performance? hunting helps in improving the speed as well as the query performance of database. The followed measures are achieved to do that:
• The query optimizer is used to coordinate the study of queries with the workload and the best use of queries suggested based on this.
•, query distribution along with their performance is observed to check the effect.
• Tuning databases to a small collection of problem queries is also recommended.

31) Enlist the disadvantages of query.
The disadvantages of query are:
• No https://robozzlab.comes
• Stored procedures are excessively compiled.
• Triggers and procedures are without SET NOCOUNT ON.
• Complicated joins making up inadequately written query.
• Cursors and temporary tables showcase a bad presentation.
32) Enlist ways to efficiently code transactions.
Ways to efficiently code transactions:
• User input should not be allowed while transactions.
• While browsing, transactions must not be opened of data.
• Transactions must be kept as small as possible.
• Lower transaction segregation levels.
• Least information of data must be accessed while transacting.
33) What is Executive Plan?
Executive plan can be defined as:
• SQL Server caches collected procedure or the plan of query execution and used thereafter by subsequent calls.
• An important feature in relation to performance enhancement.
• Data execution plan can be viewed textually or graphically.
34) Define B-trees.
A data structure in the form of tree which stores sorted data and searches, insertions, sequential access and deletions are allowed in logarithmic time.
35) Differentiate Table Scan from Scan.
Iterating over all the table rows is called Table Scan while iterating over all the items is defined as Scan.

36) What do you mean by Fill Factor concept with respect to https://robozzlab.comes?
Fill Factor can be defined as being that value which defines the percentage of left space on every leaf-level page that is to be packed with data. 100 is the default value of Fill Factor.
37) Define Fragmentation.
Fragmentation can be defined as a database feature of server that promotes control on data which is stored at table level by the user.
38) Differentiate Nested Loop, Hash Join and Merge Join.
Nested loop (loop over loop)
An outer loop within an inner loop is formed consisting of fewer entries and then for individual entry, inner loop is individually processed.
• Select col1.*, col2.* from coll, col2 where coll.col1=col2.col2;
It's processing takes place in this way:
For i in (select * from col1) loop
For j in (select * from col2 where col2=i.col1) loop
Results are displayed;
End of the loop;
End of the loop;
The Steps of nested loop are:
• Identify outer (driving) table
• Assign inner (driven) table to outer table.
• For every row of outer table, access the rows of inner table.
Nested Loops is executed from the inner to the outer as:
• outer_loop
• inner_loop
• Hash join
While joining large tables, the use of Hash Join is preferred.
Algorithm of Hash Join is divided into:
• Build: It is a hash table having in-memory which is present on the smaller table.
• Probe: this hash value of the hash table is applicable for each second row element.
• Sort merge join
Two independent sources of data are joined in sort merge join. They performance is better as compared to nested loop when the data volume is big enough but it is not good as hash joins generally.The full operation can be divided into parts of two:
Sort join operation :
Get first row R1 from input1
Get first row R2 from input2.
Merge join operation:
'while' is not present at either loop's end.
if R1 joins with R2
next row is got R2 from the input 2
return (R1, R2)
else if R1 < style> next row is got from R1 from input 1
next row is got from R2 from input 2
end of the loop
39) What is Database partitioning?
Division of logical database into independent complete units for improving its management, availability and performance is called Database partitioning.
40) Explain the importance of partitioning.
Splitting of one table which is large into smaller database entities logically is called database partitioning. Its benefits are:
• To improve query performance in situations dramatically when mostly rows which are heavily accessed are in one partition.
• Accessing large parts of a single partition
• Slower and cheaper storage media can be used for data which is seldom used.

41) Define Database system.
DBMS along with database is called Database system.
42) What do you mean by Query Evaluation Engine?
Query Evaluation Engine executes the low-level instructions that are generated by the compiler.
43) Define DDL Interpreter.
DDL statements are interpreted and recorded in tables called metadata.
44) Define Atomicity and Aggregation.
Atomicity: It's an all or none concept which enables the user to be assured of incomplete transactions to be taken care of. The actions involving incomplete transactions are left undone in DBMS.
Aggregation: The collected entities and their relationship are aggregated in this model. It is mainly used in expressing relationships within relationships.
45) Enlist the various transaction phases.
The various transaction phases are:
• Analysis Phase.
• Redo Phase
• Undo Phase

46) Define Object-oriented model.
Compilations of objects make up this model in which values are stored within instance variables which is inside the object. The object itself comprises bodies of object for its operation which are called methods. Objects containing same kind of variables and methods are called classes.
47) Define Entity.
It can be defined as being a 'thing' with an independent existence in the real world.
48) What do you mean by Entity type?
A set of entries having similar attributes are entity types.
49) Define Entity Set.
Compilation of all entries of any particular type of entry in the database is called Entity Set.
50) What do you mean by Entity type extension?
Compilation of similar entity types into one particular type which is grouped together as an entity set.

HTML5 Interview Questions

Q-1. What Are The New DocType And Charset In HTML5?
The DocType element communicates the HTML version to the browser. It usually appears in the first line of code of an HTML page. Unlike the earlier versions/standards of HTML, DocType has got a simplified format in HTML5.
<!doctype html>
The CharSet is a new meta tag attribute in HTML5 which configures the character encoding.
<meta charset=”UTF-8″>
Q-2. What All New Form Elements Got Introduced In HTML5?
Here is the list of new form elements available in HTML5.
<datalist> – It specifies a list of options for input controls.
<keygen> – This tag generates an encryption key.
<output> – It defines the result of an expression.
Q-3. Which Of The HTML5 Elements Support Media Content?
Following HTML5 elements supports media content.
<audio> – It specifies sound content.
<video> – It links to a video.
<source> – This tag specified the source of video and audio links.
<embed> – It acts as a container for external applications.
<track> – This element defines tracks for video and audio.
Q-4. What Are Various Elements That Provide Better Structuring In HTML5?
Following HTML5 elements focus on improving the structuring.
<article> – This element allows to specify an article.
<aside> – It allows to view content other than the page content.
<bdi> – It lets a part of text getting formatted in a different direction from other text.
<command> – It displays a button element which processes a command upon user action.
<details> – It adds additional details that a user can show or hide.
<dialog> – It initializes a dialog box or popup window.
<figure> – This element can show illustrations, diagrams, photos, and code listings.
<figcaption> – It adds a caption for the image specified by a

<footer> – This tag appends a footer to a document.
<header> – This tag inserts a header into a document.
<hgroup> – If a page includes multiple headings, then this tag groups them into a set of <h1> to <h6> elements.
Q-5. What Is SVG And Why Do You Use It?
SVG is an acronym for Scalable Vector Graphics as recommended by W3C.
Its purpose is to display the vector-based graphics over the Web.
The graphics use an XML format.
SVG graphics are of higher quality and does not lose it even when resized.
All elements and attributes of SVG support animation.

Q-6. What Does Canvas Mean In HTML? And What Is Its Default Border Size?
Canvas is an HTML5 element which can draw graphics on the fly with the help of JavaScript. The <canvas> element can only contain graphics. It supports a no. of methods for drawing paths, boxes, circles, text, and images.
By default, It has no border. However, it allows using CSS to change the border style.
Q-7. How Does Canvas Differ From SVG?
Here are a few points elaborating the differences between Canvas and SVG.
Canvas depends on the resolution whereas SVG doesn’t.
It does not allow event handlers whereas SVG does provide the support for event handlers.
Canvas is ideal for graphic-intensive games whereas SVG doesn’t intend for gaming.
It works well for small rendering areas whereas SVG may perform better for large rendering areas like Google map.
Q-8. Does HTML5 Provide Drag And Drop Facility? How Do You Set An Image As Draggable?
To set an image as draggable, initialize the draggable attribute with true.
<img draggable="true">
Q-9. What Is HTML5 Web Storage?
HTML5 brought this new ability to store web pages within the browser cache. This web storage is not only faster than the cookies but secured too. It is capable of storing a large amount of data without compromising the performance of the website.
Also, note that the cached data is not must for every server request. Instead, it gets utilized only when the page asks for it. And the web page which receives the data stored can access it.
Q-10. What Is The Difference Between LocalStorage And SessionStorage Objects?
Following points describes the differences between the localStorage and sessionStorage objects.
The <localStorage> object doesn’t have an expiry for the stored data whereas the <sessionStorage> object keeps it only for a single session.
The <localStorage> object doesn’t have a provision to delete the data upon closing of browser window whereas the <sessionStorage> object clears it simultaneously with the window closing down.

CSS3 Interview Questions

Q-1. How Does CSS3 Differ From CSS?
CSS3 is the most recent version of CSS. It has introduced a bunch of new tags to give a better user experience. Some of the features are rounded corners, animation, custom layout, and media queries.
Q-2. How Does CSS3 Support Responsive Web Designing?
CSS3 has come up with a media query feature. It supports RWD (Responsive Web Design) and does help in making a website responsive.
Q-3. What Is A CSS Selector?
A CSS selector is an expression following the CSS rules and used to select the element we want to style. And CSS selector syntax means how we write or use those selectors in the CSS editor. Please note that a CSS selector can help you find or select HTML elements based on their name, id, class, attribute, and more.
Q-4. What Are The Different Types Of CSS?
Below are the different types of CSS.
Embedded – It adds the CSS styles using the <style> attribute.
Inline – It adds the CSS to the HTML elements.
Linked/External – It adds an external CSS file to the HTML document.
Q-5. What Is An ID Selector?
The ID selector uses the “ID” attribute of the target HTML element to select it. The constraint to work is that the ID should be unique within a page so that the selector can point it out correctly. To build an ID selector expression, start with a hash (#) character, followed by the id of the element. Here is an example which selects a paragraph element using its ID.
#sample {padding: 10px;}
<p id="selector">...</p>

Q-6. What Does The Class Selector Mean?
In CSS, a class selector is an expression which begins with a full stop (“.”) and followed by the name of a class. The class attribute could be a space-separated list of items, and one of those must match with the class name specified in the selector.
Here is an example which selects a div and modified its style.
.sampleclass {font-family: Ariel; font-size: 10; background: green;}
<div class="sampleclass">....</div>
Q-7. What Is The Difference Between An ID Selector And The Class Selector?
An ID Selector finds and modifies the style to only a single element whereas a class selector may apply to any no. of HTML elements.
Q-8. What Is Grouping In CSS3?
Grouping makes it possible to apply the same style to multiple HTML elements (Classes/Tag/ID) within a single declaration. It happens by specifying all the selectors separated by commas.
#page p, ul { padding-top: 10px; margin: 0; }
Q-9. What Are Child Selectors In CSS?
A child selector looks up for the child of some element. To form a child selector, we need two or more selectors separated by “greater than” symbol.
Let’s take an example. We have a <ul> tag inside a paragraph. Here, <ul> is the child of the paragraph element. So, to apply the CSS styles, we can use the following syntax.
p > ul { font-size:15px; }
Q-10. How Do You Make Border Rounded With CSS3?
Yes, in CSS3, there is a <border-radius> property which allows creating an element with rounded corners. We can apply the same style to all the sides and make the corners round. The <border-radius> property has four individual properties <border-top-left-radius>, <border-top-right-radius>, <border-bottom-left-radius> and <border-bottom-right-radius>.

Q-11. What Is Webkit In CSS3? And Why Is It Used?
Webkit is a core software component which is responsible for rendering HTML and CSS in browsers like Safari and Chrome. There are other similar rendering engines like Gecko for Mozilla, Presto for Opera, and Edge for IE.
To enable Webkit on a web page, it requires prefixing the <-webkit> keyword with CSS values.
Here is an example of CSS using the Webkit feature.
.box_shadow {
-webkit-box-shadow: 0px 0px 5px 0px #ffffff;
box-shadow: 0px 0px 5px 0px #ffffff;
Q-12. How Do You Enable Pagination Using CSS3?
Making use of a <ul-li> structure, we can allow Pagination with CSS3.
<div class="main_container">
<div class="pagination">
<li><a href="#"></a></li>
<li><a href="#"></a></li>
<li class="active"><a href="#"></a></li>
<li><a href="#"></a></li>
Q-13. What Are Transitions In CSS3?
CSS3 transitions help to create a super easy and fast animation effect. They not only give us control to change the value of a property but also let it proceed slowly for the given duration.
We can use the following CSS properties.
transition, transition-delay, transition-duration, transition-property, and transition-timing-function.
Q-14. What Is CSS Box Model And What Are Its Components?
The CSS Box Model represents a box that confines every HTML element such as a text box, a menu or a button. It has primarily four core components.
Margin – It refers to the topmost layer of the box.
Border – The padding and content options work around the Border. Changing the background color can also affect the Border.
Padding – It defines spacing around the box.
Content – It represents the actual content to be shown.
Q-15. What Are Media Queries In CSS3 And Why Do You Use Them?
Media queries are one of the latest features of CSS3 used to define responsive styles for devices of different shapes and sizes.
They are the powerful CSS tool which makes it easy to create responsive design for tablets, desktop, mobiles devices. They can help to adjust the Height, Width, Viewport, Orientation, and Resolution.
@media screen and (min-width: 480px) {
body {
background-color: #ffffff;

Q-16. What Are Pseudo-Classes In CSS?
A Pseudo-Class is a CSS technique to set the style when the element changes its state.
For example
Edit the style upon mouse hover event.
Set the style when an element gets focus.
Apply different styles for visited/unvisited links.
selector:pseudo-class {
Q-17. What Is The Use Of Float Property In CSS?
With the help of float property, we can control the position and layout of elements on a web page.
For example, it can define the placement of a <div> either to the right or left side.
Also, to note that it doesn’t interfere with the elements appearing before.
div {
float: left;
Q-18. Which Property Do You Use To Modify The Face Of A Font In CSS?
First of all, please note that both the terms <@font-face> and <font-family> refers to changing the font of an HTML element. However, there is a slight difference between the two.
1. The is a CSS rule that facilitates the use of custom fonts on a web page.
2. The is a CSS property which specifies the font for a web element.
Also, to change the font or face of a font, we need to set the <font-family> property. Please see the below example.
@font-face {
font-family: myCustomFont;
src: url(sansation_light.woff);
body {
font-family: 'myCustomFont', Fallback, Ariel;
Q-19. How Do You Add Comments In CSS?
It is just the same in CSS as we do in JavaScript. Place the comments inside the enclosing /* and */.
Q-20. What Is Z- And How Does It Work?
The z- is a CSS property which defines the stack order of web elements. Higher order elements will appear before any lower order element.
Note – The z- only applies to the positioned elements. For example, position:absolute, position:relative, or position:fixed.
div {
position: absolute;
left: 10px;
top: 10px;
z- -1;

JavaScript Interview Questions

Q-1. What Are The Core Data Types Available In JavaScript?
Below is the list of data types available in JavaScript.
Q-2. What Is Difference Between <Window.Onload> And <OnDocumentReady>?
The <onload> event doesn’t invoke until the page gets finished loading of CSS and images. It could cause a significant delay in rendering of the web page.
As a web developer, we have to ensure the page should load as quick as possible. The event <onDocumentReady> lets us only wait for the DOM to initialize instead of delaying any action required.
Q-3. What Is The Difference Between Undefined Value And Null Value?
<undefined> Vs. <null> value
1. A variable will have <undefined> value if it has a declaration but not assigned any value.
2. A variable will yield a <null> value if assigned with null.
3. <undefined> is a type itself whereas <null> is an object.
4. <undefined> value is set via JavaScript engine whereas null value is set directly in the code.
Q-4. How Do You Change The Style/Class On Any Element From JavaScript?
Following JavaScript will modify the style/class of an HTML element.
document.getElementById(“input”).style.fontSize = “10”;
-or- document.getElementById(“button”).className = “classname”;
Q-5. What Is Namespacing In Javascript And Where Is It Used?
Using global variables is a bad practice in most programming languages including JavaScript. But sometimes, it is not possible to avoid global variables. So JavaScript introduces the concept of namespacing which ties down a part of the code and register it with a unique name.
A namespace is just an object in JavaScript that acts as a container for methods, properties, and other types. It encourages modularity and reusability in a web application.

Q-6. How Does JavaScript Handle Automatic Type Conversion?
As per ECMA Script standard, JavaScript is dynamic as well as weakly typed language with first-class functions which means – “A JavaScript function can accept other functions as arguments.”
Also, it does support auto-type conversion. Whenever an operator or a statement doesn’t get a value of the expected type, then the conversion takes place automatically.
Q-7. What Are Different Types Of Popup Boxes Available In JavaScript?
JavaScript allows the following types of dialog boxes.
Alert – It just has a <Ok> button to proceed.
Confirm – It pops up a window showing up <Ok> and <Cancel> buttons.
Prompt – It gives a dialog asking for user input followed by showing / buttons.
Q-8. What Is The Difference Between <Alert()> And <Confirm()> Popup Boxes?
The <alert()> method displays a message in a popup box and has only one <Ok> button.
But the <confirm()> method asks for confirmation from the user so that it can get the opinion of visitors. It has two buttons, i.e., <Yes> and <No>.
In short, <alert()> popup is to display the messages to the users whereas the <confirm()> dialog is useful for knowing the choices of the visitors.
Q-9. What Is Scope In JavaScript?
The general meaning of scope is the accessibility of functions and variables in an application. Usually, we use them in two ways, i.e., Local and Global.
A) Local Scope
If we declare a function or variable inside a function, then we can access it only inside that function. // code here can not use myLocalVar
function myFunction() {
var myLocalVar = "I'm Local";
// code here can use myLocalVar
B) Global Scope Declaring a variable anyw
here on the page would mean that we can access it from any of the functions on that page.
var myGlobalVar = "I'm Global";
// code here can use myGlobalVar
function myFunction() {
// code here can use myGlobalVar
Q-10. What Types Of Comments Does JavaScript Support?
There are two ways to insert comments in JavaScript code.
For single line comment, we can use // (double forward slash).
For multiline comment, we enclose comments using /* */.

Q-11. How Do You Distinguish Between An Undefined And Undeclared Variable?
Undefined refers to a variable which has declaration but not initialized yet. However, an undeclared
variable is one which has a reference in the code without being declared.
var iExistButUndefined;
alert(iExistButUndefined); // undefined
alert(iMNotDeclared); // accessing an undeclared variable
Q-12. What Are == And === Operators In JavaScript And How Do They Differ?
== – Equal to operator
=== – Equal value and equal type operator
Both of the above operators belong to the Comparison Operator Category. However, the equality operator <==> only checks for the value whereas the strict equality operator <===> checks for the values as well as types.
Q-13. What Relates JavaScript With ECMA Script?
ECMA Script is another technical name for JavaScript as it is also known as LiveScript. The current JavaScript that you may see running in browsers is ECMA Script revision 6.
Q-14. What Is The Mechanism To Submit A Form Using Javascript?
We can call the following method to submit a form using JavaScript.
0 -> of the form
Note – if we have more than one form, then the first one stays at 0, next is at 1 and so on.
Q-15. What Is The Mechanism To Detect The Operating System On The Client Machine?
The following JavaScript property gives back the operating system version on the client machine. It returns the OS version string.

Q-16. What Is The Function Of Delete Operator In JavaScript?
The delete operator clears all the variables and objects used on the web page. But it leaves the variables declared using the var keyword as is.
Q-17. What Is The Use Of <This> Keyword In JavaScript?
The <this> keyword refers to the current object in the program. It is usually available inside a method for referencing the current variable or current object.
Q-18. What Does The <TypeOf> Operator Do In JavaScript?
The <typeof> operator give back the type of a variable in the form of a string.
Q-19. How Do You Make Generic Objects In JavaScript?
JavaScript provides a new operator to produce generic objects.
Follow the below example creating a generic object.
var obj = new object();
Q-20. What Does The “Defer” Attribute Do In JavaScript?
The <defer> attribute is primarily of boolean type. It delays executing a javascript until the page completes the parsing process.
Below is the example of JavaScript code deferring a sample script.
<script src="/mysample.js" defer></script>