MongoDB

mongodb

MongoDB is an open-source document database and leading NoSQL database.

It is written in C++.

It is a cross-platform.

Document oriented data based.

that provides, high performance, high availability, and easy scalability.It works on concept of collection

and document.

Basic syntax of use DATABASE statement is as follows −

.use DATABASE_NAME 

use music

Your created database (mydb) is not present in list.

To display database, you need to insert at least one document into it.

db.movie.insert({"name":" songdetails"})


MongoDB db.dropDatabase() command is used to drop a existing database.

db.dropDatabase()

To check the list of available databases by using the command, show dbs.

>show dbs
local      0.78125GB
mydb       0.23012GB
test       0.23012GB

MongoDB db.createCollection(name, options) is used to create collection.

db.createCollection(name, options)

MongoDB's db.collection.drop() is used to drop a collection from the database.

db.COLLECTION_NAME.update(SELECTION_CRITERIA, UPDATED_DATA)

Example:

1) Create a Database called music​.

• use music

2) Create a collection called songdetails​.

• db.createCollection("songdetails")

3) Create the above 5 song documents.

db.songdetails.insert({"Song Name":"Thaniye Thananthaniye","Film":"Rhythm","Music Director":"A.R.Rahman","Singer":"Shankar mahadevan"})

WriteResult({ "nInserted" : 1 })

db.songdetails.insert({"Song Name":"Evano Oruvan","Film":"Alai Payuthey","Music Director":"A.R.Rahman","Singer":"Swarnalatha"})

WriteResult({ "nInserted" : 1 })

db.songdetails.insert({"Song Name":"Roja Poonthottam","Film":"Kannukkul Nilavu","Music Director":"Ilaiyaraja","Singer":"Unnikirishnan,Anuradha Sriram"})

WriteResult({ "nInserted" : 1 })

db.songdetails.insert({"Song Name":"Vennilave Vennilave vinnaithandi","Film":"Minsara Kanavu","Music Director":"A.R.Rahman","Singer":"Hariharan,Sadhana Sargam"})

WriteResult({ "nInserted" : 1 })

db.songdetails.insert({"Song Name":"Sollamal Thottu Chellum Thendral","Film":"Dheena","Music Director":"Yuvan Shankar Raja","Singer":"Hariharan"})

4) List all documents created.

• db.songdetails.find().pretty()

5) List A.R.Rahman’s songs.

• db.songdetails.find({"Music Director":"A.R.Rahman"})

6) List A.R.Rahman’s songs sung by Unnikrishnan.

• db.songdetails.find({"Music Director":"Ilaiyaraja","Singer":"Unnikirishnan,Anuradha Sriram"},{"Song Name":1,_id:0})

7) Delete the song which you don’t like.

• db.songdetails.remove({"Song Name":"Evano Oruvan"})

8) Add new song which is your favourite.

• db.songdetails.insert({"Song Name":"Kannana Kanne","Film":"Viswasam","Music Director":"D.imman","Singer":"Sid Sriram"})

9) List Songs sung by Sid sriram from Viswasam film.

• db.songdetails.find({"Film":"Viswasam","Singer":"Sid Sriram"},{"Song Name":1,_id:0})

10)List out the singers’ names in your document.

• db.songdetails.find({},{"Singer":1,_id:0}).pretty()

example2

1) Create a Database called student

use student

2) Create a collection called ​studentmarks

db.creatCollection(“studentmarks”)

3) Create the documents listed in above table.

db.songdetails.insert({"name":"Malal","maths_marks":45,"english_marks":53,"science_marks":72})

.

.

.

4) Increase the maths marks of Mala by 6 marks

5) List the names of students who got more than 50 marks in Maths Subject.

6)Add a new column(field) for Average for all students.

db.studentmarks.aggregate({$addFields:{“avarage”:””}}).pretty()              

7) Update Marks_Science=75 to Lucky .

db.studentmarks.update({“name”:”Lucky”},{$set:{science_marks”:75}})

8) List the names who got more than 50 marks in all subjects.

db.studentmarks.find({$and:[{"english_marks":{$gt:50}},{"science_marks":{$gt:50}},{"maths_marks":{$gt:50}}]},{"name":1,_id:0})

9) List the names who got less than 50 marks in Maths subject and more than 50 marks in English

db.studentmarks.find({$and:[{"english_marks":{$gt:50}},{"maths_marks":{$lt:50}}]},{"name":1,_id:0})

10) List the names who got less than 40 in both Maths and Science.

db.studentmarks.find({$and:[{"science_marks":{$lt:40}},{"maths_marks":{$lt:40}}]},{"name":1,_id:0})

11) Remove Science column/field for Raam

db.studentmarks.update({"name":"Raam"},{$unset:{"science_marks":88}})

12) Update John’s Math mark as 87 and English mark as 23, if john not available upsert.

db.studentmarks.insert({"name":"John","maths_marks":87,"english_marks":23})

13) Rename the english_marks column/field for John to science_marks

db.studentmarks.update({"name":"John"},{$rename:{"english_marks":"science_marks"}})

14) Remove Kumaran’s document from collection

db.studentmarks.remove({"name":"Kumaran"})

15) Find Kala’s or Aruli’s math_marks and science_marks

db.studentmarks.find({"name":"Aruli"},{"maths_marks":1,"science_marks":1}).pretty()

Sass

SASS (Syntactically Awesome Stylesheet) is a CSS pre-processor, which helps to reduce repetition with CSS. It is more stable and powerful CSS extension language that describes the style of document structurally.

Features of Sass

• It is more stable, powerful, and compatible with versions of CSS.
• It is a super set of CSS and is based on JavaScript.
• It is known as syntactic sugar for CSS, which means it makes easier way for user to read or express the things more clearly.
• It uses its own syntax and compiles to readable CSS.
• You can easily write CSS in less code within less time.
• It is an open source pre-processor, which is interpreted into CSS.

Advantages of Sass

• It allows writing clean CSS in a programming construct.
• It helps in writing CSS quickly.
• It is a superset of CSS, which helps designers and developers work more efficiently and quickly.
• As Sass is compatible with all versions of CSS, we can use any available CSS libraries.
• It is possible to use nested syntax and useful functions such as color manipulation, mathematics and other values.

Converting Syntax:

# Convert Sass to SCSS
$ sass-convert style.sass style.scss

# Convert SCSS to Sass
$ sass-convert style.scss style.sass

Store data in Sass

One feature of Sass that's different than CSS is it uses variables. They are declared and set to store data, similar to JavaScript.

In JavaScript, variables are defined using the letand constkeywords. In Sass, variables start with a $followed by the variable name.

Example:

$main-fonts: Arial, sans-serif; $headings-color: green; //To use variables: h1 {   font-family: $main-fonts;   color: $headings-color; }

Nest CSS with Sass

Sass allows nesting of CSS rules, which is a useful way of organizing a style sheet.

nav {

  background-color: red;
}

nav ul {
  list-style: none;
}

nav ul li {
  display: inline-block;
}

RESPONSIVE WEB DESIGNS

JAVASCRIPT JSON

JAVASCRIPT JSON

• JSON- JavaScript Object Notation
• Which is  language independent.
• Self-describing and easy to understand
• Json is a format for storing and transporting data.
• Which is often used when data is sent from a server to a web page.
• json file type is - .json 
• json mime type is -  application/json
• Exchanging data

               -Sending data
               -Receiving data
               -Storing data
      


Syntax of JSON

•   Name/value pairs

               "name":"value"

•   Every data will separate by commas

                "name1":"value1"  ,  "name2":"value2" , "name3":"value3"

•   Objects for curly bracket

               {"name1":"value1"  ,  "name2":"value2" , "name3":"value3" }

•   Arrays for square bracket

               ["value1" , "value2" , "value3"]

Different between syntax of javascript and JSON

In javascript -  name: "value" / name: 'value'

In JSON  -  "name": "value" / "name": 'value'

JSON object

object syntax -  {"name1":"value1"  ,  "age1": 11 };

accessing object value

eg1-

var obj = {"name1":"value1"  ,  "age1": 11 };

var out = obj.name1;

document.getElementById().innerHTML=out;

eg2-

var obj = {"name1":"value1"  ,  "age1": 11 };

var out = obj["name1"];

document.getElementById().innerHTML=out;

JAVASCRIPT

  JavaScript is one of the 3 languages all web developers must learn:

   1. HTML to define the content of web pages

   2. CSS to specify the layout of web pages

   3. JavaScript to program the behavior of web pages

JavaScript is a lightweight, interpreted programming language. It is designed for creating network-centric applications. It is complimentary to and integrated with Java. JavaScript is very easy to implement because it is integrated with HTML. It is open and cross-platform.

What is JavaScript doing on your page?

Here we'll start actually looking at some code, and while doing so explore what actually happens when you run some JavaScript in your page.

Let's briefly recap the story of what happens when you load a web page in a browser (first talked about in our How CSS works article). When you load a web page in your browser, you are running your code (the HTML, CSS, and JavaScript) inside an execution environment (the browser tab). This is like a factory that takes in raw materials (the code) and outputs a product (the web page).

The JavaScript is executed by the browser's JavaScript engine, after the HTML and CSS have been assembled and put together into a web page. This ensures that the structure and style of the page are already in place by the time the JavaScript starts to run.

This is a good thing, as a very common use of JavaScript is to dynamically modify HTML and CSS to update a user interface, via the Document Object Model API (as mentioned above). If the JavaScript loaded and tried to run before the HTML and CSS was there to affect, then errors would occur.

Browser security

Each browser tab is its own separate bucket for running code in (these buckets are called "execution environments" in technical terms) — this means that in most cases the code in each tab is run completely separately, and the code in one tab cannot directly affect the code in another tab — or on another website. This is a good security measure — if this were not the case, then pirates could start writing code to steal information from other websites, and other such bad things.

Note: There are ways to send code and data between different websites/tabs in a safe manner, but these are advanced techniques that we won't cover in this course.

JavaScript running order

When the browser encounters a block of JavaScript, it generally runs it in order, from top to bottom. This means that you need to be careful what order you put things in. For example, let's return to the block of JavaScript we saw in our first example:

Here we are selecting a text paragraph (line 1), then attaching an event listener to it (line 3) so that when the paragraph is clicked, the updateName() code block (lines 5–8) is run. The updateName() code block (these types of reusable code block are called "functions") asks the user for a new name, and then inserts that name into the paragraph to update the display.

If you swapped the order of the first two lines of code, it would no longer work — instead, you'd get an error returned in the browser developer console — TypeError: para is undefined. This means that the para object does not exist yet, so we can't add an event listener to it.

Note: This is a very common error — you need to be careful that the objects referenced in your code exist before you try to do stuff to them.

Interpreted versus compiled code

You might hear the terms interpreted and compiled in the context of programming. JavaScript is an interpreted language — the code is run from top to bottom and the result of running the code is immediately returned. You don't have to transform the code into a different form before the browser runs it.

Compiled languages on the other hand are transformed (compiled) into another form before they are run by the computer. For example C/C++ are compiled into assembly language that is then run by the computer.

Both approaches have different advantages, which we won't discuss at this point.

Server-side versus client-side code

You might also hear the terms server-side and client-side code, specially in the context of web development. Client-side code is code that is run on the user's computer — when a web page is viewed, the page's client-side code is downloaded, then run and displayed by the browser. In this JavaScript module we are explicitly talking about client-side JavaScript.

Server-side code on the other hand is run on the server, then its results are downloaded and displayed in the browser. Examples of popular server-side web languages include PHP, Python, Ruby, and ASP.NET. And JavaScript! JavaScript can also be used as a server-side language, for example in the popular Node.js environment — you can find more out about server-side JavaScript in our Dynamic Websites – Server-side programming topic.

The word dynamic is used to describe both client-side JavaScript, and server-side languages — it refers to the ability to update the display of a web page/app to show different things in different circumstances, generating new content as required. Server-side code dynamically generates new content on the server, e.g. pulling data from a database, whereas client-side JavaScript dynamically generates new content inside the browser on the client, e.g. creating a new HTML table, inserting data requested from the server into it, then displaying the table in a web page shown to the user. The meaning is slightly different in the two contexts, but related, and both approaches (server-side and client-side) usually work together.

A web page with no dynamically updating content is referred to as static — it just shows the same content all the time.

 

 

 

How do you add JavaScript to your page?

JavaScript is applied to your HTML page in a similar manner to CSS. Whereas CSS uses <link> elements to apply external stylesheets and <style> elements to apply internal stylesheets to HTML, JavaScript only needs one friend in the world of HTML — the <script> element. Let's learn how this works.

Internal JavaScript

1. First of all, make a local copy of our example file apply-javascript.html. Save it in a directory somewhere sensible.
2. Open the file in your web browser and in your text editor. You'll see that the HTML creates a simple web page containing a clickable button.
3. Next, go to your text editor and add the following just before your closing </body> tag:

          

Now we'll add some JavaScript inside our <script> element to make the page do something more interesting — add the following code just below the "// JavaScript goes here" line:

Save your file and refresh the browser — now you should see that when you click the button, a new paragraph is generated and placed below.

External JavaScript

This works great, but what if we wanted to put our JavaScript in an external file? Let's explore this now.

1. First, create a new file in the same directory as your sample HTML file. Call it script.js — make sure it has that .js filename extension, as that's how it is recognized as JavaScript.
2. Next, copy all of the script out of your current <script> element and paste it into the .js file. Save that file.
3. Now replace your current <script> element with the following:
4. <script src="script.js"</script>
5. Save and refresh your browser, and you should see the same thing! It works just the same, but now we've got the JavaScript in an external file. This is generally a good thing in terms of organizing your code, and making it reusable across multiple HTML files. Plus the HTML is easier to read without huge chunks of script dumped in it.

Note: You can see this version on GitHub as apply-javascript-external.html and script.js (see it live too).

Inline JavaScript handlers

Note that sometimes you'll come across bits of actual JavaScript code living inside HTML. It might look something like this:

 

Using a pure JavaScript construct allows you to select all the buttons using one instruction. The code we used above to serve this purpose looks like this:

This might look a bit longer than the onclick attribute, but this will work for all buttons no matter how many are on the page, and how many are added or removed. The JavaScript does not need to be changed.

Note: Try editing your version of apply-javascript.html and add a few more buttons into the file. When you reload, you should find that all of the buttons when clicked will create a paragraph. Neat, huh?

As with HTML and CSS, it is possible to write comments into your JavaScript code that will be ignored by the browser, and exist simply to provide instructions to your fellow developers on how the code works (and you, if you come back to your code after 6 months and can't remember what you did). Comments are very useful, and you should use them often, particularly for larger applications. There are two types

• A single line comment is written after a double forward slash (//), e.g.

• A multi-line comment is written between the strings /* and */, e.g.

So for example, we could annotate our last demo's JavaScript with comments like so:

 

    More Learn to:

BOOTSTRAP

BOOTSTRAP

Bootstrap is a framework in css html and javascript
Bootstrap is full free to download and usage

we can download bootstrap in the screenshot's link.
which is "https://getbootstrap.com".

bootstrap downloaded css file is defending the format so if we set a class  and call that class. 

bootstrap save our time.