(i) Electronic wallets (e-wallets) or electronic purses allow users to make electronic transactions quickly and securely over the Internet through smartphones (or) computers.
(ii) The electronic wallet functions almost the same as a physical wallet in term that it holds our money
(iii) Electronic wallets were first recognized as a method for storing money in electronic form, and became popular because It provides a convenient way for online shopping.

Domain is a sub tree in domain name space tree structure.

Conditional statements are implemented by the following types
(i) if statement
(ii) if...else statement
(iii) if...else if... else statement
(iv) switch statement.

array(key= >value,key= >value,key= >value,etc.);
key = Specifies the key (numeric or string value = Specifies the value

Desktop publishing (abbreviated DTP) is the creation of page layouts for documents using DTP software.

Animation is the process of displaying still images with continuous movement.
Features:
(i) Screen object is a vector image.
(ii) Animation tools are very powerful and effective.
(iii) Frame rate: 16 frames/sec for smoothness impression, 25 frames/sec for natural looking.

Electronic data interchange architecture specifies four different layers namely
(i) Semantic layer
(ii) Standards translation layer
(iii) Transport layer
(iv) Physical layer

(i) Free software is a concept developed in the 1980s by an MIT computer science researcher, Richard Stallman who defined four conditions, as outlined by the nonprofit Free Software Foundation.
(ii) These "four freedoms" emphasize the ability of users to use and enjoy software as they see fit.
(iii) Freeware usually refers to proprietary software that users can download at no cost, but whose source code cannot be changed.

Post Method	Get Method
The input data sent to the server with POST method is stored in the request body of the client's HTTP request.	The input data sent to the server with POST method via URL address is known as query string. All input data are visible by user after they click the submit button.

Array is a concept that stores more than one value of same data type in single array variable.
They are 3 types of array concepts in PHP.
(i) Indexed Arrays,
(ii) Associative Array and
(iii) Multi-Dimensional Array.
Usage of Array:
When combined with foreach statement which allows loop through an array quickly with very little code.

(i) Any text (or) object that you place on the master page will appear on the entire document pages to which the master is applied.
(ii) It shortens the amount of time because you don't have to create the same objects repeatedly on subsequent pages.
(iii) Master pages commonly contain repeating logos, page numbers, headers and footers.
(iv) They also contain non-printing layout guides, such as column guides, ruler guides and margin guides.

Various file formats used in multimedia are
(i) Text formats
(ii) Image formats
(iii) Digital Audio file formats and
(iv) Digital Video file formats.
(i) Text formats : Rich Text Formats and Plain Text Format are used in Text formats.
(ii) Image formats : TIFF, BMP, DIB, GIF, JPEG, TGA, PNG are image formats.
(iii) Digital Audio file formats : WAV, MP3, OGG, AIFF, WMA and RA are Digital Audio file formats.
(iv) Digital Video file formats : AVI, MPEG are digital video file formats.

EDI was developed to solve the problems inherent in paper-based transaction processing and in other forms ofelectronic communication. Implementing EDI system offers a company greater control over its supply chain and allow it to trade more effectively. It also increases productivity and promotes operational efficiency.
The following are the other advantages of EDI.
(i) Improving service to end-users
(ii) Increasing productivity
(iii) Minimizing errors
(iv) Slashing response times
(v) Automation of operations
(vi) Cutting costs
(vii) Integrating all business and trading partners.
(viii) Providing information on process status
(ix) Optimizing financial ratios.

(i) Auction website is a kind of website, that auctions items on the Internet and levies some commission from the sales.
e.g. https://www.ebay.com/
(ii) Banner advertisement website displays advertisements of other companies in its websites and thereby earns revenue.
(iii) Bulk-buying website collect a number of users together where every one wants to buy similar items - the site negotiates a discount with the supplier and takes commission. e.g. https://www.alibaba.com/
(iv) Digital publishing sites effectively host the e-books or magazines on the web. They make profits in anumber of wayssuch as advertising, selling etc., https://wordpress.org/
(v) Licensing sites allow other websites to make use of their software. For example, the search engines which allow a visitor of the site to search within the website more easily.
(vi) Name-your-own-price websites are just like normal retail sites. In contrast, the buyer negotiates with the retailer for a particular product or service. https://in.hotels.com/
(vii) Online Shopping mall website allows multi E-Commerce traders to assemble together on a single website. Often these sellers would be related to each other, for example they may all sell luxury goods. This site would take a percentage of their profit.






 

Domain Name Space :

(i) Domain name space was designed to achieve hierarchical name space. In this, the names are represented as a tree like structure with a root element on the top and this tree can have a maximum of 128 levels starting from root element, taking level 0 to level 127
(ii) The above figure represents the domain name space where the root element is present at the top most level i.e., level 0.
(iii) The root element always represents the NULL string. The next level to the root element is node. Each node in the tree has a label and a domain name.
Label:
(i) Label is a string having a maximum of 63 characters. Each node in that level should have different labels, thereby assuring the individuality of the domain name.
(ii) In other words, Labels are the names given to domains. Domain is a sub tree in domain name space tree structure. The domain can be further divided into sub domains.
(iii) The domain name which is obtained by reading the labels from bottom to top, separating each label by dot (.).

Domain name :
(i) It is the sequence of labels. In domain name the sequence of labels are separated by dot (.).
(ii) The domain name is always read from the lower level to higher level i.e., from the leaf node to root node. Since the root node always represent NULL string, all the domain name ending with dot.

In the file handling process following task can be included
(i) open file for read and write
(ii) close file
(iii) perform operations on file
(iv) write results
With PHP we can handle file easily. There are various in built functions available for file handling for PHP.
Using file handling we can open, create, upload and edit files in PHP before working with file. We must open the file first using fopen() function.fopen() function is used in a following manner to perform this task.
＄fp = fopen(, )
In the above code, we have used two parameters while using fopen() function.
filename to open mode in which file is to be opened.
The function will return a file pointer if the file is successfully opened, otherwise it will return false.
Modes we use in the file handling

Mode	Description
r	Read only mode
r+	Read and write mode
W	Write mode only
W+	Write and read model
a	Append file mode
a+	Read and append mode
x	It used to create and open a file only for writing purpose.

ER Modeling basic concepts: The basic concepts of ER model consists of
1. Entity or Entity type
2. Attributes
3. Relationship
(i) Entity (or) Entity type
(i) An Entity can be real-world object (or) animation which is easily identifiable by anyone even by a common man.
(ii) Example: In a company's database Employee, HR, Manager are considered as entities, where each of these entity will be having their own attributes.An entity is represented by a rectangular box.

Types of Entity:
(a) Strong Entity
(b) Weak Entity
(c) Entity Instance
(i) Strong Entity
1. Strong entity is not depend on other entity and it will have a primary key.
2. It is represented by one rectangle.

3. For Example Roll Number. Everyone Roll Number varies and it will not be same.
(ii) Weak Entity
1. A weak entity is dependent on other entities and it doesn't have any primary key like strong entity.
2. It is represented by double rectangle.

3. For Example, "Marks" is the weak entity and there is no primary key or unique id. It is depend on the existence of the other entity.

(iii) Entity Instance
1. Instances are the values for the entity. So an Entity Instance denotes the category values for the given entity.
Entities Instances

Entities	Instances
Human	Male, Female
Animals	Dog, cats, lion
Jobs	Engineer, Doctor, Lawyer
Actors	Ajith, Vijay, Vikram
Electronics	Laptop, Mobile

2. Attributes
An attribute is the information about that entity and it will entity describe, quantity, qualify, classify and specify and entity. An attribute will always have a single value, that value can be a number or character or string.
Types of attributes :
(i) Key Attribute
(ii) Simple Attributes
(ii) Composite Attributes
(iv) Single Valued Attribute
(v) Multi Valued Attribute
3. Relationship Type
In ER Model, relationship exists between two entities. Three types of relationships are available and the Entity-Relationship (ER) diagram is based on the three types listed below
(i) One-to-One relationship: Consider two entities A and B. One-to-one (1:1) relationship is said to exist in a relational database design, if 0 or 1 instance of entity A is associated with 0 or 1 instance of entity B, and 0 or 1 instance of entity B is associated with 0 or I instance of entity A.
(ii) One-to-Many relationship: Consider two entities A and B. One-to-many (1:N) relationship is said to exist in a relational database design, for 1 instance of entity A there exists 0 or 1 or many instances of entity B, but for 1 instance of entity B there exists 0 ur 1 instance of entity A.
(iii) Many-to-Many relationship: Consider two entities A and B. many-to-many (M:N) relationship is said to exist in a relational database design, for 1 instance of entity A there exists 0 or 1 or many instances of entity B, and for 1 instance of entity B there exists 0 or 1 or many instance of entity A.
In reality one-to-one are in less usage, where as one-to-many and many-to-many are commonly used. However in relational database, many-to-many are converted into one-to-many relationships.