CH8 Connecting Web Apps to Database

Question 1

Data

Answer 1

–data is the plural of the word datum which is synonymous to information.
–It includes any attributes related to any object.
–e.g. height and weight are some attributes related to you and a form of data

Question 2

Database

Answer 2

1. refers to a systematic collection of data
2. information is organized in such a way that makes data management easy

Question 3

DBMS

Answer 3

Database Management System (DBMS) is a collection of programs which enables the users to access the database, manipulate data, and help in the representation of data.

It was first implemented by Charles Bachman in 1960s.

Question 4

What are the types of DBMS?

Answer 4

1. Hierarchical DBMS
2. Network DBMS
3. Relational DBMS
4. Object Oriented Relational DBMS

Question 5

Hierarchical DBMS

Answer 5

1. shows a parent-child relationship of storing data
2. not in use nowadays
3. its structure is like a tree with nodes representing records and branches representing fields

Question 6

Network DBMS

Answer 6

1. supports many-to-many relationships
2. results in a complex database structure
3. e.g. dm server

Question 7

Relational DBMS

Answer 7

–database relationships are portrayed in the form of tables, also called relations
–pre-defined data types are supported
–most popular DBMS type used worldwide
–e.g. MySQL, Oracle and Microsoft SQL server

Question 8

Object-Oriented Relational DBMS

Answer 8

1. supports the storage of new data types
2. data is stored in the database in the form of objects
   e.g. PostgreSQL

Question 9

SQL

Answer 9

1. the user may extract data from the database using a web app
2. the web app therefore needs to communicate with the database
3. this 2-way communication is possible through a language called SQL.

Question 10

mysqli_connect

Answer 10

Connects the web app to the MySQL server

$con=mysqli_connect(“localhost”,”USERNAME”,””);

Question 11

mysqli_select_db

Answer 11

Sets an active connection with the database

mysqli_select_db($con,”DATABASE NAME”);

Question 12

mysqli_query

Answer 12

executes the query
$data=mysqli_query($sqlquery);

Question 13

mysqli_fetch_row

Answer 13

fetches the record from the table

$result=mysql_query($con,$sqlquery);
$row=mysqli_fetch_row($result);

Question 14

Write down the main steps in connecting the web app to the database to obtain result from the table.

Answer 14

1. creating a connection with the MySQL server

$con=mysqli_connect (“localhost”, “USERNAME”, “”);

2. creating an active connection with the database

mysqli_select_db ($con, “DATABASE NAME”);

3. Creating an SQL query to fetch data from the table

$sqlquery=”select * from details where rollno=$rollno”;

4. Executing the query

$data=mysqli_query($sqlquery);

5. Displaying the query result

$result=mysqli_query($con, $sqlquery);
$row=mysqli_fetch_row($result);