www.Senthoor.info

HTML – Introduction

Admin — Thu, 10 Jul 2008 09:53:42 +0000

Hyper Text Markup Language – HTML

Welcome to Senthoor.info’s HTML Tutorial. Here you will learn how the basics of the Hyper Text Markup Language (HTML), so that you may make your own web pages like the one you are viewing right now.
HTML is not a programming language, but rather a markup language. If you already know XML, then HTML will be a snap for you to learn. We urge you not to attempt to blow through this tutorial in one sitting. We recommend that you spend 15 minutes to an hour a day practicing HTML and then take a break, to let the information settle in. We aren’t going anywhere!

Preparation for HTML

Creating an HTML document is easy. To begin coding HTML you need only two things: a simple-text editor and the dedication to follow our tutorial! Notepad is the most basic of simple-text editors and you will probably code a fair amount of HTML with it.

If you are new to HTML and haven’t read through the Beginner’s Tutorial, please take a few minutes to complete that tutorial before moving on.

Brief HTML Background

HTML has not been around for many years. November 1990 marks the day of the first web page and back then there were little to no HTML standards to be followed. A group called the World Wide Web Consortium was then formed and have since set the standards that are widely accepted and we will base our teachings around them.

Web Pages

Web pages have many uses. Here are some important facts about why web pages are so useful.

* A cheap and easy way to spread information to a large audience.
* Another medium to market your business.
* Let the world know about you with a personal website!

Words to Know

* Tag – Used to specify (”mark-up”) regions of HTML documents for the web browser to interpret. Tags look like this:
* Element – A complete tag, having an opening and a closing .
* Attribute – Used to modify the value of the HTML element. Elements will often have multiple attributes.

For now just know that a tag is a command the web browser interprets, an element is a complete tag, and an attribute customizes or modifies HTML elements.

The Rest of the Tutorial

For the rest of the tutorial, you may use the menu to navigate to specific lessons, or you can continue to learn step-by-step using the “Continue” button below. Examples and “walk-throughs” are provided in each section.

SQL Database Glossary

Admin — Wed, 25 Jun 2008 04:17:56 +0000

Our database glossary explains common database terminology and SQL database jargon.

A

Access
Microsoft Access is an entry-level database management software from Microsoft, which allows you to organize, access, and share information easily. Access is very user-friendly and easy to use for inexperienced users, while sophisticated enough for database and software developers.

ACID
ACID short for Atomicity – Consistency – Isolation – Durability and describes the four properties of an enterprise-level transaction:

ATOMICITY: a transaction should be done or undone completely. In the event of an error or failure, all data manipulations should be undone, and all data should rollback to its previous state.
CONSISTENCY: a transaction should transform a system from one consistent state to another consistent state.
ISOLATION: each transaction should happen independently of other transactions occurring at the same time.
DURABILITY: Completed transactions should remain stable/permanent, even during system failure.

ADO
Short for Microsoft ActiveX Data Objects. ADO enables your client applications to access and manage data from a range of sources through an OLE DB provider. ADO is built on top of OLE DB and its main benefits are ease of use, high speed, and low memory overhead. ADO makes the task of building complex database enabled client/server and web applications a breeze.

B

C

Column
Database tables are made of different columns (fields) corresponding to the attributes of the object described by the table.

COMMIT
The COMMIT command in SQL marks the finalization of a database transaction.

Cursor
Short for Current Set Of Records in some database languages. The cursor is a database object pointing to a currently selected set of records.

D

Data
Piece of information collected and formatted in a specific way. The term data is frequently used to describe binary (machine-readable) information.

Database
A database is a collection of information organized into related tables of data and definitions of data objects. The data within a database can be easily accessed and manipulated trough computer program.

DB2
DB2 is a relational database management system developed by IBM. DB2 runs on a variety of platforms including Sun Solaris, Linux and Windows.

dBase
dBase is a popular relational database management system produced by Ashton-Tate corporation in the early 1980s. The dBase format for storing data has become industry standard and is still in use today.

DELETE
The DELETE is a SQL command used to delete record(s) from a table in database.

E

F

Field
See Column definition

First Normal Form
See Normalization definition

Flat File
Flat file is a data file that has no structured relationships between its records.

Foreign Key
A foreign key is a key field (column) that identifies records in a table, by matching a primary key in a different table. The foreign keys are used to cross-reference tables.

Fourth Normal Form
See Normalization definition

FoxPro
Visual FoxPro is a Microsoft development environment designed for database developers.

G

H

I

Index
An index is a database feature (a list of keys or keywords), allowing searching and locating data quickly within a table. Indexes are created for frequently searched attributes (table columns) in order to optimize the database performance.

INSERT
The INSERT is a SQL command used to add a new record to a table within a database.

Isolation
See ACID definition

J

JOIN
The JOIN is a SQL command used to retrieve data from 2 or more database tables with existing relationship based upon a common attribute.

K

Key
See Primary Key and Foreign Key definitions

L

Lock
Locks are used by Database management systems to facilitate concurrency control. Locks enable different users to access different records/tables within the same database without interfering with one another. Locking mechanisms can be enforced at the record or table levels.

M

MySQL
MySQL is an open source relational database management system. MySQL can be used on various platforms including UNIX, Linux and Windows (there are OLE DB and ODBC providers as well as .NET native provider for MySQL). MySQL is widely used as a backend database for Web applications and it’ viable and cheaper alternative to enterprise database systems like MS SQL Server and Oracle.

N

Normalization
Normalization is the process of organizing data to minimize redundancy and remove ambiguity. Normalization involves separating a database into tables and defining relationships between the tables. There are three main stages of normalization called normal forms. Each one of those stages increases the level of normalization. The 3 main normal forms are as follows:

First Normal Form (1NF): Each field in a table must contain different information.
Second Normal Form (2NF): All attributes that are not dependent upon the primary key in a database table must be eliminated.
Third Normal Form (3NF): No duplicate information is permitted. So, for example, if two tables both require a common field, this common field information should be separated into a different table.

There are 2 more normalization forms, fourth normal form (4NF) and fifth normal form (5NF), but they are rarely used. Normalization makes databases more efficient and easier to maintain.

NULL
The NULL SQL keyword is used to represent a missing value.

O

ODBC
Short for Open DataBase Connectivity, a standard database access technology developed by Microsoft Corporation. The purpose of ODBC is to allow accessing any DBMS (DataBase Management System) from any application (as long as the application and the database are ODBC compliant), regardless of which DBMS is managing the data. ODBC achieves this by using a middle layer, called a database driver, between an application and the DBMS. The purpose of this layer is to transform the application’s data queries into commands that the DBMS understands. As we said earlier, both the application and the DBMS must be ODBC compliant meaning, the application must be capable of sending ODBC commands and the DBMS must be capable of responding back to them.

OLE DB
Short for Object Linking and Embedding Data Base. OLE DB is a set of COM-based interfaces that expose data from a range of sources. OLE DB interfaces give applications standardized access to data stored in various information sources like Relational Database Management Systems (MS SQL Server, Oracle, MySQL), small personal databases like MS Access, productivity tools like spreadsheets; plain text files, etc. These interfaces support the amount of DBMS functionality appropriate to the data store, allowing the data store to share its data.

Oracle
Oracle is an enterprise relational database management system. Oracle’s main rival product MS SQL Server is a low cost alternative offering the same features.

P

PostgreSQL
PostgreSQL is an object-oriented open source relational database management system, which uses a subset of SQL language.

Primary Key
The primary key of a relational table holds a unique value, which identifies each record in the table. It can either be a normal field (column) that is guaranteed to be unique or it can be generated by the database system itself (GUID or Identity field in MS SQL Server for example). Primary keys may be composed of more than 1 field (column) in a table.

Q

Query
Queries are the main way to make a request for information from a database. Queries consist of questions presented to the database in a predefined format, in most cases SQL (Structured Query Language) format.

R

Record
The record is a complete set of information presented within a RDBMS. Records are composed of different fields (columns) in a table and each record is represented with a separate row in this table.

ROLLBACK
The ROLLBACK is a SQL command which cancels/undoes the proposed changes in a pending database transaction and marks the end of the transaction.

Row
See Record definition

S

Second Normal Form
See Normalization definition

SELECT
The SELECT is a SQL command, which is the primary means for retrieving data from a RDBMS.

SQL
SQL is short for Structured Query Language and is an industry standard language used for manipulation of data in a RDBMS. There are several different dialects of SQL like, ANSI SQL, T-SQL, etc.

Stored Procedure
Stored Procedure is a set of SQL statements stored within a database server and is executed as single entity. Using stored procedures has several advantages over using inline SQL statements, like improved performance and separation of the application logic layer from database layer in n-tier applications.

T

Table
A Table in RDBMS refers to data arranged in rows and columns, which defines a database entity.

Third Normal Form
See Normalization definition

Transaction
Transaction is a group of SQL database commands regarded and executed as a single atomic entity.

Trigger
Triggers are special type of stored procedures executed automatically when certain events take place. There are different types of triggers – for update, for insert and for delete. Each trigger is associated with a single database table.

U

UPDATE
The UPDATE is a SQL command used to edit/update existing records in a database table.

V

W

X

Y

Z

Oracle connection strings

Admin — Wed, 25 Jun 2008 04:15:03 +0000

Oracle ODBC connection strings

Open connection to Oracle database using ODBC
“Driver= {Microsoft ODBCforOracle};Server=Your_Oracle_Server.world;Uid=Your_Username;Pwd=Your_Password;”

Oracle OLE DB & OleDbConnection (.NET framework) connection strings

Open connection to Oracle database with standard security:
1. “Provider=MSDAORA;Data Source= Your_Oracle_Database;UserId=Your_Username;Password=Your_Password;”
2. “Provider= OraOLEDB.Oracle;Your_Oracle_Database;UserId=Your_Username;Password=Your_Password;”

Open trusted connection to Oracle database
“Provider= OraOLEDB.Oracle;DataSource=Your_Oracle_Database;OSAuthent=1;”

MySQL connection strings

Admin — Wed, 25 Jun 2008 04:14:21 +0000

MySQL ODBC connection strings

Open connection to local MySQL database using MySQL ODBC 3.51 Driver
“Provider=MSDASQL; DRIVER={MySQL ODBC 3.51Driver}; SERVER= localhost; DATABASE=Your_MySQL_Database; UID= Your_Username; PASSWORD=Your_Password; OPTION=3″

MySQL OLE DB & OleDbConnection (.NET framework) connection strings

Open connection to MySQL database:
“Provider=MySQLProv;Data Source=Your_MySQL_Database;User Id=Your_Username; Password=Your_Password;”

MS Access connection strings

Admin — Wed, 25 Jun 2008 04:11:15 +0000

MS Access ODBC connection strings

Standard Security:
“Driver= {MicrosoftAccessDriver(*.mdb)};DBQ=C:\App1\Your_Database_Name.mdb;
Uid=Your_Username;Pwd=Your_Password;”

Workgroup:
“Driver={Microsoft Access Driver (*.mdb)}; Dbq=C:\App1\Your_Database_Name.mdb; SystemDB=C:\App1\Your_Database_Name.mdw;”

Exclusive “Driver={Microsoft Access Driver (*.mdb)}; DBQ=C:\App1\Your_Database_Name.mdb; Exclusive=1; Uid=Your_Username; Pwd=Your_Password;”

MS Access OLE DB & OleDbConnection (.NET framework) connection strings

Open connection to Access database:
“Provider=Microsoft.Jet.OLEDB.4.0; Data Source=c:\App1\Your_Database_Name.mdb; User Id=admin; Password=”

Open connection to Access database using Workgroup (System database):
“Provider=Microsoft.Jet.OLEDB.4.0; Data Source=c:\App1\Your_Database_Name.mdb; Jet OLEDB:System Database=c:\App1\Your_System_Database_Name.mdw”

Open connection to password protected Access database:
“Provider=Microsoft.Jet.OLEDB.4.0; Data Source=c:\App1\Your_Database_Name.mdb; Jet OLEDB:Database Password=Your_Password”

Open connection to Access database located on a network share:
“Provider=Microsoft.Jet.OLEDB.4.0; Data Source=\\Server_Name\Share_Name\Share_Path\Your_Database_Name.mdb”

Open connection to Access database located on a remote server:
“Provider=MS Remote; Remote Server=http://Your-Remote-Server-IP; Remote Provider=Microsoft.Jet.OLEDB.4.0; Data Source=c:\App1\Your_Database_Name.mdb”

SQL Server connection strings

Admin — Wed, 25 Jun 2008 03:54:18 +0000

SQL ODBC connection strings

Standard Security:< br> “Driver={SQLServer};Server=Your_Server_Name;
Database=Your_Database_Name;Uid=Your_Username;Pwd=Your_Password;”

Trusted connection:< br> “Driver={SQLServer};Server=Your_Server_Name;
Database=Your_Database_Name;Trusted_Connection=yes;”

SQL OLE DB connection strings

Standard Security:
“Provider=SQLOLEDB;Data Source=Your_Server_Name;Initial Catalog= Your_Database_Name;UserId=Your_Username;Password=Your_Password;”

Trusted connection:
“Provider=SQLOLEDB;Data Source=Your_Server_Name;
Initial Catalog=Your_Database_Name;Integrated Security=SSPI;”

SQL OleDbConnection .NET strings

Standard Security:
“Provider=SQLOLEDB;Data Source=Your_Server_Name;Initial Catalog= Your_Database_Name;UserId=Your_Username;Password=Your_Password;”

Trusted connection:
“Provider=SQLOLEDB;Data Source=Your_Server_Name;
Initial Catalog=Your_Database_Name;Integrated Security=SSPI;”

SQL SqlConnection .NET strings

Standard Security:
1. “Data Source=Your_Server_Name;Initial Catalog= Your_Database_Name;UserId=Your_Username;Password=Your_Password;” < br>2. “Server=Your_Server_Name;Database=Your_Database_Name;
UserID=Your_Username;Password=Your_Password;Trusted_Connection=False”

Trusted connection:
1. “Data Source=Your_Server_Name;Initial Catalog=Your_Database_Name;Integrated Security=SSPI;”
2.”Server=Your_Server_Name;Database=Your_Database_Name;Trusted_Connection=True;”

My Play List

Admin — Tue, 20 May 2008 12:18:36 +0000

AJAX Suggest Source Code

Admin — Fri, 29 Feb 2008 03:54:15 +0000

AJAX Source Code to Suggest Example

The source code below belongs to the AJAX example on the previous page.

You can copy and paste it, and try it yourself.

The AJAX HTML Page

This is the HTML page. It contains a simple HTML form and a link to a JavaScript.


First Name:

Suggestions:

The JavaScript code is listed below.

The AJAX JavaScript

This is the JavaScript code, stored in the file “clienthint.js”:

var xmlHttp

function showHint(str)
{
if (str.length==0)
  {
  document.getElementById("txtHint").innerHTML="";
  return;
  }
xmlHttp=GetXmlHttpObject();
if (xmlHttp==null)
  {
  alert ("Your browser does not support AJAX!");
  return;
  }
var url="gethint.asp";
url=url+"?q="+str;
url=url+"&sid="+Math.random();
xmlHttp.onreadystatechange=stateChanged;
xmlHttp.open("GET",url,true);
xmlHttp.send(null);
} 

function stateChanged()
{
if (xmlHttp.readyState==4)
{
document.getElementById("txtHint").innerHTML=xmlHttp.responseText;
}
}

function GetXmlHttpObject()
{
var xmlHttp=null;
try
  {
  // Firefox, Opera 8.0+, Safari
  xmlHttp=new XMLHttpRequest();
  }
catch (e)
  {
  // Internet Explorer
  try
    {
    xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
    }
  catch (e)
    {
    xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
    }
  }
return xmlHttp;
}

The AJAX Server Page – ASP and PHP

There is no such thing as an AJAX server. AJAX pages can be served by any internet server.
The server page called by the JavaScript in the example from the previous chapter is a simple ASP file called “gethint.asp”.

Below we have listed two examples of the server page code, one written in ASP and one in PHP.

AJAX ASP Example

The code in the “gethint.asp” page is written in VBScript for an Internet Information Server (IIS). It just checks an array of names and returns the corresponding names to the client:

<%
response.expires=-1
dim a(30)
'Fill up array with names
a(1)="Anna"
a(2)="Brittany"
a(3)="Cinderella"
a(4)="Diana"
a(5)="Eva"
a(6)="Fiona"
a(7)="Gunda"
a(8)="Hege"
a(9)="Inga"
a(10)="Johanna"
a(11)="Kitty"
a(12)="Linda"
a(13)="Nina"
a(14)="Ophelia"
a(15)="Petunia"
a(16)="Amanda"
a(17)="Raquel"
a(18)="Cindy"
a(19)="Doris"
a(20)="Eve"
a(21)="Evita"
a(22)="Sunniva"
a(23)="Tove"
a(24)="Unni"
a(25)="Violet"
a(26)="Liza"
a(27)="Elizabeth"
a(28)="Ellen"
a(29)="Wenche"
a(30)="Vicky"

'get the q parameter from URL
q=ucase(request.querystring("q"))

'lookup all hints from array if length of q>0
if len(q)>0 then
  hint=""
  for i=1 to 30
    if q=ucase(mid(a(i),1,len(q))) then
      if hint="" then
        hint=a(i)
      else
        hint=hint & " , " & a(i)
      end if
    end if
  next
end if

'Output "no suggestion" if no hint were found
'or output the correct values
if hint="" then
  response.write("no suggestion")
else
  response.write(hint)
end if
%>

AJAX PHP Example

The code above rewritten in PHP.

Note: To run the entire example in PHP, remember to change the value of the url variable in “clienthint.js” from “gethint.asp” to “gethint.php”.

PHP Example

header("Cache-Control: no-cache, must-revalidate");
 // Date in the past
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");

// Fill up array with names
$a[]="Anna";
$a[]="Brittany";
$a[]="Cinderella";
$a[]="Diana";
$a[]="Eva";
$a[]="Fiona";
$a[]="Gunda";
$a[]="Hege";
$a[]="Inga";
$a[]="Johanna";
$a[]="Kitty";
$a[]="Linda";
$a[]="Nina";
$a[]="Ophelia";
$a[]="Petunia";
$a[]="Amanda";
$a[]="Raquel";
$a[]="Cindy";
$a[]="Doris";
$a[]="Eve";
$a[]="Evita";
$a[]="Sunniva";
$a[]="Tove";
$a[]="Unni";
$a[]="Violet";
$a[]="Liza";
$a[]="Elizabeth";
$a[]="Ellen";
$a[]="Wenche";
$a[]="Vicky";

//get the q parameter from URL
$q=$_GET["q"];

//lookup all hints from array if length of q>0
if (strlen($q) > 0)
{
  $hint="";
  for($i=0; $i

AJAX Suggest Example

Admin — Fri, 29 Feb 2008 03:51:38 +0000

We have seen that AJAX can be used to create more interactive applications.

AJAX Suggest Example

In the AJAX example below we will demonstrate how a web page can communicate with a web server online as a user enters data into a standard HTML form.

Type a Name in the Box Below

Suggestions:

Example Explained – The HTML Form

The form above has the following HTML code:


First Name:

Suggestions:

As you can see it is just a simple HTML form with an input field called “txt1″.

An event attribute for the input field defines a function to be triggered by the onkeyup event.

The paragraph below the form contains a span called “txtHint”. The span is used as a placeholder for data retrieved from the web server.

When the user inputs data, a function called “showHint()” is executed. The execution of the function is triggered by the “onkeyup” event. In other words: Each time the user moves his finger away from a keyboard key inside the input field, the function showHint is called.

Example Explained – The showHint() Function

The showHint() function is a very simple JavaScript function placed in the section of the HTML page.

The function contains the following code:

function showHint(str)
{
if (str.length==0)
  {
  document.getElementById("txtHint").innerHTML="";
  return;
  }
xmlHttp=GetXmlHttpObject();
if (xmlHttp==null)
  {
  alert ("Your browser does not support AJAX!");
  return;
  }
var url="gethint.asp";
url=url+"?q="+str;
url=url+"&sid="+Math.random();
xmlHttp.onreadystatechange=stateChanged;
xmlHttp.open("GET",url,true);
xmlHttp.send(null);
}

The function executes every time a character is entered in the input field.

If there is some input in the text field (str.length > 0) the function executes the following:

Defines the url (filename) to send to the server
Adds a parameter (q) to the url with the content of the input field
Adds a random number to prevent the server from using a cached file
Creates an XMLHTTP object, and tells the object to execute a function called stateChanged when a change is triggered
Opens the XMLHTTP object with the given url.
Sends an HTTP request to the server

If the input field is empty, the function simply clears the content of the txtHint placeholder.

Example Explained – The GetXmlHttpObject() Function

The example above calls a function called GetXmlHttpObject().

The purpose of the function is to solve the problem of creating different XMLHTTP objects for different browsers.

The function is listed below:

function GetXmlHttpObject()
{
var xmlHttp=null;
try
  {
  // Firefox, Opera 8.0+, Safari
  xmlHttp=new XMLHttpRequest();
  }
catch (e)
  {
  // Internet Explorer
  try
    {
    xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
    }
  catch (e)
    {
    xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
    }
  }
return xmlHttp;
}

Example Explained – The stateChanged() Function

The stateChanged() function contains the following code:

function stateChanged()
{
if (xmlHttp.readyState==4)
{
document.getElementById("txtHint").innerHTML=xmlHttp.responseText;
}
}

The stateChanged() function executes every time the state of the XMLHTTP object changes.

When the state changes to 4 (”complete”), the content of the txtHint placeholder is filled with the response text.

AJAX – The Server-Side Script

Admin — Thu, 28 Feb 2008 19:12:45 +0000

AJAX – The Server-Side ASP Script

Now we are going to create the script that displays the current server time.

The responseText property (explained in the previous chapter) will store the data returned from the server. Here we want to send back the current time. The code in “time.asp” looks like this:

<%
response.expires=-1
response.write(time)
%>

Note: The Expires property sets how long (in minutes) a page will be cached on a browser before it expires. If a user returns to the same page before it expires, the cached version is displayed. Response.Expires=-1 indicates that the page will never be cached.
Run Your AJAX Application

Try the AJAX application by typing some text into the Name text box below, then click inside the Time text box:
Name: Time:

The Time text box gets the server’s time from “time.asp” file without reloading the page!