PHP MySQL

What is MySQL?

  • MySQL is a database server
  • MySQL is ideal for both small and large applications
  • MySQL supports standard SQL
  • MySQL compiles on a number of platforms
  • MySQL is free to download and use

The data in MySQL is stored in database objects called tables.

A table is a collection of related data entries and it consists of columns and rows.

Database Tables

A database most often contains one or more tables. Each table is identified by a name (e.g. “Customers” or “Orders”). Tables contain records (rows) with data.

Below is an example of a table called “Persons”:

LastName FirstName Address City
3star info surat surat
php php2 php php
3starinfo mysql mysql mysql

The table above contains three records (one for each person) and four columns (LastName, FirstName, Address, and City).

Queries

A query is a question or a request.

With MySQL, we can query a database for specific information and have a recordset returned.

Look at the following query:

SELECT LastName FROM Persons

The query above selects all the data in the “LastName” column from the “Persons” table, and will return a recordset like this:

LastName
3star
php
3starinfp

Create a Connection to a MySQL Database

Before you can access data in a database, you must create a connection to the database.

In PHP, this is done with the mysql_connect() function.

Syntax

mysql_connect(servername,username,password);

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

// some code
?>

Create a Database

The CREATE DATABASE statement is used to create a database in MySQL.

Syntax

CREATE DATABASE database_name

Example

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

if (mysql_query(“CREATE DATABASE my_db”,$con))
{
echo “Database created”;
}
else
{
echo “Error creating database: ” . mysql_error();
}

mysql_close($con);
?>

Create a Table

The CREATE TABLE statement is used to create a table in MySQL.

Syntax

CREATE TABLE table_name
(
column_name1 data_type,
column_name2 data_type,
column_name3 data_type,
….

)

Insert Data Into a Database Table

The INSERT INTO statement is used to add new records to a database table.

Syntax

It is possible to write the INSERT INTO statement in two forms.

The first form doesn’t specify the column names where the data will be inserted, only their values:

INSERT INTO table_name
VALUES (value1, value2, value3,…)

The second form specifies both the column names and the values to be inserted:

INSERT INTO table_name (column1, column2, column3,…)
VALUES (value1, value2, value3,…)
Advertisements
Leave a comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s