A database index is a data structure that improves the speed of operations in a table. Indexes can be created using one or more columns, providing the basis for both rapid random lookups and efficient ordering of access to records.

While creating index, it should be considered that what are the columns which will be used to make SQL queries and create one or more indexes on those columns.

Practically, indexes are also type of tables, which keep primary key or index field and a pointer to each record into the actual table.

The users cannot see the indexes, they are just used to speed up queries and will be used by Database Search Engine to locate records very fast.

INSERT and UPDATE statements take more time on tables having indexes where as SELECT statements become fast on those tables. The reason is that while doing insert or update, database need to insert or update index values as well.

Simple and Unique Index

You can create a unique index on a table. A unique index means that two rows cannot have the same index value. Here is the syntax to create an Index on a table.

CREATE UNIQUE INDEX index_name ON table_name ( column1, column2,...);

You can use one or more columns to create an index. For example, we can create an index on tutorials_inf using NAME_INDEX.

CREATE UNIQUE INDEX NAME_INDEX ON tutorials_inf(name);

You can create a simple index on a table. Just omit UNIQUE keyword from the query to create simple index. Simple index allows duplicate values in a table.

If you want to index the values in a column in descending order, you can add the reserved word DESC after the column name.

mysql> CREATE UNIQUE INDEX NAME_INDEX ON tutorials_inf (name DESC);

ALTER command to add and drop INDEX

There are four types of statements for adding indexes to a table −

• ALTER TABLE tbl_name ADD PRIMARY KEY (column_list) − This statement adds a PRIMARY KEY, which means that indexed values must be unique and cannot be NULL.

• ALTER TABLE tbl_name ADD UNIQUE index_name (column_list) − This statement creates an index for which values must be unique (with the exception of NULL values, which may appear multiple times).

• ALTER TABLE tbl_name ADD INDEX index_name (column_list) − This adds an ordinary index in which any value may appear more than once.

• ALTER TABLE tbl_name ADD FULLTEXT index_name (column_list) − This creates a special FULLTEXT index that is used for text-searching purposes.

Here is the example to add index in an existing table.

mysql> ALTER TABLE tutorials_inf ADD INDEX (id);

You can drop any INDEX by using DROP clause along with ALTER command. Try out the following example to drop above-created index.

mysql> ALTER TABLE tutorials_inf DROP INDEX (c);

You can drop any INDEX by using DROP clause along with ALTER command. Try out the following example to drop above-created index.

ALTER Command to add and drop PRIMARY KEY

You can add primary key as well in the same way. But make sure Primary Key works on columns, which are NOT NULL.

Here is the example to add primary key in an existing table. This will make a column NOT NULL first and then add it as a primary key.

mysql>  ALTER TABLE tutorials_inf MODIFY id INT NOT NULL;
mysql> ALTER TABLE tutorials_inf ADD PRIMARY KEY (id);

You can use ALTER command to drop a primary key as follows:

mysql> ALTER TABLE tutorials_inf DROP PRIMARY KEY;

To drop an index that is not a PRIMARY KEY, you must specify the index name.

Displaying INDEX Information

You can use SHOW INDEX command to list out all the indexes associated with a table. Vertical-format output (specified by G) often is useful with this statement, to avoid long line wraparound −

Try out the following example

mysql> SHOW INDEX FROM table_nameG
........

Running and Shutting down MySQL Server

First check if your MySQL server is running or not. You can use the following command to check it −

ps -ef | grep mysqld

If your MySql is running, then you will see mysqld process listed out in your result. If server is not running, then you can start it by using the following command −

root@host# cd /usr/bin
./safe_mysqld &

Now, if you want to shut down an already running MySQL server, then you can do it by using the following command −

root@host# cd /usr/bin
./mysqladmin -u root -p shutdown
Enter password: ******

Setting Up a MySQL User Account

For adding a new user to MySQL, you just need to add a new entry to the user table in the database mysql.

The following program is an example of adding a new user guest with SELECT, INSERT and UPDATE privileges with the password guest123; the SQL query is −

root@host# mysql -u root -p
Enter password:*******
mysql> use mysql;
Database changed

mysql> INSERT INTO user
   (host, user, password,
   select_priv, insert_priv, update_priv)
   VALUES (''localhost'', ''guest'',
   PASSWORD(''guest123''), ''Y'', ''Y'', ''Y'');
Query OK, 1 row affected (0.20 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 1 row affected (0.01 sec)

mysql> SELECT host, user, password FROM user WHERE user = ''guest
+-----------+---------+------------------+
|    host   |   user  |     password     |
+-----------+---------+------------------+
| localhost |  guest  | 6f8c114b58f2ce9e |
+-----------+---------+------------------+
1 row in set (0.00 sec)

When adding a new user, remember to encrypt the new password using PASSWORD() function provided by MySQL. As you can see in the above example, the password mypass is encrypted to 6f8c114b58f2ce9e.

Notice the FLUSH PRIVILEGES statement. This tells the server to reload the grant tables. If you don”t use it, then you won”t be able to connect to MySQL using the new user account at least until the server is rebooted.

You can also specify other privileges to a new user by setting the values of following columns in user table to ”Y” when executing the INSERT query or you can update them later using UPDATE query.

• Select_priv
• Insert_priv
• Update_priv
• Delete_priv
• Create_priv
• Drop_priv
• Reload_priv
• Shutdown_priv
• Process_priv
• File_priv
• Grant_priv
• References_priv
• Index_priv
• Alter_priv

Another way of adding user account is by using GRANT SQL command. The following example will add user zara with password zara123 for a particular database, which is named as TUTORIALS.

root@host# mysql -u root -p password;
Enter password:*******
mysql> use mysql;
Database changed

mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP
   → ON TUTORIALS.*
   → TO ''zara''@''localhost''
   → IDENTIFIED BY ''zara123

This will also create an entry in the MySQL database table called as user.

NOTE − MySQL does not terminate a command until you give a semi colon (;) at the end of the SQL command.

The /etc/my.cnf File Configuration

In most of the cases, you should not touch this file. By default, it will have the following entries −

[mysqld]
datadir = /var/lib/mysql
socket = /var/lib/mysql/mysql.sock

[mysql.server]
user = mysql
basedir = /var/lib

[safe_mysqld]
err-log = /var/log/mysqld.log
pid-file = /var/run/mysqld/mysqld.pid

Here, you can specify a different directory for the error log, otherwise you should not change any entry in this table.

Administrative MySQL Command

Here is the list of the important MySQL commands, which you will use time to time to work with MySQL database −

• USE Databasename − This will be used to select a database in the MySQL workarea.

• SHOW DATABASES − Lists out the databases that are accessible by the MySQL DBMS.

• SHOW TABLES − Shows the tables in the database once a database has been selected with the use command.

• SHOW COLUMNS FROM tablename: Shows the attributes, types of attributes, key information, whether NULL is permitted, defaults, and other information for a table.

• SHOW INDEX FROM tablename − Presents the details of all indexes on the table, including the PRIMARY KEY.

• SHOW TABLE STATUS LIKE tablenameG − Reports details of the MySQL DBMS performance and statistics.

You have seen MySQL pattern matching with LIKE …%. MySQL supports another type of pattern matching operation based on regular expressions and the REGEXP operator. If you are aware of PHP or PERL, then it”s very simple for you to understand because this matching is very similar to those scripting regular expressions.

Following is the table of pattern, which can be used along with REGEXP operator.

Examples

Now based on above table, you can device various type of SQL queries to meet your requirements. Here, I”m listing few for your understanding. Consider we have a table called tutorials_inf and it”s having a field called name −

Query to find all the names starting with ”sa”

mysql>  SELECT * FROM tutorials_inf WHERE name REGEXP ''^sa

The sample output should be like this −

+----+------+
| id | name |
+----+------+
|  1 | sai  |
+----+------+
1 row in set (0.00 sec)

Query to find all the names ending with ”ai”

mysql> SELECT * FROM tutorials_inf WHERE name REGEXP ''ai$

The sample output should be like this −

+----+------+
| id | name |
+----+------+
|  1 | sai  |
+----+------+
1 row in set (0.00 sec)

Query to find all the names, which contain ”a”

mysql> SELECT * FROM tutorials_inf WHERE name REGEXP ''a

The sample output should be like this −

+----+-------+
| id | name  |
+----+-------+
|  1 | sai   |
|  3 | ram   |
|  4 | johar |
+----+-------+
3 rows in set (0.00 sec)

Query to find all the names starting with a vowel

mysql>  SELECT * FROM tutorials_inf WHERE name REGEXP ''^[aeiou]

Properly defining the fields in a table is important to the overall optimization of your database. You should use only the type and size of field you really need to use; don”t define a field as 10 characters wide if you know you”re only going to use 2 characters. These types of fields (or columns) are also referred to as data types, after the type of data you will be storing in those fields.

MySQL uses many different data types broken into three categories: numeric, date and time, and string types.

Numeric Data Types

MySQL uses all the standard ANSI SQL numeric data types, so if you”re coming to MySQL from a different database system, these definitions will look familiar to you. The following list shows the common numeric data types and their descriptions −

• INT − A normal-sized integer that can be signed or unsigned. If signed, the allowable range is from -2147483648 to 2147483647. If unsigned, the allowable range is from 0 to 4294967295. You can specify a width of up to 11 digits.

• TINYINT − A very small integer that can be signed or unsigned. If signed, the allowable range is from -128 to 127. If unsigned, the allowable range is from 0 to 255. You can specify a width of up to 4 digits.

• SMALLINT − A small integer that can be signed or unsigned. If signed, the allowable range is from -32768 to 32767. If unsigned, the allowable range is from 0 to 65535. You can specify a width of up to 5 digits.

• MEDIUMINT − A medium-sized integer that can be signed or unsigned. If signed, the allowable range is from -8388608 to 8388607. If unsigned, the allowable range is from 0 to 16777215. You can specify a width of up to 9 digits.

• BIGINT − A large integer that can be signed or unsigned. If signed, the allowable range is from -9223372036854775808 to 9223372036854775807. If unsigned, the allowable range is from 0 to 18446744073709551615. You can specify a width of up to 20 digits.

• FLOAT(M,D) − A floating-point number that cannot be unsigned. You can define the display length (M) and the number of decimals (D). This is not required and will default to 10,2, where 2 is the number of decimals and 10 is the total number of digits (including decimals). Decimal precision can go to 24 places for a FLOAT.

• DOUBLE(M,D) − A double precision floating-point number that cannot be unsigned. You can define the display length (M) and the number of decimals (D). This is not required and will default to 16,4, where 4 is the number of decimals. Decimal precision can go to 53 places for a DOUBLE. REAL is a synonym for DOUBLE.

• DECIMAL(M,D) − An unpacked floating-point number that cannot be unsigned. In unpacked decimals, each decimal corresponds to one byte. Defining the display length (M) and the number of decimals (D) is required. NUMERIC is a synonym for DECIMAL.

Date and Time Types

The MySQL date and time datatypes are −

• DATE − A date in YYYY-MM-DD format, between 1000-01-01 and 9999-12-31. For example, December 30th, 1973 would be stored as 1973-12-30.

• DATETIME − A date and time combination in YYYY-MM-DD HH:MM:SS format, between 1000-01-01 00:00:00 and 9999-12-31 23:59:59. For example, 3:30 in the afternoon on December 30th, 1973 would be stored as 1973-12-30 15:30:00.

• TIMESTAMP − A timestamp between midnight, January 1, 1970 and sometime in 2037. This looks like the previous DATETIME format, only without the hyphens between numbers; 3:30 in the afternoon on December 30th, 1973 would be stored as 19731230153000 ( YYYYMMDDHHMMSS ).

• TIME − Stores the time in HH:MM:SS format.

• YEAR(M) − Stores a year in 2-digit or 4-digit format. If the length is specified as 2 (for example YEAR(2)), YEAR can be 1970 to 2069 (70 to 69). If the length is specified as 4, YEAR can be 1901 to 2155. The default length is 4.

String Types

Although numeric and date types are fun, most data you”ll store will be in string format. This list describes the common string datatypes in MySQLi.

• CHAR(M) − A fixed-length string between 1 and 255 characters in length (for example CHAR(5)), right-padded with spaces to the specified length when stored. Defining a length is not required, but the default is 1.

• VARCHAR(M) − A variable-length string between 1 and 255 characters in length; for example VARCHAR(25). You must define a length when creating a VARCHAR field.

• BLOB or TEXT − A field with a maximum length of 65535 characters. BLOBs are “Binary Large Objects” and are used to store large amounts of binary data, such as images or other types of files. Fields defined as TEXT also hold large amounts of data; the difference between the two is that sorts and comparisons on stored data are case sensitive on BLOBs and are not case sensitive in TEXT fields. You do not specify a length with BLOB or TEXT.

• TINYBLOB or TINYTEXT − A BLOB or TEXT column with a maximum length of 255 characters. You do not specify a length with TINYBLOB or TINYTEXT.

• MEDIUMBLOB or MEDIUMTEXT − A BLOB or TEXT column with a maximum length of 16777215 characters. You do not specify a length with MEDIUMBLOB or MEDIUMTEXT.

• LONGBLOB or LONGTEXT − A BLOB or TEXT column with a maximum length of 4294967295 characters. You do not specify a length with LONGBLOB or LONGTEXT.

• ENUM − An enumeration, which is a fancy term for list. When defining an ENUM, you are creating a list of items from which the value must be selected (or it can be NULL). For example, if you wanted your field to contain “A” or “B” or “C”, you would define your ENUM as ENUM (”A”, ”B”, ”C”) and only those values (or NULL) could ever populate that field.

To begin with, the table creation command requires the following details −

• Name of the table
• Name of the fields
• Definitions for each field

Syntax

Here is a generic SQL syntax to create a MySQL table −

CREATE TABLE table_name (column_name column_type);

Now, we will create the following table in the TUTORIALS database.

create table tutorials_tbl(
   tutorial_id INT NOT NULL AUTO_INCREMENT,
   tutorial_title VARCHAR(100) NOT NULL,
   tutorial_author VARCHAR(40) NOT NULL,
   submission_date DATE,
   PRIMARY KEY ( tutorial_id )
);

Here, a few items need explanation −

• Field Attribute NOT NULL is being used because we do not want this field to be NULL. So, if a user will try to create a record with a NULL value, then MySQL will raise an error.

• Field Attribute AUTO_INCREMENT tells MySQL to go ahead and add the next available number to the id field.

• Keyword PRIMARY KEY is used to define a column as a primary key. You can use multiple columns separated by a comma to define a primary key.

Creating Tables from Command Prompt

It is easy to create a MySQL table from the mysql> prompt. You will use the SQL command CREATE TABLE to create a table.

Example

Here is an example, which will create tutorials_tbl −

root@host# mysql -u root -p
Enter password:*******
mysql> use TUTORIALS;
Database changed
mysql> CREATE TABLE tutorials_tbl(
   → tutorial_id INT NOT NULL AUTO_INCREMENT,
   → tutorial_title VARCHAR(100) NOT NULL,
   → tutorial_author VARCHAR(40) NOT NULL,
   → submission_date DATE,
   → PRIMARY KEY ( tutorial_id )
   → );
Query OK, 0 rows affected (0.16 sec)
mysql>

NOTE − MySQL does not terminate a command until you give a semicolon (;) at the end of SQL command.

Creating Tables Using PHP Script

PHP uses mysqli query() or mysql_query() function to create a MySQL table. This function takes two parameters and returns TRUE on success or FALSE on failure.

Syntax

$mysqli→query($sql,$resultmode)

Example

Try the following example to create a table −

Copy and paste the following example as mysql_example.php −

<html>
   <head>
      <title>Creating MySQL Table</title>
   </head>
   <body>
      <?php
         $dbhost = ''localhost
         $dbuser = ''root
         $dbpass = ''root@123
         $dbname = ''TUTORIALS
         $mysqli = new mysqli($dbhost, $dbuser, $dbpass, $dbname);

         if($mysqli→connect_errno ) {
            printf("Connect failed: %s<br />", $mysqli→connect_error);
            exit();
         }
         printf(''Connected successfully.<br />'');

         $sql = "CREATE TABLE tutorials_tbl( ".
            "tutorial_id INT NOT NULL AUTO_INCREMENT, ".
            "tutorial_title VARCHAR(100) NOT NULL, ".
            "tutorial_author VARCHAR(40) NOT NULL, ".
            "submission_date DATE, ".
            "PRIMARY KEY ( tutorial_id )); ";
         if ($mysqli→query($sql)) {
            printf("Table tutorials_tbl created successfully.<br />");
         }
         if ($mysqli→errno) {
            printf("Could not create table: %s<br />", $mysqli→error);
         }
         $mysqli→close();
      ?>
   </body>
</html>

Output

Access the mysql_example.php deployed on apache web server and verify the output.

Connected successfully.
Table tutorials_tbl created successfully.

To insert data into a MySQL table, you would need to use the SQL INSERT INTO command. You can insert data into the MySQL table by using the mysql> prompt or by using any script like PHP.

Syntax

Here is a generic SQL syntax of INSERT INTO command to insert data into the MySQL table −

INSERT INTO table_name ( field1, field2,...fieldN )
   VALUES
   ( value1, value2,...valueN );

To insert string data types, it is required to keep all the values into double or single quotes. For example “value”.

Inserting Data from the Command Prompt

To insert data from the command prompt, we will use SQL INSERT INTO command to insert data into MySQL table tutorials_tbl.

Example

The following example will create 3 records into tutorials_tbl table −

root@host# mysql -u root -p password;
Enter password:*******
mysql> use TUTORIALS;
Database changed

mysql> INSERT INTO tutorials_tbl
   →(tutorial_title, tutorial_author, submission_date)
   →VALUES
   →("Learn PHP", "John Poul", NOW());
Query OK, 1 row affected (0.01 sec)

mysql> INSERT INTO tutorials_tbl
   →(tutorial_title, tutorial_author, submission_date)
   →VALUES
   →("Learn MySQL", "Abdul S", NOW());
Query OK, 1 row affected (0.01 sec)

mysql> INSERT INTO tutorials_tbl
   →(tutorial_title, tutorial_author, submission_date)
   →VALUES
   →("JAVA Tutorial", "Sanjay", ''2007-05-06'');
Query OK, 1 row affected (0.01 sec)
mysql>

NOTE − Please note that all the arrow signs (→) are not a part of the SQL command. They are indicating a new line and they are created automatically by the MySQL prompt while pressing the enter key without giving a semicolon at the end of each line of the command.

In the above example, we have not provided a tutorial_id because at the time of table creation, we had given AUTO_INCREMENT option for this field. So MySQL takes care of inserting these IDs automatically. Here, NOW() is a MySQL function, which returns the current date and time.

Inserting Data Using a PHP Script

PHP uses mysqli query() or mysql_query() function to insert a record into a MySQL table. This function takes two parameters and returns TRUE on success or FALSE on failure.

Syntax

$mysqli→query($sql,$resultmode)

Example

This example will take three parameters from the user and will insert them into the MySQL table − −

Copy and paste the following example as mysql_example.php −

<html>
   <head>
      <title>Add New Record in MySQL Database</title>
   </head>
   <body>
      <?php
         if(isset($_POST[''add''])) {
            $dbhost = ''localhost
            $dbuser = ''root
            $dbpass = ''root@123
            $dbname = ''TUTORIALS
            $mysqli = new mysqli($dbhost, $dbuser, $dbpass, $dbname);

            if($mysqli→connect_errno ) {
               printf("Connect failed: %s<br />", $mysqli→connect_error);
               exit();
            }
            printf(''Connected successfully.<br />'');

            if(! get_magic_quotes_gpc() ) {
               $tutorial_title = addslashes ($_POST[''tutorial_title'']);
               $tutorial_author = addslashes ($_POST[''tutorial_author'']);
            } else {
               $tutorial_title = $_POST[''tutorial_title''];
               $tutorial_author = $_POST[''tutorial_author''];
            }
            $submission_date = $_POST[''submission_date''];
            $sql = "INSERT INTO tutorials_tbl ".
               "(tutorial_title,tutorial_author, submission_date) "."VALUES ".
               "(''$tutorial_title'',''$tutorial_author'',''$submission_date'')";

            if ($mysqli→query($sql)) {
               printf("Record inserted successfully.<br />");
            }
            if ($mysqli→errno) {
               printf("Could not insert record into table: %s<br />", $mysqli→error);
            }
            $mysqli→close();
         } else {
      ?>
      <form method = "post" action = "<?php $_PHP_SELF ?>">
         <table width = "600" border = "0" cellspacing = "1" cellpadding = "2">
            <tr>
               <td width = "250">Tutorial Title</td>
               <td><input name = "tutorial_title" type = "text" id = "tutorial_title"></td>
            </tr>
            <tr>
               <td width = "250">Tutorial Author</td>
               <td><input name = "tutorial_author" type = "text" id = "tutorial_author"></td>
            </tr>
            <tr>
               <td width = "250">Submission Date [   yyyy-mm-dd ]</td>
               <td><input name = "submission_date" type = "text" id = "submission_date"></td>
            </tr>
            <tr>
               <td width = "250"> </td>
               <td></td>
            </tr>
            <tr>
               <td width = "250"> </td>
               <td><input name = "add" type = "submit" id = "add"  value = "Add Tutorial"></td>
            </tr>
         </table>
      </form>
   <?php
      }
   ?>
   </body>
</html>

Output

Access the mysql_example.php deployed on apache web server, enter details and verify the output on submitting the form.

Record inserted successfully.

While doing a data insert, it is best to use the function get_magic_quotes_gpc() to check if the current configuration for magic quote is set or not. If this function returns false, then use the function addslashes() to add slashes before the quotes.

You can put many validations around to check if the entered data is correct or not and can take the appropriate action.

It is very easy to drop an existing MySQL table, but you need to be very careful while deleting any existing table because the data lost will not be recovered after deleting a table.

Syntax

Here is a generic SQL syntax to drop a MySQL table −

DROP TABLE table_name ;

Dropping Tables from the Command Prompt

To drop tables from the command prompt, we need to execute the DROP TABLE SQL command at the mysql> prompt.

Example

The following program is an example which deletes the tutorials_tbl −

root@host# mysql -u root -p
Enter password:*******
mysql> use TUTORIALS;
Database changed
mysql> DROP TABLE tutorials_tbl
Query OK, 0 rows affected (0.8 sec)
mysql>

Dropping Tables Using PHP Script

PHP uses mysqli query() or mysql_query() function to drop a MySQL table. This function takes two parameters and returns TRUE on success or FALSE on failure.

Syntax

$mysqli→query($sql,$resultmode)

Example

Try the following example to drop a table −

Copy and paste the following example as mysql_example.php −

<html>
   <head>
      <title>Dropping MySQL Table</title>
   </head>
   <body>
      <?php
         $dbhost = ''localhost
         $dbuser = ''root
         $dbpass = ''root@123
         $dbname = ''TUTORIALS
         $mysqli = new mysqli($dbhost, $dbuser, $dbpass, $dbname);

         if($mysqli→connect_errno ) {
            printf("Connect failed: %s<br />", $mysqli→connect_error);
            exit();
         }
         printf(''Connected successfully.<br />'');

         if ($mysqli→query("Drop Table tutorials_tbl")) {
            printf("Table tutorials_tbl dropped successfully.<br />");
         }
         if ($mysqli→errno) {
            printf("Could not drop table: %s<br />", $mysqli→error);
         }
         $mysqli→close();
      ?>
   </body>
</html>

Output

Access the mysql_example.php deployed on apache web server and verify the output.

Connected successfully.
Table tutorials_tbl dropped successfully.

Drop a Database using mysqladmin

You would need special privileges to create or to delete a MySQL database. So, assuming you have access to the root user, you can create any database using the mysql mysqladmin binary.

Be careful while deleting any database because you will lose your all the data available in your database.

Here is an example to delete a database(TUTORIALS) created in the previous chapter −

[root@host]# mysqladmin -u root -p drop TUTORIALS
Enter password:******

This will give you a warning and it will confirm if you really want to delete this database or not.

Dropping the database is potentially a very bad thing to do.
Any data stored in the database will be destroyed.

Do you really want to drop the ''TUTORIALS'' database [y/N] y
Database "TUTORIALS" dropped

Drop Database using PHP Script

PHP uses mysqli query() or mysql_query() function to drop a MySQL database. This function takes two parameters and returns TRUE on success or FALSE on failure.

Syntax

$mysqli→query($sql,$resultmode)

Example

Try the following example to drop a database −

Copy and paste the following example as mysql_example.php −

<html>
   <head><title>Dropping MySQL Database</title></head>
   <body>
      <?php
         $dbhost = ''localhost
         $dbuser = ''root
         $dbpass = ''root@123
         $mysqli = new mysqli($dbhost, $dbuser, $dbpass);

         if($mysqli->connect_errno ) {
            printf("Connect failed: %s<br />", $mysqli->connect_error);
            exit();
         }
         printf(''Connected successfully.<br />'');

         if ($mysqli->query("Drop DATABASE TUTORIALS")) {
            printf("Database TUTORIALS dropped successfully.<br />");
         }
         if ($mysqli->errno) {
            printf("Could not drop database: %s<br />", $mysqli->error);
         }
         $mysqli->close();
      ?>
   </body>
</html>

Output

Access the mysql_example.php deployed on apache web server and verify the output.

Connected successfully.
Database TUTORIALS dropped successfully.