DROP USER databasename cascade; //Oracle

It is possible to drop a database in Oracle with the new SQL statement drop database. The command gets rid of datafiles online redo log files, controlfiles and spfile.

Example to use the command

shutdown abort;
startup mount exclusive restrict;
drop database;
exit

Requirements

database must be closed,
exclusively mounted,
restricted

Oracle

In Oracle you can use the following query

select object_name from user_objects where object_type = ‘TABLE’;

MYSQL

In MySql you can use the follwing query

show tables;

Get All Schema in Oracle and MySql

ORACLE

We can get all oracle schemas using the following query

SELECT username FROM all_users;
or
SELECT * all_users;

MYSQL

We can get all mysql schemas using the following query

SELECT SCHEMA_NAME FROM information_schema.SCHEMATA;
or
SELECT * information_schema.SCHEMATA;
or
show databases

The drop database command is used when you no longer need one of the SQL databases on your server. It will remove it permanently.

Query Syntax:

drop database databasename; //mysql

Examples: If the database to be dropped is called “customer_profile”, run the following query to delete the entire database. This will remove the database ‘customer_profile’ from the MySQL server. This is irrecoverable and there is no prompting to see if you really do want to drop the database.

drop database customer_profile;

mysql

“. The program runs as a server providing multi-user access to a number of databases.

Web applications uses MySQL acts as the database component of the LAMP software stack. MySQL is used for data storage and logging of user data used by various high traffic websites includes YouTube, Nokia, Google, Wikipedia, Facebook, Flickr. It is written in C and C++.

MySQL works on many different system platforms, including AIX, BSDi, FreeBSD, HP-UX, i5/OS, Linux, Mac OS X, NetBSD, Novell NetWare, OpenBSD, OpenSolaris, eComStation, OS/2 Warp, QNX, IRIX, Solaris, Symbian, SunOS, SCO OpenServer, SCO UnixWare, Sanos, Tru64 and Microsoft Windows.
MySQL extension overview example

<?php
// Connecting, selecting database
$link = mysql_connect(‘mysql_host’, ‘mysql_user’, ‘mysql_password’)
or die(‘Could not connect: ‘ . mysql_error());
echo ‘Connected successfully’;
mysql_select_db(‘my_database’) or die(‘Could not select database’);

// Performing SQL query
$query = ‘SELECT * FROM my_table’;
$result = mysql_query($query) or die(‘Query failed: ‘ . mysql_error());

// Printing results in HTML
echo “<table>\n”;
while ($line = mysql_fetch_array($result, MYSQL_ASSOC)) {
echo “\t<tr>\n”;
foreach ($line as $col_value) {
echo “\t\t<td>$col_value</td>\n”;
}
echo “\t</tr>\n”;
}
echo “</table>\n”;

// Free resultset
mysql_free_result($result);

// Closing connection
mysql_close($link);
?>

Features and benefits of MySQL

• Massive data warehouses holding terabytes of information – Flexibility and Scalability
  Distinctive memory caches, Ultra fast load utilities, Table and Index partitioning – High Performance
  High Speed availability
  Support Multi version transaction
  High performance query engine
  Powerful authorization only access by users – Strong data protection

Lightweight Directory Access Protocol (LDAP) is an Internet protocol that email and other programs use to look up information from a server. LDAP shows a set of objects with attributes organized in a logical and hierarchical manner. In early stage LDAP is known as Lightweight Directory Browsing Protocol. It was renamed with the expansion of the range and scope of the protocol to include beyond directory browsing and searching functions also directory update functions.

For example: Telephone Directory consist of list of names arranged in an alphabetically manner with each name having an phone number and address associated with it.

Originally the protocol was created by Tim Howes of the University of Michigan, Wengyik Yeong of Performance Systems International, circa 1993 and Steve Kille of Isode Limited. LDAP current version is LDAPv3 specified in a series of Internet Engineering Task Force. Further development has come through the IETF.

Protocol Overview

A client starts an LDAP session by connecting to an LDAP server default on TCP port 389 called a Directory System Agent. The client then sends an operation request to the server, and the server sends response in return.

The client may request the following operations:

• Start Transport Layer Security (TLS) use the LDAPv3 for a secure connection
• Bind – authenticate and specify LDAP protocol version
• Search and retrieve directory entries
• Compare -test the entry contain a given attribute value in the named entry
• Add a new entry
• Delete an entry
• Modify an entry
• Modify Distinguished Name – move or rename an entry
• Abandon – abort a previous request
• Extended operation – generic operation used to define other operations
• Unbind – close the connection.

Directory structure

• A directory is a tree of directory entries
• An entry consists of a set of attributes
• An attributes or schema has a name and one or more values.
• Each entry has a unique identifier.

Representation in LDAP Data Interchange Format, an entry can look like this:

dn: cn=John Doe,dc=example,dc=com

cn: John Doe

givenName: John

sn: Doe

telephoneNumber: +1 888 555 6789

telephoneNumber: +1 888 555 1232

mail: john@example.com

manager: cn=Barbara Doe,dc=example,dc=com

objectClass: inetOrgPerson

objectClass: organizationalPerson

objectClass: person

objectClass: top

LDAP URLs format:

ldap://host:port/DN?attributes?scope?filter?extensions

For example, “ldap://ldap.example.com/cn=John%20Doe,dc=example,dc=com” refers to all user attributes in John Doe’s entry in ldap.example.com, while “ldap:///dc=example,dc=com??sub?(givenName=John)” searches for the entry in the default server.

Optimization, Backups, Replication, Load Balancing & More

In High Performance MySQL you will learn about MySQL indexing and optimization in depth so you can make better use of these key features. You will learn practical replication, backup, and load-balancing strategies with information that goes beyond available tools to discuss their effects in real-life environments. And you’ll learn the supporting techniques you need to carry out these tasks, including advanced configuration, benchmarking, and investigating logs.