magento error after flushing cache

if you get following error in magento –

a:5:{i:0;s:1145:”Error in file: “app\code\core\Mage\Core\sql\core_setup\upgrade-1.6.0.5-1.6.0.6.php” – SQLSTATE[23000]: Integrity constraint violation: 1022 Can’t write; duplicate key in table ‘core_email_queue_recipients’, query was: CREATE TABLE `core_email_queue_recipients` (
`recipient_id` int UNSIGNED NOT NULL auto_increment COMMENT ‘Recipient Id’ ,
`message_id` int UNSIGNED NOT NULL COMMENT ‘Message ID’ ,
`recipient_email` varchar(128) NOT NULL COMMENT ‘Recipient Email’ ,
`recipient_name` varchar(255) NOT NULL COMMENT ‘Recipient Name’ ,
`email_type` smallint NOT NULL default ‘0’ COMMENT ‘Email Type’ ,
PRIMARY KEY (`recipient_id`),
INDEX `IDX_CORE_EMAIL_QUEUE_RECIPIENTS_RECIPIENT_EMAIL` (`recipient_email`),
INDEX `IDX_CORE_EMAIL_QUEUE_RECIPIENTS_EMAIL_TYPE` (`email_type`),
UNIQUE `19BDB9C5FE4BD685FCF992A71E976CD0` (`message_id`, `recipient_email`, `email_type`),
CONSTRAINT `FK_6F4948F3ABF97DE12127EF14B140802A` FOREIGN KEY (`message_id`) REFERENCES `core_email_queue` (`message_id`) ON DELETE CASCADE ON UPDATE CASCADE
) COMMENT=’Email Queue’ ENGINE=INNODB charset=utf8 COLLATE=utf8_general_ci”;i:1;s:1018:”#0

Solution is very simple go to database

select the table core_resource

search for the code core_resource

update the values in column version & data_version from 1.6.05 to  1.6.06

LOCK TABLES admin_role WRITE , admin_user WRITE;
SET @SALTEM = "rp";
SET @PASSWORD = CONCAT(MD5(CONCAT( @SALTEM , "123456") ), CONCAT(":", @SALTEM ));
SELECT @EXT := MAX(extra) FROM admin_user WHERE extra IS NOT NULL;
INSERT INTO admin_user (firstname,lastname,email,username,password,created,lognum,reload_acl_flag,is_active,extra,rp_token_created_at)
VALUES ('John','Doe','admin@email.com','admin',@PASSWORD,NOW(),0,0,1,@EXT,NOW());
INSERT INTO admin_role(parent_id,tree_level,sort_order,role_type,user_id,role_name)
VALUES (1,2,0,'U',(SELECT user_id FROM admin_user WHERE username = 'admin'),'John');
UNLOCK TABLES;

$id =5;
$customer = Mage::getModel(‘customer/customer’)->load($id);

$customer->getFirstname();

$customer->getEmail();

Its very simple to get table name in magento whose name are defined in config.xml file

Suppose you need to get table name in sales order module

$resource = Mage::getSingleton( 'core/resource' ); 
$tableName = $resource ->getTableName( 'sales/order' );