Install Magento, configure the database, report this error, all the database, database name, password are correct, but, still cannot resolve.

Mysql5.6 causes this problem.

Solutions:
More detailed visit http://www.magentocommerce.com/boards/viewthread/228456/
The problem is due to the mySQL5.6.2 deletion of the have_innoDB variable. Cause “Database Connection error” when installing Mangento1.5.
Solution: find the ‘app/code/core/Mage/Install/Model/Installer/Db. PHP’, delete or comments to the following code.
The problem was an evolution from The mysql 5.6.2 which remove ‘have_innodb variable (see http://forums.mysql.com/read.php?3415, 985).
The Magento 1.5.1 Installation wizard doesn’t work with this mysql version, retrieving all The time ‘Database Connection Error’.
For the moment, until the patch, after having checked the innodb format of your db,
you can from this file ‘app/code/core/Mage/Install/Model/Installer/db. PHP’, remove the following code:

// check InnoDB support
/* if (! Isset ($variables [‘ have_innodb ‘]) | | $variables [‘ have_innodb ‘]! = ‘YES’) {
Mage:: Mage::helper(‘ install ‘)-> __ (‘ the Database server does not support the InnoDB storage engine. ‘));
}*/