Error Establishing database Connection

when i open a my website deepanker.in It shows a page error establishing a databse connection.
and when i try to got o wp-admin on same one it says repair tables and gives the errors as below:
wp_715users: Table ‘chawla_wp715.wp_715users’ doesn’t exist
wp_715comments: Table ‘chawla_wp715.wp_715comments’ doesn’t exist
wp_715links: Table ‘chawla_wp715.wp_715links’ doesn’t exist
wp_715options: Table ‘chawla_wp715.wp_715options’ doesn’t exist
wp_715commentmeta: Table ‘chawla_wp715.wp_715commentmeta’ doesn’t exist