package is specifically named 'mysql_client' not in relation to the client package name parameter.

manifests/db.pp

@@ -43,10 +43,6 @@ define mysql::db (
   $enforce_sql = false,
   $ensure      = 'present'
 ) {
-  #prereqs
-  include mysql
-
-  $client_package_name = $mysql::client_package_name
   #input validation
   validate_re($ensure, '^(present|absent)$',
   "${ensure} is not supported for ensure. Allowed values are 'present' and 'absent'.")
@@ -55,7 +51,7 @@ define mysql::db (
     ensure   => $ensure,
     charset  => $charset,
     provider => 'mysql',
-    require  => [Class['mysql::server'],Package[$client_package_name]],
+    require  => [Class['mysql::server'],Package['mysql_client']],
     before   => Database_user["${user}@${host}"],
   }