Moved exception code to the new_client method

Author: Aidan Haran

lib/active_record/connection_adapters/sqlserver_adapter.rb

@@ -63,7 +63,10 @@ class << self
         def new_client(config)
           case config[:mode]
           when :dblib
+            require "tiny_tds"
             dblib_connect(config)
+          else
+            raise ArgumentError, "Unknown connection mode in #{config.inspect}."
           end
         end
 
@@ -97,6 +100,9 @@ def dblib_connect(config)
             client.execute("SET TEXTSIZE 2147483647").do
             client.execute("SET CONCAT_NULL_YIELDS_NULL ON").do
           end
+        rescue TinyTds::Error => e
+          raise ActiveRecord::NoDatabaseError if e.message.match(/database .* does not exist/i)
+          raise e
         end
 
         def config_appname(config)

lib/active_record/sqlserver_base.rb

@@ -7,22 +7,12 @@ def sqlserver_connection(config) #:nodoc:
       config.reverse_merge!(mode: :dblib)
       config[:mode] = config[:mode].to_s.downcase.underscore.to_sym
 
-      case config[:mode]
-      when :dblib
-        require "tiny_tds"
-      else
-        raise ArgumentError, "Unknown connection mode in #{config.inspect}."
-      end
-
       ConnectionAdapters::SQLServerAdapter.new(
         ConnectionAdapters::SQLServerAdapter.new_client(config),
         logger,
         nil,
         config
         )
-    rescue TinyTds::Error => e
-      raise ActiveRecord::NoDatabaseError if e.message.match(/database .* does not exist/i)
-      raise e
     end
   end
 end