Simplify quoting logic for generic adapter

lib/odbc_adapter/adapters/null_odbc_adapter.rb

@@ -4,6 +4,8 @@ module Adapters
     # registry. This allows for minimal support for DBMSs for which we don't
     # have an explicit adapter.
     class NullODBCAdapter < ActiveRecord::ConnectionAdapters::ODBCAdapter
+      IDENTIFIER_QUOTE_CHAR = "\"".freeze
+
       # Using the generic ToSql visitor (to attempt to get as much coverage as possible for
       # DBMSs we don't support).
       def arel_visitor
@@ -12,30 +14,21 @@ def arel_visitor
 
       def self.quote_column_name(name)
         name = name.to_s
-        quote_char = identifier_quote_char.to_s.strip
+        quote_char = IDENTIFIER_QUOTE_CHAR.to_s.strip
 
         return name if quote_char.length.zero?
         quote_char = quote_char[0]
 
         # Avoid quoting any already quoted name
         return name if name[0] == quote_char && name[-1] == quote_char
 
-        # If upcase identifiers, only quote mixed case names.
-        if upcase_identifiers?
-          return name unless name =~ /([A-Z]+[a-z])|([a-z]+[A-Z])/
-        end
+        # Only quote mixed case names since identifiers are upcase.
+        # This may cause issues with DBs that don't use upcase identifiers
+        return name unless name =~ /([A-Z]+[a-z])|([a-z]+[A-Z])/
 
         "#{quote_char.chr}#{name}#{quote_char.chr}"
       end
 
-      def self.identifier_quote_char
-        "\""
-      end
-
-      def self.upcase_identifiers?
-        true
-      end
-
       # Explicitly turning off prepared_statements in the null adapter because
       # there isn't really a standard on which substitution character to use.
       def prepared_statements