1 files changed, 23 insertions, 5 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index a497a354f7..1cc10e3b93 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -31,6 +31,8 @@ module ActiveRecord
       # Returns the relation names useable to back Active Record models.
       # For most adapters this means all #tables and #views.
       def data_sources
+        select_values(data_source_sql, "SCHEMA")
+      rescue NotImplementedError
         tables | views
       end
 
@@ -39,12 +41,14 @@ module ActiveRecord
       #   data_source_exists?(:ebooks)
       #
       def data_source_exists?(name)
+        select_values(data_source_sql(name), "SCHEMA").any? if name.present?
+      rescue NotImplementedError
         data_sources.include?(name.to_s)
       end
 
       # Returns an array of table names defined in the database.
       def tables
-        raise NotImplementedError, "#tables is not implemented"
+        select_values(data_source_sql(type: "BASE TABLE"), "SCHEMA")
       end
 
       # Checks to see if the table +table_name+ exists on the database.
@@ -52,12 +56,14 @@ module ActiveRecord
       #   table_exists?(:developers)
       #
       def table_exists?(table_name)
+        select_values(data_source_sql(table_name, type: "BASE TABLE"), "SCHEMA").any? if table_name.present?
+      rescue NotImplementedError
         tables.include?(table_name.to_s)
       end
 
       # Returns an array of view names defined in the database.
       def views
-        raise NotImplementedError, "#views is not implemented"
+        select_values(data_source_sql(type: "VIEW"), "SCHEMA")
       end
 
       # Checks to see if the view +view_name+ exists on the database.
@@ -65,6 +71,8 @@ module ActiveRecord
       #   view_exists?(:ebooks)
       #
       def view_exists?(view_name)
+        select_values(data_source_sql(view_name, type: "VIEW"), "SCHEMA").any? if view_name.present?
+      rescue NotImplementedError
         views.include?(view_name.to_s)
       end
 
@@ -97,10 +105,12 @@ module ActiveRecord
         indexes(table_name).any? { |i| checks.all? { |check| check[i] } }
       end
 
-      # Returns an array of Column objects for the table specified by +table_name+.
-      # See the concrete implementation for details on the expected parameter values.
+      # Returns an array of +Column+ objects for the table specified by +table_name+.
       def columns(table_name)
-        raise NotImplementedError, "#columns is not implemented"
+        table_name = table_name.to_s
+        column_definitions(table_name).map do |field|
+          new_column_from_field(table_name, field)
+        end
       end
 
       # Checks to see if a column exists in a given table.
@@ -1304,6 +1314,14 @@ module ActiveRecord
         def can_remove_index_by_name?(options)
           options.is_a?(Hash) && options.key?(:name) && options.except(:name, :algorithm).empty?
         end
+
+        def data_source_sql(name = nil, type: nil)
+          raise NotImplementedError
+        end
+
+        def quoted_scope(name = nil, type: nil)
+          raise NotImplementedError
+        end
     end
   end
 end