introduce `conn.data_source_exists?` and `conn.data_sources`.

These new methods are used from the Active Record model layer to
determine which relations are viable to back a model. These new methods
allow us to change `conn.tables` in the future to only return tables and
no views. Same for `conn.table_exists?`.

The goal is to provide the following introspection methods on the
connection:

* `tables`
* `table_exists?`
* `views`
* `view_exists?`
* `data_sources` (views + tables)
* `data_source_exists?` (views + tables)

1 files changed, 2 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index feb41e96f0..79a24d1996 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -628,6 +628,7 @@ module ActiveRecord
       def tables(name = nil) # :nodoc:
         select_values("SHOW FULL TABLES", 'SCHEMA')
       end
+      alias data_sources tables
 
       def truncate(table_name, name = nil)
         execute "TRUNCATE TABLE #{quote_table_name(table_name)}", name
@@ -644,6 +645,7 @@ module ActiveRecord
 
         select_values(sql, 'SCHEMA').any?
       end
+      alias data_source_exists? table_exists?
 
       def views # :nodoc:
         select_values("SHOW FULL TABLES WHERE table_type = 'VIEW'", 'SCHEMA')