Improve result row detection.

Use OCI8's cursor.type to tell us if it is a select statement.

https://www.rubydoc.info/gems/ruby-oci8/OCI8/Cursor#type-instance_method

Author: andynu

lib/active_record/connection_adapters/oracle_enhanced/database_statements.rb

@@ -54,7 +54,7 @@ def raw_execute(sql, name = "SQL", binds = [], prepare: false, async: false, all
               end
 
               rows = []
-              if sql =~ /\A\s*SELECT/i # This seems a naive way to detect queries that will have row results.
+              if cursor.select_statement?
                 fetch_options = { get_lob_value: (name != "Writable Large Object") }
                 while row = cursor.fetch(fetch_options)
                   rows << row

lib/active_record/connection_adapters/oracle_enhanced/oci_connection.rb

@@ -162,6 +162,10 @@ def row_count
             @raw_cursor.row_count
           end
 
+          def select_statement?
+            @raw_cursor.type == :select_stmt
+          end
+
           def fetch(options = {})
             if row = @raw_cursor.fetch
               get_lob_value = options[:get_lob_value]