code: def columns(table_name, name = nil)
        return false unless table_name
        schema, table = extract_schema_and_table(table_name.to_s)
        return false unless table
        schema = database_name unless schema
        @connection.columns_internal(table, nil, schema)
      end
docs: - to_sql
   ConnectionAdapters::Abstract::SchemaStatements
  - table_exists?
  - index_exists?
  - columns