Weak hands cannot be planted, meager skills have no foundation. Shallow wisdom is futile, how can one hope for a good name?扰扰从役倦，屑屑身事微。少壮轻年月，迟暮惜光辉。
get_table_name();
$indexable_table = $this->create_table( $table_name, [ 'id' => false ] );
$indexable_table->column(
'indexable_id',
'integer',
[
'primary_key' => true,
'unsigned' => true,
'null' => true,
'limit' => 11,
],
);
$indexable_table->column(
'ancestor_id',
'integer',
[
'primary_key' => true,
'unsigned' => true,
'null' => true,
'limit' => 11,
],
);
$indexable_table->column(
'depth',
'integer',
[
'unsigned' => true,
'null' => true,
'limit' => 11,