<extra foo="bar" hello="world" bar="baz" />
</constraint>
<constraint name="emailuniqueindex" type="UNIQUE" fields="email" />
+ <constraint name="very_long_index_name_on_title_field_which_should_be_truncated_for_various_rdbms" type="UNIQUE" fields="title" />
<constraint name="" type="FOREIGN KEY" fields="another_id"
reference_table="Another" options="" deferrable="1" match_type=""
expression="" on_update="" on_delete="">