Emdros is my largest software project to date. It is a text database engine for analyzed or annotated text.
Emdros is best suited to linguistic analyses of text, but any text that is annotated or analyzed will likely benefit from being stored by -- and retrieved with -- Emdros.
Emdros has a powerful query-language which allows query/create/update/delete operations on the data. The query-part is particularly powerful, allowing complex searches based on not only the text and its annotations, but also the structural properties of the text in terms of embedding and sequence.
Emdros has a homepage at http://emdros.org/.