  The tremendous expanse of search engines, dictionary and thesaurus storage,
and other text mining applications, combined with the popularity of readily
available scanning devices and optical character recognition tools, has
necessitated efficient storage, retrieval and management of massive text
databases for various modern applications. For such applications, we propose a
novel data structure, INSTRUCT, for efficient storage and management of
sequence databases. Our structure uses bit vectors for reusing the storage
space for common triplets, and hence, has a very low memory requirement.
INSTRUCT efficiently handles prefix and suffix search queries in addition to
the exact string search operation by iteratively checking the presence of
triplets. We also propose an extension of the structure to handle substring
search efficiently, albeit with an increase in the space requirements. This
extension is important in the context of trie-based solutions which are unable
to handle such queries efficiently. We perform several experiments portraying
that INSTRUCT outperforms the existing structures by nearly a factor of two in
terms of space requirements, while the query times are better. The ability to
handle insertion and deletion of strings in addition to supporting all kinds of
queries including exact search, prefix/suffix search and substring search makes
INSTRUCT a complete data structure.
