Base/HSQLDB Guide 2.2
HSQLDB 2.2 User Guide
The user guide can be found here.
It should be noted that version 2.2 has not (yet) been incorporated in LibreOffice.
the original guide to make use of HSQLDB version 2.2 is here: guide HSQL 2.2 However, as stated in here integrate HSQL it is impossible to integrate HSQL 2.0 into OO/LO - by that: if you need to reuse odb-data internal OO/LO and external with HSQL, you need to strip the original HyperSQL.jar supplied with OO/LO and install that version separatly.