Software Testing Methods - Grey Box Testing
Grey Box testing lies somewhere in the middle between white box testing and black box testing. It is usually a part of integration testing where testing is done software which is developed by multiple developers / software teams. These QA engineer does not have to know too much about the internal representation but they will know the limited information about the internal data representation.
QA engineer is allowed to have his own testing environment like he/she can write SQL queries that can fetch data from database server and then apply to software API calls. This process is also used in reverse engineering. When there is a N tier architecture, this testing type is very much useful.