A fiber-optic surveillance system includes a fiber-optic sensor comprising a serial array of fiber-optic point-sensors, successive point-sensors being linked by a distributed fiber-optic sensor. For a distinct count query of an identifier of a detail table, where the query specifies zero or more restrictions, an aggregate table associated with the detail table is identified. A clearance r is provided between the discharge cell C1 and the addressing discharge cell C2 for communication between the cells C1 and C2. The final conformation of the cells and the structure is obtained by applying a second pressure cycle in the cells and on the inner face of the stack.