-- store all your basic details for hardware in here
create table Hardware(
   id                    varchar(20),
   name               varchar(100),
   description        varchar(255),
   hardwareType       varchar(20),
   price                float,
   supplier             varchar(20),
   ...
)

-- motherboard, case, cpu, internal disk, etc
create table HardwareType(
    hardwareType       varchar(20),
    description         varchar(255)
)

-- store standards available for each hardware type ie
-- internal disk: SATA, IDE, 3.5", 2.5" etc
create table StandardsAvailable(
    hardwareType        varchar(20),
    standardName        varchar(20)
)

-- a piece of hardware might comply with lots of standards ie
-- a particular hard disk might store: SATA and 3.5"
create table HardwareStandards(
    id                         varchar(20),
    standardName              varchar(20)
)

-- optional entries for when a particular item that normally should be
-- compatible really isn't - the relationship might be "incompatible"
-- You could have other entries for recommended etc
create table HardwareSpecialRel(
    id_main                    varchar(20),
    id_sub                     varchar(20),
    relationship                  varchar(20)
)

-- lookup ie incompatible, recommended etc
create table relationshipType(
    relationship              varchar(20)
)