Abstract: The invention relates to a client computer for querying a database stored on a server via a network, the server being coupled to the client computer via the network, wherein the database comprises a set of first relations, wherein each first relation in the set of the first relations comprises first data items, wherein for each first relation the first data items are encrypted with a respective first cryptographic key in the first relation, wherein the first data items form a partially ordered set in each first relation, in each first relation the partial order being formed with respect to the first data items of said first relation in non-encrypted form.

Abstract: The invention relates to a client computer for querying a database stored on a server via a network, the server being coupled to the client computer via the network, wherein the database comprises first data items and suffix items, wherein each suffix item describes a suffix of at least one first data item of the first data items, wherein for each suffix item a first referential connection exists in the database assigning said suffix item to the at least one first data item comprising the suffix of said suffix item, wherein each suffix item is encrypted with a suffix cryptographic key in the database, wherein each first data item is encrypted with a first cryptographic key in the database, wherein the client computer has installed thereon an application program, the application program being operational to: receiving a search request, the search request specifying an infix search expression, said expression comprising a first wildcard term on the left side of a search criterion and a second wildcard term o

Abstract: The invention relates to a client computer for querying a database stored on a server via a network, the server being coupled to the client computer via the network, wherein the database comprises a first relation, wherein the first relation comprises first data items, wherein the first data items are encrypted with a first cryptographic key in the first relation, wherein the first data items form a partially ordered set in the first relation, the partial order being formed with respect to the first data items in non-encrypted form, wherein the client computer has installed thereon an application program, the application program being operational to perform the steps of receiving a search request specifying a search interval and determining the first data item forming an interval boundary of the search interval.

Abstract: The invention relates to a client computer for querying a database stored on a server via a network, the server being coupled to the client computer via the network, wherein the database comprises first data items and suffix items, wherein each suffix item describes a suffix of at least one first data item of the first data items, wherein for each suffix item a first referential connection exists in the database assigning said suffix item to the at least one first data item comprising the suffix of said suffix item, wherein each suffix item is encrypted with a suffix cryptographic key in the database, wherein each first data item is encrypted with a first cryptographic key in the database, wherein the client computer has installed thereon an application program, the application program being operational to: receiving a search request, the search request specifying a postfix search on a search criterion, determining the suffix item matching the search criterion, providing to the database a request for provi