A computer-implemented method for customization of a computer system, the customization having multiple customization dimensions, each dimension having an assigned data structure stored in a database system, each of the data structures being a rooted tree (120, 133) of a set of first trees, each child node in a first tree (126; 131, 132) having only one parent node (125; 130), each root node in a first tree having assigned a global customization specification for the customization dimension to which the each root node is assigned, and tuples of nodes of the rooted trees, each, having assigned a differential customization specification, each tuple comprising at least one child node of any of the rooted trees, the tuples defining a second rooted tree, wherein a pair of nodes in the second rooted tree are linked by a parent-child relationship when their tuples differ in one element only and the differing element of the parent node of the pair is a parent node in the respective first tree, wherein each node of the first trees has a context value assigned to one of the customization dimensions, wherein each of the global customization specifications comprises a respective configuration data and a respective list of software modules to be installed on the computer system using the configuration data comprised in the each of the global customization specifications, wherein each of the differential customization specifications comprises a respective second list of software modules to be deactivated in a software code installed on the computer system, a respective configuration data, and a respective first list of the software modules to be added, according to the configuration data of the each of the differential customization specifications, to the software code after the software modules of the second list of the each of the differential customization specifications are deactivated in the software code, the method comprising: • receiving by the database system a request specifying a context value for at least some of the customization dimensions; • performing by the database system a tree traversal of the second rooted tree according to the request for those of the customization dimensions for which the context value is specified in the request, wherein the performing by the database system a tree traversal of the second rooted tree comprises selecting a chain of nodes of the second rooted tree comprising a root node of the second rooted tree; • generating by the database system a customization specification for the system, wherein the customization specification is a sequence of customization procedures, wherein the first customization procedure in the sequence is to be executed using the global customization specifications for which the tree traversal of the second rooted tree has been performed, wherein the second customization procedure in the sequence is to be executed using the differential customization specification assigned to the node in the chain of nodes having the parent node being the root node of the second rooted tree, wherein each next customization procedures in the sequence, if any, is to be executed using the differential customization specification assigned to each subsequent node in the chain of nodes of the second rooted tree; and • customizing the computer system according to the generated customization specification. • • receiving by the database system a request specifying a context value for at least some of the customization dimensions; • performing by the database system a tree traversal of the second rooted tree according to the request for those of the customization dimensions for which the context value is specified in the request, wherein the performing by the database system a tree traversal of the second rooted tree comprises selecting a chain of nodes of the second rooted tree comprising a root node of the second rooted tree; • generating by the database system a customization specification for the system, wherein the customization specification is a sequence of customization procedures, wherein the first customization procedure in the sequence is to be executed using the global customization specifications for which the tree traversal of the second rooted tree has been performed, wherein the second customization procedure in the sequence is to be executed using the differential customization specification assigned to the node in the chain of nodes having the parent node being the root node of the second rooted tree, wherein each next customization procedures in the sequence, if any, is to be executed using the differential customization specification assigned to each subsequent node in the chain of nodes of the second rooted tree; and • customizing the computer system according to the generated customization specification. •