each unit of data in the mtree also must describe its relationship in the overall data file e g what record tuple it is in this information according to the present invention is attached to the end node of each individual unit of data in the mtree this structure is practical to maintain because data can be added or removed from the structure inconstant time as indicated above the features of the present invention as illustrated herein for simplicity refer to ascii characters as the elements of data being processed it is to be understood however that this data element format is merely illustrative of a broad range of other data element formats such other data element formats for example include binary numbers as well as single bits fig1 illustrates the general form of a node 100 which includes an element of a data unit e g a string an integer a boolean a real number etc this node also includes a next pointer 102 and an alt pointer 104 the operation of next and alt pointers is illustrated in fig2 in reference to strings of text characters the mtree depicted describes only the following set of three strings abc ad ef more generally a string or other data unit is represented by a set of those nodes in a logically continuous path of next and alt pointers wherein the predecessor node for any alt pointer serves merely to distinguish between data units and the successor node for that alt pointer serves as a continuation on the string or other data unit a node is capable of being a next node and an alt node at the same time a specific subset of the aforementioned set is the succession.