A method of storing data including the steps of providing a first index of first location identifiers, a second index of second location identifiers and a dictionary data base of data items, wherein the first location identifiers are adapted to identify the location of second location identifiers in the second index and the second location identifiers are adapted to identify the location of data items in the dictionary data base, receiving data and separating the data into a plurality of data items and storing the data items in a main data base, whereby at least one of the data items is stored in the main data base as at least one first location identifier, which identifies at least one second location identifier, which identifies the or each data item in the dictionary data base.