1. A digital telecommunication system having: a switching unit; an administration and maintenance unit connected to the switching unit and into which administration and maintenance jobs are input via an administration and maintenance terminal equipment; at least one peripheral job-oriented function unit; a central system computer in the switching unit and decentralized system computers in the administration and maintenance unit and in the at least one peripheral job-oriented function unit; means for providing a system administration and maintenance computer program that has program modules for a respectively autonomous processing of the administration and maintenance jobs; a plurality of database means respectively allocated to the switching unit and to the at least one peripheral job-oriented function unit whereby the plurality of data base means have different hierarchy levels such that for modification of system configuration data sets that are stored in at least two of the plurality of database means and that are to be kept data-consistent system-wide, the respective system configuration data set in a first database means of the at least two database means having a higher-ranking hierarchy level is modified in a first modification step and the system configuration data set in a second database means of the at least two database means having a next lower-ranking hierarchy level is modified in a second modification step, comprising: a first table means having allocation data that indicates allocation between the plurality of database means and program modules that cause the central system computer to modify system configuration data sets that are stored in at least one of the database means, wherein the system configuration data sets are kept respectively consistent; a plurality of second table means respectively allocated to the switching unit and the at least one peripheral job-oriented function unit, said plurality of second table means indicating the program modules that modify the system configuration data sets that are stored in one database means of the plurality of database means and that are stored in at least one further database means of the plurality of database means for assuring data consistency; and the first table means and the plurality of second table means each containing an additional first datum for every program module, said additional first datum indicating a database means of a higher-ranking hierarchy level as compared to at least one database means of a subordinate hierarchy level.