A method of using a database assembly, wherein the database assembly comprises: - at least three computing systems (102, 104, 106), wherein each of the at least three computing systems comprises at least one application and a local database system; - a database integration system; and - a network connection between each of the at least three computing systems and the database integration system; wherein the method comprises: • receiving a first root transaction by the local database of a first computing system, wherein the first computing system is one of the at least three computing systems, wherein the first root transaction is a database transaction generated by the at least one application of the first computing system; • executing the first root transaction on the local database of the first computing system; • generating a first link transaction by the local database of the first computing system, wherein the first link transaction is descriptive of the root transaction; • sending the first link transaction from the first computing system to the database integration system via the network connection of the first computing system; • generating a first routed transaction (134, 136) for at least one of the first remaining computing systems (104, 106) by the data base integration system, wherein the first remaining computing systems are the at least three computing systems excluding the first computing system, wherein the first routed transaction is generated using a first data mapping of the first link transaction to the local database of each of the remaining computing systems; • sending the first routed transaction to the at least one of the remaining computing systems via the network connection; and • executing the first routed transaction on the local database of the at least one of the remaining computer system. - at least three computing systems (102, 104, 106), wherein each of the at least three computing systems comprises at least one application and a local database system; - a database integration system; and - a network connection between each of the at least three computing systems and the database integration system; • receiving a first root transaction by the local database of a first computing system, wherein the first computing system is one of the at least three computing systems, wherein the first root transaction is a database transaction generated by the at least one application of the first computing system; • executing the first root transaction on the local database of the first computing system; • generating a first link transaction by the local database of the first computing system, wherein the first link transaction is descriptive of the root transaction; • sending the first link transaction from the first computing system to the database integration system via the network connection of the first computing system; • generating a first routed transaction (134, 136) for at least one of the first remaining computing systems (104, 106) by the data base integration system, wherein the first remaining computing systems are the at least three computing systems excluding the first computing system, wherein the first routed transaction is generated using a first data mapping of the first link transaction to the local database of each of the remaining computing systems; • sending the first routed transaction to the at least one of the remaining computing systems via the network connection; and • executing the first routed transaction on the local database of the at least one of the remaining computer system.