Transitive database replication

摘要

A database is replicated to other systems using multisite table(s) and associated replication trigger logic. Each system includes a main table, multisite table(s) and replication trigger logic. A multisite table corresponds to a main table of another system. When a main table of a system is changed, in response to an input, the system generates and sends replication transactions to the other systems for changing main tables in the other systems. In accordance with the change specified in the replication transaction, the multisite tables are modified. In each system, the replication trigger logic determines whether or not to replicate the change specified in the replication transaction to the main table of the each system, upon application of the replication trigger logic to the replication transaction. The change specified in the replication transaction may relate to inserting, deleting, or updating a record in the main table.

主权项

1. A database replication method, comprising steps of:
in a first computer system, maintaining both a first main table of data for the first computer system and a first multisite table of data for a second computer system, the first multisite table of data maintaining a copy of data stored in a second main table of data on the second computer system, wherein the second computer system further includes a second multisite table of data maintaining a copy of data stored in the first main table of data of the first computer system, wherein the first main table of data and the first multisite table of data include the same types of data; in response to an input for changing the first main table of data for the first computer system:
(a) changing the first main table of data for the first computer system based on the input; and(b) sending a first replication transaction from the first computer system to the second computer system, wherein the first replication transaction indicates the change in the first main table of data for the first computer system; receiving, by the first computer system, a second replication transaction from the second computer system, the second replication transaction indicating a change in the second main table of data on the second computer system; entering the second replication transaction received from the second computer system in the first multisite table of data in the first computer system; and determining whether to replicate the entered second replication transaction into the first main table of data of the first computer system from the first multisite table of data in the first computer system, based on application of replication trigger logic to the entered second replication transaction, the replication trigger logic being stored on the first computer system and configured to compare current data in the first main table of data of the first computer system with the entered second replication transaction in the first multisite table of data in the first computer system.