Distributed type of database system, consistency managing method for the same, and a computer-readable recording medium with a program for making a computer execute each step of the method stored therein

A consistency managing method for a distributed type of database system, which database system has a plurality of first sites each having copied data for an arbitrary object therein and a second site, different from the first sites, and configured to centrally manage consistency of copied data distributed among said first sites according to management information for managing the object, said method comprising:

• an updating permission requesting step of generating, when a transaction is generated in one of said first sites, updating permission request information including information after updating for at least one object for which copied information is required to be updated, and transmitting the generated updating permission request information to said second site;
• an updating permission determining step of receiving the updating permission request information transmitted in the updating permission requesting step by said second site and determining whether management information for the object is allowed to be updated or not according to the received updating permission request information as well as to management information for the object;
• an updating permission/inhibition information generating step of updating, when it is determined in the updating permission determining step that management information for the object is allowed to be updated, management information for the object, generating updating permission information including information for the object after updating, and also generating, when it is determined in the updating permission determining step that the management information is not allowed to be updated, updating inhibition information;
• and
• a broadcasting/distributing step of distributing the updating permission information or updating inhibition information generated in the updating permission/inhibition information generating step from said second site to said first sites in a broadcasting mode.