Patent ID: 8601026

Claim:
A data management device storing data, managing a plurality of users as a group and opening the data to a user who belongs to a designated group, the data management device comprising: an association setting unit configured to set association between first data which is previously set to be opened by a first user and at least one of second data; a determination unit configured to determine, from a plurality of first groups to which the first data is set to be opened, at least one group in common with one or more groups to which the first user setting association belongs; and an opening unit configured to open the second data to a second user belonging to the at least one group in common determined by the determination unit, after the association setting is performed by the setting unit, wherein the association setting unit is configured to set the at least one group in common determined by the determination unit as a group to which the second data is set to be opened, such that the second user belonging to the at least one group in common is allowed to open the second data, and wherein determination of the at least one group in common by the determination unit, and setting of the at least one group in common by the association setting unit as the group to which the second data is set to be opened, is performed upon opening of the first data by the first user, such that updating of the at least one group in common between openings of the first data by the user is avoided.