A device, comprising: a processing unit; a memory coupled to the processing unit and including instructions stored thereon, the instructions, when executed by the processing unit, causing the device to perform acts for managing a co-ownership database system, the database system comprising: an underlying database for storing data of multiple members (520, 522, 524) of the database system, a rule set defining constraints on operations of the multiple members (520, 522, 524) over the database system, and a blockchain storing a record of an operation history of the database system, the acts comprising: creating an index (600, 700, 800) for the record in the blockchain; storing a copy of the index (600, 700, 800) to a timestamping service external to the database system; receiving an accessing request to the database system from a first member of the database system; verifying the accessing request based on the rule set, where the rule set is stored in the blockchain; and processing the accessing request based on a result of the verification; wherein the index (600, 700, 800) is created and the copy of it stored periodically, the copy to be used for confirming the operation history of the database system and whether an accessing request is trustworthy; in response to receiving a confirming request for confirming the accessing request, obtaining a first copy of an index (600, 700, 800) associated with the accessing request from the timestamping service; obtaining a second index (600, 700, 800) associated with the accessing request based on the blockchain; and in response to the first copy matching to the second index (600, 700, 800), confirming the accessing request as trustworthy a processing unit; a memory coupled to the processing unit and including instructions stored thereon, the instructions, when executed by the processing unit, causing the device to perform acts for managing a co-ownership database system, the database system comprising: an underlying database for storing data of multiple members (520, 522, 524) of the database system, a rule set defining constraints on operations of the multiple members (520, 522, 524) over the database system, and a blockchain storing a record of an operation history of the database system, the acts comprising: creating an index (600, 700, 800) for the record in the blockchain; storing a copy of the index (600, 700, 800) to a timestamping service external to the database system; receiving an accessing request to the database system from a first member of the database system; verifying the accessing request based on the rule set, where the rule set is stored in the blockchain; and processing the accessing request based on a result of the verification; wherein the index (600, 700, 800) is created and the copy of it stored periodically, the copy to be used for confirming the operation history of the database system and whether an accessing request is trustworthy; in response to receiving a confirming request for confirming the accessing request, obtaining a first copy of an index (600, 700, 800) associated with the accessing request from the timestamping service; obtaining a second index (600, 700, 800) associated with the accessing request based on the blockchain; and in response to the first copy matching to the second index (600, 700, 800), confirming the accessing request as trustworthy creating an index (600, 700, 800) for the record in the blockchain; storing a copy of the index (600, 700, 800) to a timestamping service external to the database system; receiving an accessing request to the database system from a first member of the database system; verifying the accessing request based on the rule set, where the rule set is stored in the blockchain; and processing the accessing request based on a result of the verification; wherein the index (600, 700, 800) is created and the copy of it stored periodically, the copy to be used for confirming the operation history of the database system and whether an accessing request is trustworthy; in response to receiving a confirming request for confirming the accessing request, obtaining a first copy of an index (600, 700, 800) associated with the accessing request from the timestamping service; obtaining a second index (600, 700, 800) associated with the accessing request based on the blockchain; and in response to the first copy matching to the second index (600, 700, 800), confirming the accessing request as trustworthy