Abstract: Methods for centralized access control for cloud relational database management system resources are performed by systems and devices. The methods utilize a central policy storage, managed externally to database servers, which stores external policies for access to internal database resources at up to fine granularity. Database servers in the processing system each receive external access policies that correspond to users of the system by push or pull operations from the central policy storage, and store the external access policies in a cache of the database servers for databases. For resource access, access conditions are determined via policy engines of database servers based on an external access policy in the cache that corresponds to a user, responsive to a resource access request from a device of the user specifying the internal resource. Data associated with the resource is provided to the user based on the access condition being met.

Abstract: Methods for centralized access control for cloud relational database management system resources are performed by systems and devices. The methods utilize a central policy storage, managed externally to database servers, which stores external policies for access to internal database resources at up to fine granularity. Database servers in the processing system each receive external access policies that correspond to users of the system by push or pull operations from the central policy storage, and store the external access policies in a cache of the database servers for databases. For resource access, access conditions are determined via policy engines of database servers based on an external access policy in the cache that corresponds to a user, responsive to a resource access request from a device of the user specifying the internal resource. Data associated with the resource is provided to the user based on the access condition being met.

Abstract: A series summation-calibrating device based on a semi-insulating voltage transformer includes a symmetrical high voltage test power supply, a three-port serial voltage transformer, a semi-insulating voltage transformer and an error measuring apparatus. The present invention is characterized by: a complete set of equipment for measuring the traceability of power frequency voltage ratio can be manufactured; calibrating the line according to the serial addition based on the semi-insulating voltage transformer; measuring the relative error between the three-port serial voltage transformer and the semi-insulating voltage transformer; and mathematically processing the measuring result to obtain the voltage coefficient curve of the semi-insulating voltage transformer error.