The user of an application may query a data storage system with a request to access a dataset from a database of the system. The system identifies at least one data access rule that is applicable to the dataset, with the at least one data access rule specifying at least one user group authorized to access a restricted portion of the dataset. The system identifies an authorized access group associated with the application user and compares it to the at least one user group authorized to access the restricted portion of the dataset. If the authorized access group associated with the user does not match one of the at least one user group authorized to access the restricted portion of the dataset, the system assembles a modified dataset based on the dataset and the at least one data access rule and transmits the modified dataset to the application.