1. A method for managing a change to a collection of records, the method including: maintaining the collection of records and a pending change to the collection of records in a data storage system, wherein at least some of the records each include a metadata map that maps one or more source values to one or more target values, and the pending change having been previously proposed and validated but not yet applied to the collection of records; and validating a proposed change to the collection of records specified by an input received over a user interface, the validating including: querying the data storage system based on one or more validation criteria associated with the proposed change; receiving a first result in response to the querying indicating any records in the collection of records that include information that would be affected by the proposed change; processing the pending change, the pending change being different from the proposed change; determining a second result based on the processing indicating whether or not there are any conflicting records in the pending change that represent a potential conflict with the proposed change; generating a third result based on the first result and the second result indicating any records in the collection of records or in the conflicting records that include information that would be affected by the proposed change; and processing the third result to determine whether the proposed change is valid according to the one or more validation criteria.