1. A method comprising: generating an index mapping metadata items to terms associated with the metadata items, the metadata items specifying at least structural constraints on data objects in a data repository; generating a graph describing relationships between each of the metadata items; receiving a search request comprising at least one or more search terms; based on the one or more search terms and the index, locating a candidate set of the metadata items; performing a link analysis of the graph to determine a relationship score for each particular metadata item in at least the candidate set of metadata items; for each particular metadata item in the candidate set of the metadata items, calculating a ranking score based at least on the relationship score for the particular metadata item; generating a ranked result set based on comparing the ranking scores for the candidate set of metadata items, the ranked result set including at least one metadata item in the candidate set; providing information indicating the ranked result set in response to the search request; wherein the method is performed by one or more computing devices.