1. A method for improving the performance of managing data over a network by using a processor device, included with one or more network computers, to perform actions, comprising: providing source data from one or more separate data sources to the one or more network computers; providing a plurality of particular types of indices that are separate and optimized for one or more different content-types, wherein the particular types of indices include one or more of n-gram indices, temporal indices, or geo-spatial indices; generating a raw data graph from the source data, wherein the structure of the raw data graph is based on the structure of the source data; mapping one or more elements of the raw data graph to a concept graph; generating one or more concept instances based on at least the concept graph, the raw data graph, and the source data; generating one or more model-identifiers (MIDs) that correspond to the one or more concept instances, wherein the one or more MIDs include at least a path in the concept graph and one or more value keys that correspond to one or more portions of the source data; indexing values from the source data that correspond to the one or more MIDs in the one or more indices that are selected from the plurality of indices based on a content-type of the source data that is associated with the one or more MIDs; and responsive to a query, generating a result set that includes one or more result MIDs based on one or more indices of the plurality of indices, wherein a content-type of at least one portion of the query is employed to select the one or more indices used to generate the result set.