13. A data processing system, comprising: one or more processors; a collection of data; at least one expanded term repository; and an executable component configured to: obtain a relational database query containing at least one condition for searching at least one field of the data repository, wherein the at least one condition includes at least one base search term providing a keyword to search for in an unstructured text field of the data repository; determine one or more parameters specifying at least a credential associated with the user and a role associated with the user; provide a plurality of sets of expanded search terms for the base search term, each set corresponding to a different level of expansion of a plurality of levels of expansions ranging from a lowest level of expansion to a highest level of expansion, and each set comprising all expanded search terms from any lower level of expansion; identify, based on the base search term and the one or more parameters, a set of expanded terms associated with the base search term, wherein identifying the set of expanded search terms comprises selecting a set of expanded search terms from the plurality of sets of expanded search terms; generate a pointer to the identified set of expanded search terms; and prior to executing the relational database query, modify the relational database query to contain one or more conditions based on one or more expanded search terms retrieved using the pointer.
13. A data processing system, comprising: one or more processors; a collection of data; at least one expanded term repository; and an executable component configured to: obtain a relational database query containing at least one condition for searching at least one field of the data repository, wherein the at least one condition includes at least one base search term providing a keyword to search for in an unstructured text field of the data repository; determine one or more parameters specifying at least a credential associated with the user and a role associated with the user; provide a plurality of sets of expanded search terms for the base search term, each set corresponding to a different level of expansion of a plurality of levels of expansions ranging from a lowest level of expansion to a highest level of expansion, and each set comprising all expanded search terms from any lower level of expansion; identify, based on the base search term and the one or more parameters, a set of expanded terms associated with the base search term, wherein identifying the set of expanded search terms comprises selecting a set of expanded search terms from the plurality of sets of expanded search terms; generate a pointer to the identified set of expanded search terms; and prior to executing the relational database query, modify the relational database query to contain one or more conditions based on one or more expanded search terms retrieved using the pointer. 16. The system of claim 13 , wherein the at least one expanded term repository comprises a single repository containing different sets of expanded search terms associated with the same base term.