21. One or more non-transitory storage media as recited in claim 16 , wherein the particular portion is at least part of a first document, wherein the expression is a first expression, wherein the value is a first value, and wherein the location is a first location, wherein the instructions, when executed by the one or more computing devices, cause performance of: receiving a second expression that specifies a second value; determining that the unstructured database column in the database stores a second document, wherein the second document comprises non-marked up text that contains the specified value; determining a second location of the second document; and accessing the second document from the second location.
21. One or more non-transitory storage media as recited in claim 16 , wherein the particular portion is at least part of a first document, wherein the expression is a first expression, wherein the value is a first value, and wherein the location is a first location, wherein the instructions, when executed by the one or more computing devices, cause performance of: receiving a second expression that specifies a second value; determining that the unstructured database column in the database stores a second document, wherein the second document comprises non-marked up text that contains the specified value; determining a second location of the second document; and accessing the second document from the second location. 32. One or more non-transitory storage media as recited in claim 21 , wherein the first document and the second document are stored in the unstructured database column without indicating whether the first document conforms to the markup language, and without indicating whether the second document conforms to the markup language.