1. A method of maintaining a symbol table only data structure, the method comprising: detecting a change in data associated with the symbol table only data structure; wherein the symbol table only data structure is generated for at least one column in a database table without generating a corresponding vector data structure from an encoded vector index; wherein the detected change results from a change to a first row or a last row or an occurrence count of at least one key value in the symbol table only data structure; updating the symbol table only data structure to reflect the change to the first row or the last row or occurrence count of the key value; and updating the symbol only data structure in conjunction with a detected change to an underlying database table or with a database query that references the underlying database table.