Patent attributes
Methods and systems for determining one most specific row within a database table. An index includes an index structure for each column of the database table. Each index structure includes an array of pointer tuples for each value occurring in the column and a bitmap indicating cells without values. A first pointer of the tuple indicates a value and a second pointer indicates the row of the database table with the value. The index also indicates an order of specificity of the rows of the database table. A computer system processes a request by using the bitmaps of the index structures to maintain all rows of the database table without values and the pointer tuples to filter all rows of the database table that do not include the respective input value. The one row being highest in the order of specificity from the remaining rows is selected and returned.
