A method, apparatus, and article of manufacture for accessing data in a computer system. Compression and decompression functions are associated with a column of the table, in order to perform compression of decimal, numeric or date data stored in the column when the data is inserted or updated in the table, and in order to perform decompression of the data stored in the column when the data is retrieved from the table. The compression function compresses and stores the data in a fixed-length compressed field in the column without a length value, and the fixed-length compressed field has a size that is determined by a range of values for the data stored in the fixed-length compressed field. The decompression function retrieves and decompresses the data from the fixed-length compressed field.