Described are techniques for maintaining the accuracy of a precomputed output by determining sets of instructions for accessing and extracting values from individual data sources used to determine the output. Responsive to the determination of a modification to data in the data source, the data sources may be accessed to determine values that may be used to modify the precomputed output. The sets of instructions for accessing the data sources may be determined based on the relationships between different data sources and between one or more data sources and the output.