Method and apparatus for loading data files into a data-warehouse system

A method for deciding when to overwrite an existing record in a in a data-warehouse system for which there is to be data loaded or restored for use, comprising the steps of:

• defining a relative-ordering index field for each type of record to be written to said data-warehouse system;
• defining comparison rules between the relative-ordering index fields of corresponding records to be compared to define which of the records being compared should be favored over the other in order to be written to said data-warehouse system;
• selecting at least one data source for loading into said data-warehouse system;
• querying said at least one data source to stage a record for potential loading in said data-warehouse system, wherein said staged record has data to extract for use in comparing relative-ordering indexes with any existing corresponding record in said data-warehouse system;
• if a corresponding record to said staged record does not already exist in said data-warehouse system, then writing said staged record to said data-warehouse system;
• if a corresponding record to said staged record already exists in said data-warehouse system, then comparing the relative-ordering index field for said corresponding record to the relative-ordering index field for said staged record;
• if said comparison rules favor said staged record over said corresponding record, then writing said staged record to said data-warehouse system;
• if said comparison rules favor said corresponding record over said staged record, then not overwriting said corresponding record.