1/23/2015 UT Dallas
POEC 6382 Applied GIS Software
Modifying Record (item) in a File
UPDATE allows you to change the values of specific records for any item in the currently selected file. UPDATE first prompts you for the number of the record to update. The current item values for that record are then listed, followed by an Edit? Prompt. To change a value, type the name of the item you want to change followed by an “=“ and the new value:
Enter record number: 2 (will list current values for that record)
edit? soil_type = 30 (or soil_type = ‘clay’ if defined as character)
Enter Record Number: <return>
CALCULATE assigns new values for a data item for the currently selected records (Tables: N, I, F, B, D; INFO: I, N, D).
enter command> calculate item_name = new_value
enter command> calculate item_name_2 = item_name_1 * value
Same functionality as CALCULATE in ArcPlot. Note spaces surrounding = sign!!
MOVE assigns new data item (C) for selected records
enter command> move ‘new char string’ to item_name
enter command> move item_name_1 to item_name_2
For the same functionality in ArcPlot use MOVEITEM. (MOVE is very different in ArcPLot!)
PURGE removes all selected records from a table (but item definitions remain--handy, for example, if ADD FROM screws up, and you need to try again). KILL deletes the entire file.