Performing field calculations is an easy way to batch update many records at once in your table. The Field Calculator works on string, number, and date fields and automatically calculates selected records if the layer or table has a selection set present.
- Start an edit session. You can make calculations without being in an editing session; however, in that case, there is no way to undo the results.
- Right-click the layer or table you want to edit and open its table.
- Right-click the field heading for which you want to make a calculation and click Field Calculator.
- Use the Fields list and Functions to build a calculation expression. You can also edit the expression in the text area or type a value for the field.
- Click OK.