Open SDC File Command (Timing Analyzer)
You access this command by clicking in the Timing Analyzer.
Opens a selected Synopsys Design Constraints File (.sdc) Definition in the Intel® Quartus® Prime Text Editor or an external text editor specified on the Text Editor page of the Intel® Quartus® Prime Text Editor Options dialog box.
Note: The Timing Analyzer does not apply constraints and exceptions specified in the SDC File until you use the Read SDC File command. To re-read constraints and
exceptions from the start, use the Reset Design command, and then the Read SDC File command.