Instead of running an Update Query every time when you find a new atrifact, it will be a better method if you design two forms for both Site details and Artifacts Table and link them together. Do this as follows;
- Design the Main Form for the Site Table
- Design a Sub-Form in Datasheet View or Continuous Form for Artifacts Table
- Insert the Artifacts form as Sub-form into the Main Site Form
- Select the Sub-form and display its property Sheet (View- ->Properties)
- Enter the SiteID in the Link Master Field Property
- Enter the SiteID of the Artifacts Table into the Link Child Field Property and save the Form.
- Before you attempt to enter an Artifact record find the Site Name in the Main Form.
- then enter the Artificats details in the sub-form.
- The SiteId will be automatically recorded into the Artiifacts table.