[delete db=some.db&eqNAMEdata=Fred]copy

Putting [delete db=some.db&eqNAMEdata=Fred] in your template opens the some.db database (you can specify a DatabasePath), finds all the records whose NAME field contains "Fred," and deletes those records and exclusively those records. Any valid search parameters are allowed, as defined in the [search] context.

if the database has username and password fields, then the records will not be deleted unless the visitor's web browser username/password match the record's username/password.

You can specifiy a WebDNA table, in place of a db file.
For example: [delete table=TableName&...].