Hi Al,

>>In theory the above INSERT statement should throw a foreign constraint error because when it inserts the very first record (Paul, Alice) there is no record with 'Alice' primary key.<<

This is incorrect. There is only one INSERT statement, not a series of INSERT statements. It inserts the result of a query, that just happpens to be a bunch of UNION'ed together SELECT's for constants. However, there is no theoretic difference between this INSERT and something as

  INSERT INTO Tab1 (col1, col2)

  SELECT col3, col4

  FROM Tab2

  WHERE something = something_else;

In other words - the whole set of rows returned by the SELECT statement is inserted at once, not row by row.