Hi,
in einer voll SQL-konformen Datenbank wäre das z.B. eine Anwendung für einen Check-Constraint. Leider scheitere ich dramatisch am MySQL-Manual und kann nicht rausfinden, ob sowas unterstützt wird, ich habe aber die Vermutung nein.
ALTER TABLE xyz
ADD CONSTRAINT mycheck
CHECK text IS NOT NULL OR nr IS NOT NULL
MfG
Rouven
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Computer programming is tremendous fun. Like music, it is a skill that derives from an unknown blend of innate talent and constant practice. Like drawing, it can be shaped to a variety of ends: commercial, artistic, and pure entertainment. Programmers have a well-deserved reputation for working long hours but are rarely credited with being driven by creative fevers. Programmers talk about software development on weekends, vacations, and over meals not because they lack imagination, but because their imagination reveals worlds that others cannot see. -- Larry OBrien and Bruce Eckel in Thinking in C#
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Computer programming is tremendous fun. Like music, it is a skill that derives from an unknown blend of innate talent and constant practice. Like drawing, it can be shaped to a variety of ends: commercial, artistic, and pure entertainment. Programmers have a well-deserved reputation for working long hours but are rarely credited with being driven by creative fevers. Programmers talk about software development on weekends, vacations, and over meals not because they lack imagination, but because their imagination reveals worlds that others cannot see. -- Larry OBrien and Bruce Eckel in Thinking in C#