> mentions that "Columns that are part of a PRIMARY KEY are made NOT NULL
> if not declared that way. "
> And http://dev.mysql.com/doc/mysql/en/create-table.html tells me that "A
> PRIMARY KEY is a unique KEY where all key columns must be defined as NOT
> NULL. If they are not explicitly declared as NOT NULL, MySQL declares them
> so implicitly (and silently). "
> Why is this? I actually do need NULL values (they really are not equal to
> '0', etc.), but also need this column as part of the PRIMARY key in an
> InnoDB table...
> It can't have anything to do with the 'uniqueness' of the data, since I
> have a lot of 'zero'-values in the column, as long as the combination of
> columns in the PRIMARY key results in unique values.
Ehm... it might be me - but what sense does it make to have a NULL
in a PK?
If you "need" this, then your primary key probably isn't a primary key.
Care to explain why and how you're designing your database?
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