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I'll make this brief. I have to normalize this table, but the NULL entries are throwing me off.

I know {EID --> Managing Since} is a functional dependency, because EID is unique and cannot point to two different values of the same attribute.

But is {Branch Name --> Managing Since} a dependency?

Seattle points to (05/01/2007), but also points to a NULL value.
Does this mean it cannot be a dependency, as it would not have been so if it pointed to another date instead of a NULL?


The given table before any normalization
philipxy
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Ivar
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  • Please use text, not images, for text. Please research before considering asking & report it. PS There is no NULL in normalization theory. Does you "unique" mean SQL unique or math/normal unique? You need to be really clear. Including not using vague words like "point", say what you mean about values appearing with other values in rows, or sets functionally determining sets/attributes, or whatever thing(s) you mean by it. – philipxy Mar 25 '20 at 13:01
  • Does this answer your question? [What to do with null values when modeling and normalizing?](https://stackoverflow.com/questions/40733477/what-to-do-with-null-values-when-modeling-and-normalizing) – philipxy Mar 25 '20 at 13:08

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