Check for violation of a not-null constraint
Data frame representing a table of a data base.
Names of the colum(s) of
TRUE if the check was passed successfully and
The function tests for the occurrence of
NA in any of the
x specified in
cols. Hence, it is assumed that
missing values are marked as
NA (instead of
NULL like in
a true SQL data base).
David Kneis firstname.lastname@example.org
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