- Number,
Royal House} In reality,
superkeys cannot be
determined simply by
examining one set of
tuples in a relation. A
superkey defines a
functional dependency...
- relation. The
superkeys of a
relation are all the
possible ways we can
identify a row. The
candidate keys are the
minimal subsets of each
superkey and as such...
- be
considered as the table's
superkeys. However, only S1, S2, S3 and S4 are
candidate keys (that is,
minimal superkeys for that relation)
because e.g...
- bag, by
violating the
basic definition of a set. Both
foreign keys and
superkeys (that
includes candidate keys) can be composite, that is, can be composed...
- ID,
Supplier ID}}. No
component of that join
dependency is a
superkey (the sole
superkey being the
entire heading), so the
table does not
satisfy the...
-
subset of X,
meaning X → Y is a
trivial functional dependency), X is a
superkey,
every element of Y \ X, the set
difference between Y and X, is a prime...
-
multivalued dependencies X ↠ {\displaystyle \twoheadrightarrow } Y, X is a
superkey—that is, X is
either a
candidate key or a su****t thereof. If the column...
- More formally, a
primary key is a
choice of
candidate key (a
minimal superkey); any
other candidate key is an
alternate key. A
primary key may consist...
-
axioms Codd's 12
rules CAP
theorem CRUD Null
Candidate key
Foreign key
Superkey Surrogate key
Unique key
Objects Relation table column row View Transaction...
-
implied by the
candidate key(s) of R if and only if each of A, B, …, Z is a
superkey for R. The
fifth normal form was
first described by
Ronald ****in in his...
