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no they did not
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What is minimal key?
no they did not
Can Super key be null?
why there is no answer yet
What is a super key in database?
S a subset of A, is a super key if S -> A. That is, the combination of all attributes in S, determines all attributes in A. Example: R(studentNo, firstName, lastName, course, instructor) FDs: studentNo -> firstName, lastName, course course -> instructor Is studentNo a super key? Yes, because studentNo yields the attributes firstName, lastName and course and course yield instructor. So with studentNo as super key, we are able to retrieve all the other attributes in relation R. Is course a super key? No, because we can only retrieve the instructor attribute and nothing else.
What is the difference between a key and a superkey in DBMS?
I am supposing that key means primary key.Superkey is any subset of attributes that uniquely identifies the tuples of a relation. This subset need not be minimal, that is, one can remove some attributes from it and it is still uniquely identifying. If all redundant attributes are removed you get a subset what is called primary key.
What is minimal normal form a relation must satisfy in dbms?
Third normal form.
What is minimal key?
no they did not
Can super key be as primary key?
I think super key is treated as the primary key because in a table their will be only one primary key.
Difference between a super key and a candidate key?
Different set of attributes which are able to identify any row in the database is known as super key. And minimal super key is termed as candidate key i.e. among set of super keys one with minimum number of attributes. Primary key could be any key which is able to identify a specific row in database in a unique manner.
Difference between super key and composite key?
A Super key and composite key are similar to one another. Both of them are used to uniquely identify a row in a database table. A super key is a set of columns within a table that can be used to identify a particular row in a table. A super key can be only one column or a combination of multiple columns. If a super key contains multiple columns it becomes a composite key.
What is the super key in database management system?
the super key is the windows key (the flag) in non-windows OS
How do you use animations on Linux without the super key?
Animations have no direct relation whatsoever to the Super key.
What are the differences between super key primary key candidate key and foreign key?
Super key: A set of attributes that uniquely identifies a tuple in a table. Primary key: A specific super key chosen to uniquely identify each tuple in a table and must be unique and not null. Candidate key: Any super key that could be chosen as the primary key. Foreign key: A field in a table that is a primary key in another table, used to establish a relationship between the two tables.
What are the difference between superkey and candidate key?
A superkey is defined as a set of attributes of a relation for which it holds that in all relations assigned to that variable there are no two distinct tuples (rows) that have the same values for the attributes in this set. As an example Code: Roll Number | First Name | Last Name CSU0001 | Shabbir | Bhimani | CSU0002 | SomeName | SurName | CSU0003 | Larry | page | Now here we have the following as super keys 1. Roll Number | First Name 2. Roll Number | First Name | Last Name Now in plain language Any Unique key with some Non Unique key combination is called a super key of the relationship. A candidate key of a relationship is a set of attributes of that relationship such that there are no two distinct tuples with the same values for these attributes. In simple example candidate key is a minimal superkey, i.e. a superkey of which no proper subset is also a superkey. Since a relation is a set(no duplicate elements), it holds that every relation will have at least one candidate key (because the entire heading is always a superkey). For practical reasons RDBMSs usually require that for each relation one of its candidate keys is declared as the primary key Quote: For example, Given an employee table consisting of the columns: employeeID name job and departmentID we could use the employeeID in combination with any or all other columns of this table to uniquely identify a row in the table. Examples of superkeys in this table would be {employeeID, Name}, {employeeID, Name, job}, and {employeeID, Name, job, departmentID}. In a real database we don't need values for all of those columns to identify a row. We only need, per our example, the set {employeeID}. This is a minimal superkey - that is, a minimal set of columns that can be used to identify a single row. So, employeeID is a candidate key. Now, if employeeID is a candidate key then why not it is the superkey. Because employeeID can also uniquely identify the tuples. (2) In your example why Roll number is not the superkey as it is uniquely identifying the tuples? (3) Quote: Any Unique key with some Non Unique key combination is called a super key of the relationship Is it necessary that Unique key has to be combined with some Non Unique key to be called as a super key. Unique key is also a super key but the minimal super key is called candidate key and all candidate keys are super keys but the reverse is not true.
Where is the key on super moshi Moshi Monsters?
The key is in the skull's head.
Can super key have null value?
No they can not
Can Super key be null?
why there is no answer yet
Is super set of the super key is the super key.?
A superkey is essentially a super set of a key. Consider a relation R(a,b,c,d) where {a} is the key. Any addition to a such as {a,b},{a,c}, {a,b,c} are considered superkeys. Furthermore, if you add more attributes to a superkey, it will be considered a superkey as well. So yes, a superset of a superkey is another superkey.
