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1. Top results related to what is a super key?

   • What is a super-recursive algorithm?

     Top Answer

     Answered Sep 19, 2014 · 17 votes

     Recursive here does not refer to an algorithm that uses itself as a subroutine; rather, it refers to the class of recursive functions, which are those which can be computed by a Turing machine. A super-recursive function, then, would be a function which a Turing machine is not powerful enough to compute, requiring a more powerful computing model.

     For example, the halting problem would require a super-recursive algorithm, since it is not solvable using an ordinary Turing machine.

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   • What is the difference between primary key, candidate key and super key in terms of functional dependency

     Top Answer

     Answered Oct 23, 2017 · 0 votes

     Given a relation R with a set of attributes T and a set of functional depedencies F, any set of attributes K, subset of T, that determines T is called a superkey of R. In other words, if the dependency K -> T belongs to F+ (that is, can be derived from F), then K is a superkey of R. From this definition, since it is always true that T -> T, we know at least a superkey exists (T).

     A candidate key CK is a superkey from which we cannot remove any attribute without causing it to lose the property of being a superkey. In other words, if CK = A1,...,An, then there is no proper subset of it which is a superkey. Of course from this definition we can infer that each superkey with a single attribute is automatically a candidate key.

     A primary key has nothing to do with the relation theory, but it is a concept used in practice, inside relational database management systems. In general, it is either a candidate key chosen among those availables, or it is an "artificial" unique identifier (surrogate key) introduced without any consideration of candidate keys already present in the relation.

     Finally note that null values are not defined in the relational theory, but only in practical relational database management systems, and usually in those systems the primary keys cannot have a null value.

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   • What is a key hash?Why it is needed?Is it unique?Why it is necessary for facebook integration

     Top Answer

     Answered Jun 20, 2020 · 2 votes

     What is key Hash?

     It's a 28 character string that Facebook uses to authenticate interactions between your app and the Facebook.

     Why it is Unique?

     As already mentioned in comments, It identifies your app in Facebook developer platform.

     Why it is needed? Why it is necessary for Facebook Integration?

     It is needed to authenticate the exchange of information between your app and the Facebook. Without this, your Facebook integration may not work properly when you release your app to the store. If you run apps that use Facebook Login then you need to add your Android development key hash to your Facebook developer profile.

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     3/5

   • What is a Key Lookup in a Database and what's the difference with Business Rules?

     Top Answer

     Answered Sep 30, 2010 · 2 votes

     A key lookup is an operator used in a query plan and as a general rule points to a lack of a covering index

     http://technet.microsoft.com/en-us/library/bb326635.aspx

     I’m not sure about what context you are using business rules in, maybe some kind of check constraint?

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     what is a super key in database	what is a super key and candidate key
     what is a super key on a keyboard	what is a super key in sql

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   What is a Super key in a relation?

   • Super Key: Super Key is an attribute (or set of attributes) that is used to uniquely identifies all attributes in a relation. All super keys can’t be candidate keys but the reverse is true. In relation, a number of super keys is more than a number of candidate keys.

   Difference between Super Key and Candidate Key - GeeksforGeeks

   www.geeksforgeeks.org/difference-between-super-key-and-candidate-key/

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   What is a Super key?

   • We can define a super key as a set of those keys that identify a row or a tuple uniquely. The word super denotes the superiority of a key. Thus, a super key is the superset of a key known as a Candidate key (discussed in the next section). It means a candidate key is obtained from a super key only.

   Super Key in DBMS - javatpoint

   www.javatpoint.com/super-key-in-dbms

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   What is Super key in DBMS?

   • Definition of Super Key in DBMS: A super key is a set of one or more attributes (columns), which can uniquely identify a row in a table. Often DBMS beginners get confused between super key and candidate key, so we will also discuss candidate key and its relation with super key in this article. How candidate key is different from super key?

   Super key in DBMS - BeginnersBook

   beginnersbook.com/2015/04/super-key-in-dbms/

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   What is the difference between Super key and candidate key?

   • Difference between Super Key and Candidate Key: Super Key is an attribute (or set of attributes) that is used to uniquely identifies all attributes in a relation. Candidate Key is a subset of a super key. All super keys can’t be candidate keys. But all candidate keys are super keys.

   Difference between Super Key and Candidate Key - GeeksforGeeks

   www.geeksforgeeks.org/difference-between-super-key-and-candidate-key/

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3. www.geeksforgeeks.org › difference-between-superDifference between Super Key and Candidate Key - GeeksforGeeks

   www.geeksforgeeks.org › difference-between-super

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   Jul 12, 2022 · Super Key: Super Key is an attribute (or set of attributes) that is used to uniquely identifies all attributes in a relation. All super keys can’t be candidate keys but its reverse is true. In a relation, number of super keys are more than number of candidate keys.

4. stackoverflow.com › questions › 4519825What are the differences between a superkey and a candidate key?

   stackoverflow.com › questions › 4519825

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   Super Key: A superkey is any set of attributes for which the values are guaranteed to be unique for all possible set of tuples in a table at all time. Candidate Key: A candidate key is a 'minimal' super key meaning the smallest subset of superkey attribute which is unique.

   Code sample

   atomic_number INTEGER NOT NULL PRIMARY KEY

     CHECK (atomic_number > 0 AND atomic_number < 120),

   symbol CHAR(3) NOT NULL UNIQUE,

   name CHAR(20) NOT NULL UNIQUE,

   atomic_weight DECIMAL(8,4) NOT NULL,...

   See more on stackoverflow

5. Videos

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     Lec-13: Super key in DBMS in HINDI | ये Question Competition Exams में अक्सर पूछा गया है

     Jan 6, 2019

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     Super Key in DBMS | How to find it?

     Jan 12, 2022

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     2:08

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     DIFFERENCE BETWEEN SUPER KEY AND CANDIDATE KEY IN DBMS

     Feb 28, 2020

     65.7K Views

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6. www.geeksforgeeks.org › types-of-keys-inTypes of Keys in Relational Model (Candidate, Super, Primary ...

   www.geeksforgeeks.org › types-of-keys-in

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   • Candidate Key
   • Primary Key
   • Super Key
   • Alternate Key
   • Foreign Key
   • Composite Key

   The minimal set of attributes that can uniquely identify a tuple is known as a candidate key. For Example, STUD_NO in STUDENT relation. 1. It is a minimal super key. 2. It is a super key with no repeated data is called a candidate key. 3. The minimal set of attributes that can uniquely identify a record. 4. It must contain unique values. 5. It can ...

   See full list on geeksforgeeks.org

   There can be more than one candidate key in relation out of which one can be chosen as the primary key. For Example, STUD_NO, as well as STUD_PHONE, are candidate keys for relation STUDENT but STUD_NO can be chosen as the primary key(only one out of many candidate keys). 1. It is a unique key. 2. It can identify only one tuple (a record) at a time....

   See full list on geeksforgeeks.org

   The set of attributes that can uniquely identify a tuple is known as Super Key. For Example, STUD_NO, (STUD_NO, STUD_NAME), etc. A super key is a group of single or multiple keys that identifies rows in a table. It supports NULL values. 1. Adding zero or more attributes to the candidate key generates the super key. 2. A candidate key is a super key...

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   The candidate key other than the primary key is called an alternate key. 1. All the keys which are not primary keys are called alternate keys. 2. It is a secondary key. 3. It contains two or more fields to identify two or more records. 4. These values are repeated. 5. Eg:- SNAME, and ADDRESS is Alternate keys Example:

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   If an attribute can only take the values which are present as values of some other attribute, it will be a foreign key to the attribute to which it refers. The relation which is being referenced is called referenced relation and the corresponding attribute is called referenced attribute. The referenced attribute of the referenced relation should be...

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   Sometimes, a table might not have a single column/attribute that uniquely identifies all the records of a table. To uniquely identify rows of a table, a combination of two or more columns/attributes can be used. It still can give duplicate values in rare cases. So, we need to find the optimal set of attributes that can uniquely identify rows in a t...

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7. beginnersbook.com › 2015 › 04Super key in DBMS - BeginnersBook

   beginnersbook.com › 2015 › 04

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   Dec 11, 2018 · Definition of Super Key in DBMS: A super key is a set of one or more attributes (columns), which can uniquely identify a row in a table. Often DBMS beginners get confused between super key and candidate key, so we will also discuss candidate key and its relation with super key in this article.

8. www.javatpoint.com › super-key-in-dbmsSuper Key in DBMS - javatpoint

   www.javatpoint.com › super-key-in-dbms

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   Super Key in DBMS. We can define a super key as a set of those keys that identify a row or a tuple uniquely. The word super denotes the superiority of a key. Thus, a super key is the superset of a key known as a Candidate key (discussed in the next section).

9. en.wikipedia.org › wiki › SuperkeySuperkey - Wikipedia

   en.wikipedia.org › wiki › Superkey

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   In the relational data model a superkey is any set of attributes that uniquely identifies each tuple of a relation. [1] [2] Because superkey values are unique, tuples with the same superkey value must also have the same non-key attribute values.

10. www.simplilearn.com › super-key-in-dbms-articlePower of Super Keys in DBMS: A Beginner's Guide - Simplilearn

    www.simplilearn.com › super-key-in-dbms-article

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    Mar 26, 2024 · Super keys are collections of one or more properties (columns) in database management systems that allow a tuple (row) in a relation (table) to be distinctly identified. Unlike candidate or primary keys, super keys have a wider definition.