Database - The Relational Model and Normalization - Discussion
Discussion Forum : The Relational Model and Normalization - General Questions (Q.No. 14)
14.
A key:
Discussion:
16 comments Page 1 of 2.
Tripti said:
5 years ago
Key extract data from a table, it is a set of attributes which can uniquely identify a row or a tuple from a table.
Tripti said:
5 years ago
A DBMS key is an attribute or set of an attribute which helps you to identify a row (tuple) in a relation(table). They allow you to find the relation between two tables. Keys help you uniquely identify a row in a table by a combination of one or more columns in that table.
Garg said:
9 years ago
From key we get result as row not as coloum hence, key defines a row. Please refer definition of key.
Krishna said:
10 years ago
A key is definitely a constraint which is applied on the column which helps column to have a unique value, but each value in a column is row. Hence key identifies a row.
Hudson exaud said:
1 decade ago
Correct answer is D.
A key is the one that uniquely identify a column in relation.
A key is the one that uniquely identify a column in relation.
(1)
Roja iza said:
1 decade ago
A key column is one that uniquely identifies a particular row in the table.
Chandra bahadur tamang said:
1 decade ago
However Key is related to column and applied to it, but it represents whole records.
Jem said:
1 decade ago
Suppose take primary key, composite key. So it is applied on column so it is identified column not row.
(1)
Sambit kumar rout said:
1 decade ago
The definition of key says: key is a single valued attribute or a combination of attributes which is used to identify one or more "RECORD" from the table.
As the definition says that it identifies record(s) and in database record refers to a tuple or row. So key identifies a row.
As the definition says that it identifies record(s) and in database record refers to a tuple or row. So key identifies a row.
Naveen said:
1 decade ago
How a key uniquely define a row ?
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