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.
Nishith said:
1 decade ago
How a row?
A key is a constraint which is applied on a column.
A key is a constraint which is applied on a column.
Pratibha said:
1 decade ago
option:D is correct.
Harshal said:
1 decade ago
Redcords are of particular table are stored as in rows and if we have a key then it ifentifies a that particular row in which entered key belongs.
Charu said:
1 decade ago
Key is a constraint which is applied on a column not on the row.
Kamlesh said:
1 decade ago
Def on Key: A key is one or more data attributes that uniquely identify an entity. In a physical database a key would be formed of one or more table columns whose value(s) uniquely identifies a row within a relational table.
Divye said:
1 decade ago
A key can be constraint on a row as its defination states so.
Naveen said:
1 decade ago
How a key uniquely define a row ?
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.
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)
Chandra bahadur tamang said:
1 decade ago
However Key is related to column and applied to it, but it represents whole records.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers