wahts is mean by primary key and unique key?

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Question Posted / ravi

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wahts is mean by primary key and unique key?..

Answer / swapna

Primery Key:- A column or set of columns that uniquely
identify all the rows in a table. Primary keys do not allow
null values. No two rows can have the same primary key
value; therefore, a primary key value always uniquely
identifies a single row.

Unique Key:- Unique Keys are used to uniquely identify each
row in an Oracle table. There can be one and only one row
for each unique key value. no value repeate in the other
rows of the same table.

Is This Answer Correct ?

21 Yes

7 No

wahts is mean by primary key and unique key?..

Answer / seshu

HI ALL

PRIMARY KEY :- UNIQUE+NOT NULL

UNIQUE kEY :- UNIQUE +NULL

Is This Answer Correct ?

13 Yes

0 No

wahts is mean by primary key and unique key?..

Answer / m.karthikeyan

hi dear friends....
unique key is also act as a primary key but it accept the
null values that is the difference b/w them...

Is This Answer Correct ?

14 Yes

3 No

wahts is mean by primary key and unique key?..

Answer / anjani kumar jha

always remember

in 1 table there must be only on primary key,but may have
more than on unique key

Is This Answer Correct ?

12 Yes

4 No

wahts is mean by primary key and unique key?..

Answer / bhausaheb.chate

Primary Key:- Primary Key is an attribute or a set of
attributes in a table which uniquely identifies a record
(row) in a table and no two records (rows) in the table can
have the same values for all the columns comprising the
primary key.

Unique Key:- A unique key is a key which stores unique
values (no duplicates) for that particular column.

Difference between Primary Key & Unique Key:-

1. A Unique key can store a null value and primary key
cannot store any null value.

2. A primary key can be references to another table as a
Foreign Key.

Is This Answer Correct ?

7 Yes

2 No

wahts is mean by primary key and unique key?..

Answer / murugan

A Column or set of Columns that uniquely identify all the
rows in a table......

Is This Answer Correct ?

4 Yes

6 No

wahts is mean by primary key and unique key?..

Answer / bhausaheb.chate

A Column or set of Columns that uniquely identify all the
rows in a table .......

Is This Answer Correct ?

3 Yes

6 No

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