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  • Category: SQL Server

    WIll Primary key allow null?

    I created a table through Query where I set a particular column as PrimaryKey..It does not accept duplicate values when i try to insert them..However it accepts null..Will Primary key accept null values?
  • #282940
    never allows null

  • #282941
    Primary key will not allow the null values. If you want to allow null values you have to go for foriegn key.

    All is well.
    Try and fail but don't fail and try

  • #282943
    hi suresh here...
    if u ve created primary key for a column it will not allow null values...if u tried to click allow nulls property in enterprise manager it shows the following error(allow nulls property can not beset on a column which is the part of the primary key)

  • #282944
    Then how did it allow null values?

  • #282985
    Primary key will not allow the null values
    you are saying,ur created table with primary key allows null values na
    please send ur crated table script

  • #283108
    Hi Cathrin ,
    look, a primary key means unique and not null. it means it would not allow either null value or not unique value. on the other hand a composite (but bot primary) or foreign key will accept a null or unique value. hope this informaion will help you.

  • #283119
    The main advantage of the primary key is not allowing the null values into columns.It would be better if you provide more details like table format.So that we can give our look on that.

  • #283591

    Primary key and unique key does not allow enter duplicate data.
    Primary key and unique are Entity integrity constraints.unique key can be null but primariy key cant be null.
    primariy key can be refrenced to other table as FK.We can declare only one primary key in a table but a table can have multiple unique key(column assign

    i hope this may help u

    Thanks & Regards
    Nothing is mine ,Everything is yours!!!

  • #284378
    Primary key wont allow null values and duplicate values

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