primary key
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If a primary key is dropped from a table and some records are duplicated after dropping primary key, then is it possible to apply the primary key on the same column. If yes, then how??
NEHA GUPTA
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If a primary key is dropped from a table and some records are duplicated after dropping primary key, then is it possible to apply the primary key on the same column. If yes, then how??
NEHA GUPTA
No, not really. The whole point of a primary key is that it is unique for each row (be it a surrogate key or a key made up from several columns). If you have duplicate rows then, by definition, you will be breaking the rule. Remove the duplicate rows and then apply a primary key. Why would you deliberately remove the primary key and add duplicate rows?
"If you think it's expensive to hire a professional to do the job, wait until you hire an amateur." Red Adair. nils illegitimus carborundum me, me, me
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If a primary key is dropped from a table and some records are duplicated after dropping primary key, then is it possible to apply the primary key on the same column. If yes, then how??
NEHA GUPTA
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ya how can again you set the primary key which already have two rows of same key ??? it is not possible...
suchita
but there is some option when we alter the table, (when we add constraint) with an option "with check" and "with nocheck". What is that option? Please clarify..
NEHA GUPTA
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but there is some option when we alter the table, (when we add constraint) with an option "with check" and "with nocheck". What is that option? Please clarify..
NEHA GUPTA
If you add a new constraint, Sql Server will test whether or not all of the records that are currently in the table pass that constraint. Adding the
NOCHECKoption will skip that test. You'd have to remove any double entries to recreate your primary key.I are Troll :suss: