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swafophile
Starting Member
3 Posts |
 Posted - 2010-04-12 : 16:12:35
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| I have the following constraint creating a primary key referencing three integers in the table that will identify the row as unique only when all three are put together....but this statement doesn't actually create a column for the primary key. Although it runs and says the table was created successfully there is no primary key column. In short, what is the purpose of creating a primary key constraint like this and what can you use it for?CONSTRAINT Ing_Id PRIMARY KEY (Class_Id, SubClass_Id, Spec_Id)If instead I wanted to create another column that strung the three integers together (i.e. 1+2+3=123) and use that as the primary key would that be easier?thanks everyone for any help you can provide |
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dinakar
Master Smack Fu Yak Hacker
2507 Posts |
Posted - 2010-04-12 : 16:31:01
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| Correct. Primary Key is a constraint that you enforce on a (set) of columns.. run a select on sys.sysconstraints and join it back to the sys.tables by ID and you can see your constraint. You can also use sp_help 'table' to get all the table information - columns, constraints etc.Dinakar Nethi************************Life is short. Enjoy it.************************http://weblogs.sqlteam.com/dinakar/ |
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swafophile
Starting Member
3 Posts |
Posted - 2010-04-12 : 16:39:39
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| so i can't reference this primary key (i.e. table_name(Ing_ID)) in other tables? that is what i'm having trouble figuring out...it's just a constraint, not a usable value?thanks |
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swafophile
Starting Member
3 Posts |
Posted - 2010-04-12 : 16:41:34
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| okay i think i understand that then....so if i wanted to string the three integers together to create a primary key int how could i do that??thanks again |
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primary key constraints