| composite primary keys [message #372047] |
Fri, 05 January 2001 16:13  |
dan kim
Messages: 3
Registered: January 2001
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Junior Member |
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got a question. i have a single column primary key trying to reference a table that has a 2 column composite primary key. when i use the reference command when creating the table, i get the error:
ORA-02256 number of referencing columns must match referenced columns
Cause: The number of columns in the foreign-key referencing list is not equal to the number of columns in the referenced list.
Action: Make sure that the referencing columns match the referenced columns.
does this mean that a parent key must be composite to reference a child composite key? is there a way to reference my single column primary key parent table to a child composite key table?
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| Re: composite primary keys - wrong way around? [message #372063 is a reply to message #372047] |
Mon, 08 January 2001 14:31  |
Andrew again...
Messages: 270
Registered: July 2000
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Senior Member |
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It sounds like you could have the references command the wrong way around? Remember that the references command applies to the Child table, specifying what the Parent table is. Your 2 column composite table must be the child table, as it's PK can have the value from the single col PK column repeated.
e.g.
Order
1
2
3
Order_Item
1, a
1, b
2, a
Order_Item table references Order table. Do try to resolve this referential integrity, it is important.
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