Sybase Error 2601 Attempt to insert duplicate key row in object with unique

Question

RE: Sybase Error 2601 Attempt to insert duplicate key row in object with unique index.
Hi Folks,
I'm getting the following error whilst executing a stored procedure in Sybase.
ERROR: Sybase Error 2601 Attempt to insert duplicate key row in object with unique index.
I understand that duplicate values have been inserted into a column that has a unique constraint.
I just can't figure out how to rectify the problem.
Your help will be greatly appreciated!
Many thanks in advance.

Answer 1

If the value I'm trying to insert (using update)
already exists in the unique-value field then the DB
refuses to update the field.
If the value is different it will update.Are you trying to insert or update in SQL (identified by the keyword INSERT or UPDATE respectively)?
Even in case of an UPDATE query, if you are going to update the values of some columns to violate the unique constraints, the update will not succeed and you will get the error message.
or is it?
it tries to create a new row, but can't because there
is another row with the same unique-values.
If this is the case, I am only trying to update and
not create a new item.To put it in simpler words, if you have a set of values defining the uniqueness of a record, you cannot insert another record with the same set of unique values. Similarly, you cannot update an existing record by modifying the set to conflict with another set of unique values which already exist in the database.
Suppose there are two columns A and B defining the uniqueness of the record and you have only two records at the moment like -
A B
========
1 1
2 1
If you try to insert a record with A = 1 and B = 1, it will fail because a record already exists. You cannot violate uniqueness because the database has already been told that there will be only one record for any given combination of A and B.
Similarly, if you try to update the second record from A = 2 to A = 1, the end result would be A =1 and B = 1. There is already a record with that set of values and this will result in a violation of the uniqueness. So, this update will also be disallowed. On the other hand, if you try to update B to some value, say 3, there is no problem in doing so.
For convenience, you can imagine an UPDATE operation to be equivalent to DELETE + INSERT operation, though it doesn't necessarily work the same way internally.
I hope I was clear enough.