# 2784 Using Optimistic Locking Can Cause Row Lock Errors When Updating More than One Row

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This issue was introduced in build5. We rolled back to build 4 and no such problem.

1.Optimistic locking is used.
2.There is a TEDBTable object linked to a lookup table in the database that is opened.
3.There is a TClientDataSet object linked to a query which contains a JOIN to the same lookup table.
4.The ClientDataSet values are Posted twice or more.
5.ApplyUpdates is called.

Error EDB_ERROR_CONSTRAINT or EDB_ERROR_LOCKROW occurs on the row that the TEDBTable is currently on.