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Column combination for a given column of a join view table 

To determine the combination of columns for a given column v in the join view table V, use the following procedure:

  1. Determine the base table Tj containing the column which corresponds to v.
  2. Determine the unique table sequence Til...Tik that contains Tj.
  3. Determine the last table Til in this sequence that has a 1:1 relationship with the key table.
  4. The columns of V, which correspond to the foreign key columns of Til of the referential CONSTRAINT definition between Til and Til+I that is relevant for V, are elements of the column combination.
  5. All columns of V which correspond to columns of the tables Til+l...Tik are elements of the column combination.

To update the column value of the column v in an UPDATE statement, a value must be specified for each of the columns of the column combination.

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