Sybase DC38133-01-0902-01 manual Statement, Representatives, Clause of the Update statement

Chapter 6. Principles of SQL Remote Design

UPDATE statement may differ from the entered UPDATE statement.

UPDATE statements If an UPDATE statement has the effect of removing a row from a given replicated as INSERTS remote user’s subscription, it is sent to that user as a DELETE statement. If

or DELETESan UPDATE statement has the effect of adding a row to a given remote user’s subscription, it is sent to that user as an INSERT statement.

The figure illustrates a publication, where each subscriber subscribes by their name:

ConsolidatedAnn

	ID	Rep		Dept		ID	Rep
	1	Ann		101		1	Ann
	2	Marc		101
	3	Marc		101
	Consolidated					Ann
	ID	Rep		Dept		ID	Rep
1		Ann		101		1	Ann
					>
2		Marc		101		3	Ann
3		Ann	101

Marc

ID	Rep
2	Marc
3	Marc

Marc

ID Rep

2 Marc

3 Marc

	An UPDATE that changes the Rep value of a row from Marc to Ann is
	replicated to Marc as a DELETE statement, and to Ann as an INSERT
	statement.
	This reassignment of rows among subscribers is sometimes called territory
	realignment, because it is a common feature of sales force automation
	applications, where customers are periodically reassigned among
	representatives.
UPDATE conflict	An UPDATE statement changes the value of one or more rows from some
detection	existing value to a new value. The rows altered depend on the WHERE
	clause of the UPDATE statement.
	When SQL Remote replicates an UPDATE statement, it does so as a set of
	single-row updates. These single-row statements can fail for one of the
	following reasons:
	♦ The row to be updated does not exist Each row is identified by its
	primary key values, and if a primary key has been altered by some other
	user, the row to be updated is not found.

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