Sybase DC38133-01-0902-01 manual Understanding this helps in designing efficient publications

♦ The subscription expression in this example returns a single value. Subqueries returning multiple values can also be used. The value of the subscription expression must the value after the UPDATE.

In this case, the only subscriber to the row is the new sales representative. In “Sharing rows among several subscriptions” on page 112 , we see cases where there are existing as well as new subscribers.

Information in the	Here we describe the information placed in the transaction log.
transaction log	Understanding this helps in designing efficient publications.
	♦ Assume the following data:

∙ SalesRep table

rep_key Name

rep1		Ann
rep2		Marc
∙ Customer table
cust_key	name		rep_key
cust1	Sybase		rep1
cust2	ASA		rep2
∙ Contact table
contact_key	name		cust_key
contact1	David		cust1
contact2	Stefanie		cust2

♦Now apply the following territory realignment Update statement

UPDATE Customer

SET rep_key = ’rep2’

WHERE cust_key = ’cust1’

The transaction log would contain two entries arising from this statement: one for the BEFORE trigger on the Contact table, and one for the actual UPDATE to the Customer table.

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