Sybase DC38133-01-0902-01 manual Territory realignment with a many-to-many relationship

Chapter 7. SQL Remote Design for Adaptive Server Anywhere

...

TABLE Policy

SUBSCRIBE BY rep_key,

...

The subscription expression ensures that each sales rep receives only those rows of the table for which the value of the rep_key column matches the value provided in the subscription.

The Policy table partitioning is disjoint: there are no rows that are shared with more than one subscriber.

Customer table A subscription expression with a subquery is used to define the partition. The article is defined as follows:

...

TABLE Customer SUBSCRIBE BY ( SELECT rep_key

FROM Policy

WHERE Policy.cust_key =

	Customer.cust_key
	),
	...
	The Customer partitioning is non-disjoint: some rows are shared with
	more than one subscriber.
Multiple-valued	The subquery in the Customer article returns a single column (rep_key) in
subqueries in	its result set, but may return multiple rows, corresponding to all those sales
publications	representatives that deal with the particular customer. When a subscription
	expression has multiple values, the row is replicated to all subscribers whose
	subscription matches any of the values. It is this ability to have
	multiple-valued subscription expressions that allows non-disjoint
	partitionings of a table.
Territory realignment with a many-to-many relationship
	The problem of territory realignment (reassigning rows among subscribers)
	requires special attention, just as in the section “Territory realignment in the
	Contact example” on page 107 .
	You need to write triggers to maintain proper data throughout the installation
	when territory realignment (reassignment of rows among subscribers) is
	allowed.
How customers are	In this example, we require that a customer transfer be achieved by deleting
transferred	and inserting rows in the Policy table.

To cancel a sales relationship between a customer and a sales representative, a row in the Policy table is deleted. In this case, the Policy table change is properly replicated to the sales representative, and the row no longer appears

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