Conflicts do not apply to UPDATE conflicts do not apply to primary key updates. If the column being

primary keys

updated is a primary key, then when the update from User 2 arrives at the

 

consolidated database, no row will be updated.

 

This section describes how you can build conflict resolution into your

 

SQL Remote installation at the consolidated database.

How SQL Remote handles conflicts

When a conflict is

SQL Remote replication messages include UPDATE statements as a set of

detected

single row updates, each including the values prior to updating.

 

An UPDATE conflict is detected by the database server as a failure of the

 

values to match the rows in the database.

 

Conflicts are detected and resolved by the Message Agent, but only at a

 

consolidated database. When an UPDATE conflict is detected in a message

 

from a remote database, the Message Agent causes the database server to

 

take two actions:

 

1. The UPDATE is applied.

 

2. Any conflict resolution procedures are called.

UPDATE statements are applied even if the VERIFY clause values do not match, whether or not there is a resolve update procedure.

The method of conflict resolution is different at an Adaptive Server Anywhere consolidated database. For more information, see “How SQL Remote handles conflicts” on page 121 .

Implementing conflict resolution

This section describes what you need to do to implement custom conflict resolution in SQL Remote.

Required objects

For each table on which you wish to resolve conflicts, you must create three

 

database objects to handle the resolution:

 

An old value table To hold the values that were stored in the table

 

when the conflicting message arrived.

 

A remote value table

To hold the values stored in the table at the

 

remote database when the conflicting update was applied, as determined

 

from the message.

 

 

A stored procedure

To carry out actions to resolve the conflict.

These objects need to exist only in the consolidated database, as that is where conflict resolution occurs. They should not be included in any publications.

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Sybase DC38133-01-0902-01 Consolidated database, no row will be updated, Values to match the rows in the database, 166