User's Manual

Chapter 11. Administering SQL Remote for Adaptive Server
Anywhere
messages, in the order in which the statements are recorded in the log.
Passthrough is commonly used to send data definition language statements.
In this case, replicated DML statements use the before schema before the
passthrough and the after schema following the passthrough.
Notes on using
passthrough mode
♦ You should always test your passthrough operations on a test database
with a remote database subscribed. You should never run untested
passthrough scripts against a production database.
♦ You should always qualify object names with the owner name.
PASSTHROUGH statements are not executed at remote databases from
the same user ID. Consequently, object names without the owner name
qualifier may not be resolved correctly.
Uses and limitations of passthrough mode
Passthrough mode is a powerful tool, and should be used with care. Some
statements, especially data definition statements, could cause a running
SQL Remote setup to come tumbling down. SQL Remote relies on each
database in a setup having the same objects: if a table is altered at some sites
but not at others, attempts to replicate data changes will fail.
Also, it is important to remember that in the default setting passthrough
mode also executes statements at the local database. To send statements to a
remote database without executing them locally you must supply the ONLY
keyword. When a passthrough session contains calls to stored procedures,
the procedures must exist in the server that is issuing the passthrough
commands, even if they are not being executed locally at the server. The
following set of statements drops a table not only at a remote database, but
also at the consolidated database.
-- Drop a table at the remote database
-- and at the local database
PASSTHROUGH TO Joe_Remote ;
DROP TABLE CrucialData ;
PASSTHROUGH STOP ;
The syntax to drop a table at the remote database only is as follows:
-- Drop a table at the remote database only
PASSTHROUGH ONLY TO Joe_Remote ;
DROP TABLE CrucialData ;
PASSTHROUGH STOP ;
The following are tasks that can be carried out on a running SQL Remote
setup:
♦ Add new users.
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