To understand the role of the Extraction utility (dbxtract) and the Extract Database Wizard in multi-tiered arrangements, consider a three-tiered SQL Remote system. This system is illustrated in the following diagram.

To create the remote databases for a three-tiered system

1. Use the Extraction utility (dbxtract) on the top-level, consolidated database, HQ, to create the second-level databases Region 1 and Region 2.

2. Use the Extraction utility (dbxtract), on the second-level databases, Region 1 and Region 2, to create the third-level databases for users Laptop 1, Laptop 2, and Laptop 3. The second-level databases are remote databases to the first-level database, HQ, and are consolidated databases to the third-level databases, Laptop 1, Laptop 2, and Laptop 3.

Re-extracting databases in a multi-tier hierarchy system

If you have to re-extract the schema for the second-level database from the top-level consolidated database, the Extraction utility (dbxtract) deletes the remote users (Laptop 1, Laptop 2, and Laptop 3) along with their subscriptions and permissions. As a result, you must recreate those third-level users and their subscriptions manually.

If you only have to re-extract the data from the second-level databases from the top-level consolidated database, the Extraction utility (dbxtract) does not affect the remote users. See the -d option Extraction utility (dbxtract).

Fully qualified publication definitions

Fully qualified publication definitions contain WHERE and SUBSCRIBE BY clauses. In most cases, you do not need to extract fully qualified publication definitions for a remote database, since the remote database typically replicates all rows back to the consolidated database.

See also

• Creating multiple remote databases
• Extracting remote databases to a reload file