Updating Multiple Databases


The Java EE transaction manager controls all enterprise bean transactions except for bean-managed JDBC transactions. The Java EE transaction manager allows an enterprise bean to update multiple databases within a transaction. The figures that follow show two scenarios for updating multiple databases in a single transaction.

In Figure 332, the client invokes a business method in Bean-A. The business method begins a transaction, updates Database X, updates Database Y, and invokes a business method in Bean-B. The second business method updates Database Z and returns control to the business method in Bean-A, which commits the transaction. All three database updates occur in the same transaction.

Figure 332. Updating Multiple Databases


In Figure 333, the client calls a business method in Bean-A, which begins a transaction and updates Database X. Then Bean-A invokes a method in Bean-B, which resides in a remote Java EE server. The method in Bean-B updates Database Y. The transaction managers of the Java EE servers ensure that both databases are updated in the same transaction.

Figure 333. Updating Multiple Databases across Java EE Servers




The JavaT EE 5 Tutorial
The JavaT EE 5 Tutorial
ISBN: N/A
EAN: N/A
Year: 2004
Pages: 309

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