Adding an isolation level

You can use the deployment descriptor editor to add an isolation level to a CMP entity bean 1.x.

To add an isolation level to an a CMP entity bean 1.x with container-managed persistence:

  1. Switch to the J2EE perspective.
  2. In the Project Explorer view, select the desired EJB module.
  3. Right-click on the Deployment Descriptor Editor and select Open With from the pop-up menu.
  4. On the Access page of the editor, scroll to the Isolation level section.
  5. Click Add. The Add Isolation Level wizard appears.
  6. Select a type of isolation level from the following choices:
    • Repeatable read: This isolation level prohibits dirty reads and nonrepeatable reads, but it allows phantom reads.
    • Read committed: This isolation level prohibits dirty reads, but allows nonrepeatable reads and phantom reads.
    • Read uncommitted: This isolation level allows reading uncommitted changes (data changed by a different transaction that is still in progress). It also allows dirty reads, nonrepeatable reads, and phantom reads.
    • Serializable: This isolation level prohibits the following types of reads: 1) Dirty reads, in which a transaction reads a database row containing uncommitted changes from a second transaction, 2) Nonrepeatable reads, in which one transaction reads a row, a second transaction changes the same row, and the first transaction rereads the row and gets a different value, and 3) Phantom reads, in which one transaction reads all rows that satisfy an SQL WHERE condition, a second transaction inserts a row that also satisfies the WHERE condition, and the first transaction applies the same WHERE condition and gets the row inserted by the second transaction.
  7. Click Next.
  8. Select one or more enterprise beans from the list of beans found, then click Next. The enterprise beans selected here are the ones whose methods you want to assign to the isolation level.
  9. Select one or more of the method elements from the list.
  10. Click Finish.
The isolation level is added. To remove the isolation level, select it and click the Remove button.

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