CODEWITHSUNDEEP
google-app-enginetransactions
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Reputation: 153

Google App Engine transactional inserts in Java

I have tried to insert/update multiple entites on a single transaction but no avail. It always throws IllegalArgumentException.

I wanted to do something like this.

Transaction tx = pm.currentTransaction();
tx.begin();

for(int i=0;i<10;i++) {
    SampleEntity entity = new SampleEntity(i);
    pm.makePersistent(entity);
}

tx.commit();

If this is not possible, is there a workaround to make it work? Thanks.

Upvotes: 0

Views: 689

Answers (1)

Jason Hall
Jason Hall

Reputation: 20920

The docs on Transactions should be helpful here, especially the section on Entity Groups.

Entity groups tell App Engine to store multiple entities in the same node of the datastore -- otherwise, a transaction would require tons of cross-node communication and be nearly impossible to get right.

Entity groups are primarily used for parent-child relationships, so that a child entity can be updated in the same transaction as is parent.

Upvotes: 1

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