Struggling with Transactions

[renatospaka]

Hi, I am reading the Neo4j Go Driver Manual v4.2 and there is a session with a non-functional piece of code on page #23

I want to create an ACID transaction similar to the code above. Then I'm looking for a gist or Github repository or an example of how to use transactions (BeginTransaction, a few WriteTransaction's, commit or rollback statements depending on the case) so I can take a look at. The samples found in Neo4j documentation show only auto-commit transactions.

I'm really struggling with these statements:

//To attach a metadata to an explicit transaction:
session.BeginTransaction(WithTxMetadata(map[string)interface{}{"work-id": 1}))  <====

// To attach a metadata to a write transaction function:
session.WriteTransaction(DoWork, WithTxMetadata(map[string)interface{}{"work-id": 1}))
session.WriteTransaction(DoWork2, WithTxMetadata(map[string)interface{}{"work-id": 104}))

I don't get why is necessary to set WithTxMetadata to begin a transaction.

Completely lost here...

[florent_biville]

Hi, the recommended approach is to use session.ReadTransaction or session.WriteTransaction.
Do you need transaction metadata at all?

If not, you can run statements like this one.

[renatospaka]

Hi Florent.

I checked this code out. But it handles one transaction at time.

What I want to do is handle multiple Write transactions in a single ACID transaction - all successful or all fail. I guess I should use BeginTransaction to do this but not sure, it is not clear if this is the proper approach. Is this the approach of the Golang Neo4j community?

[florent_biville · Accepted solution]

You can do something like this:

	transaction, err := session.BeginTransaction()
	if err != nil {
		panic(err)
	}
	defer transaction.Close()
	params := map[string]interface{}{"prop": "some property"}
	if _, err := transaction.Run("CREATE (n:SomeNode {with: $prop})", params); err != nil {
		err = transaction.Rollback()
        // handle rollback error, if any
	}
	if _, err = transaction.Run("MATCH (n:SomeNode {with: $prop}) SET n:AnotherLabel", params); err != nil {
		err = transaction.Rollback()
        // handle rollback error, if any
	}
	transaction.Commit()

Does that help?
If so, what is this page 23 of the driver manual that needs fixing you referred to in your initial question?

[renatospaka]

Florent, the example will do. Thank you very much.

Regarding the manual, I have downloaded Neo4j Go Driver Manual v4.2 (PDF) from Neo4j Documentation website. At page #25 there is that piece of code that doesn't work.

[florent_biville]

I just looked at https://neo4j.com/docs/pdf/neo4j-driver-manual-4.2-go.pdf and I could not find any code at page 25. Is this on another page perhaps?

[renatospaka]

I'm very sorry for the delay.

Here, I took a screenshot of the page and made some marks on it.

This time I opened the PDF directly in the browser from Neo4j's documentation page.

Hope this helps (in case the code in this page is really wrong)
Best regards

[florent_biville]

Thanks, the code is indeed incorrect in this section. Thanks for the report!