Update an Item attribute

Users Dgraph
1

Is there an update item option with the dgraph-js. I do not see it in the documentation

Is the only way to delete the item then create a new item with the new data.

I am using DQL by the way and an example of the type I am using is

type Comment {
	Comment.commentId
	Comment.username
	Comment.likes
	Comment.comment
  Comment.likesCount
}

I would like to increment / decrement Comment.likesCount because I need to orderdesc

2

The answer is this

async function IncrementOrDecrementHashtagPins(
    hashtag: string,
    increment: boolean
): Promise<boolean> {
    // Hashtag.pinnedByCount: int .
    const txn = dgraphClient.newTxn({});
    try {
        const uid = await GetHashtagUid(hashtag);
        if (!uid) return false;
        const mutation = new dgraph.Mutation();
        if (increment) {
            mutation.setSetNquads(
                `<${uid}> <Hashtag.pinnedByCount> "1"^^<xs:int> .`
            );
        } else {
            mutation.setSetNquads(
                `<${uid}> <Hashtag.pinnedByCount> "-1"^^<xs:int> .`
            );
        }
        await txn.mutate(mutation);
        await txn.commit();
        return true;
    } catch (err) {
        return false;
    } finally {
        await txn.discard();
    }
}
3

Try to use Upsert Block. You can use math to do sum or subtraction. In one Upsert you can do math(Var1+1) and in the other you can do something like “math(var1-1)”.

4

is one better than the other in terms of speed or error handling?

5

There’s no error handling in DQL.
Upserts are better cuz it checks for the value on the fly and does the upsert. It guarantees unicity.