Transaction conditions

NRedisStack also supports a more extensive set of conditions that you can add to transactions. They are implemented internally using WATCH commands in a way that is guaranteed to be safe, without interactions between different clients. Although conditions don't provide exactly the same behavior as explicit WATCH commands, they are convenient to use and execute efficiently.

The example below shows how to use the AddCondition() method on a transaction to let it run only if a specified hash key does not already exist. See Pipelines and transactions for more information about transactions.

var watchedTrans = new Transaction(db);

watchedTrans.AddCondition(Condition.KeyNotExists("customer:39182"));

watchedTrans.Db.HashSetAsync(
    "customer:39182",
    new HashEntry[]{
        new HashEntry("name", "David"),
        new HashEntry("age", "27")
    }
);

bool succeeded = watchedTrans.Execute();
Console.WriteLine(succeeded); // >>> true

The table below describes the full set of conditions you can add to a transaction. Note that you can add more than one condition to the same transaction if necessary.