Berkeley DB: Storing List of values for a Key

Question

Consider a sample application where we need to store Customer name as primary key and list of his transactions as value in Berkeley db. Do berkeley support storing list of values against a primary key? If so, how to approach designing the entity?

Answer 1

The most common approach would be to save the records as a data storage type, such as XML (or JSON, if you prefer that sort of thing). Here's an example in C# that I came up with that stores the records as JSON objects in the database:

        static void Main(string[] args)
    {
        var db = BTreeDatabase.Open("customers.db", new BTreeDatabaseConfig {Creation = CreatePolicy.ALWAYS});

        for (int i = 0; i < 10000; i++)
        {
            var customer = new Customer
            {
                customerName = nameGenerator.GenerateRandomFirstAndLastName()
            };
            var list = new List<Transaction>();
            for (int j = 0; j < 10; j++)
            {
                list.Add(new Transaction
                    {txAmount = random.NextDouble(), txDate = DateTime.Now, txId = randomString()});
            }

            customer.transactions = list;
            db.Put(new DatabaseEntry(Encoding.Default.GetBytes(customer.customerName)),
                new DatabaseEntry(Encoding.Default.GetBytes(JsonConvert.SerializeObject(customer))));
        }

        WriteLine("Completed!");
        ReadLine();
    }

Granted, this isn't the most efficient way, since I store the customer name twice, but it should be a good starting point.