Question

I’m new to RaveDB (Actually I’ve started learn it only yesterday). And try to implement some functionality.

Lets we have next class hierarchy:

public abstract class Transaction
{
    public string Id { get; set; }
}

public class CategoryTransaction : Transaction
{
    public string AccountId { get; set; }

    public string Name { get; set; }

    public string Category { get; set; }

    public decimal Amount { get; set; }
}

public class ExchangeTransaction : Transaction
{
    public string DebitAccountId { get; set; }

    public string CreditAccountId { get; set; }

    public decimal DebitAmount { get; set; }

    public decimal CreditAmount { get; set; }
}

Everything storing excelent int db. I event add Conventions = FindTypeTagName ... for store documents as ‘transactions/*’ document id.

But I want to create index for select all transactions for specific Account (by field AccountId). I’ve create index:

public class AccountTransactionResult
{
    public string AccId { get; set; }
}

public class Account_Transactions : AbstractMultiMapIndexCreationTask<AccountTransactionResult>
{
    public Account_Transactions()
    {
        this.AddMap<CategoryTransaction>( transactions => from transaction in transactions
                                                            select new
                                                                    {
                                                                    AccId = transaction.AccountId
                                                                    } );
        this.AddMap<ExchangeTransaction>( transactions => from transaction in transactions
                                                            select new
                                                                    {
                                                                    AccId = transaction.DebitAccountId
                                                                    } );
        this.AddMap<ExchangeTransaction>( transactions => from transaction in transactions
                                                            select new
                                                                    {
                                                                    AccId = transaction.CreditAccountId
                                                                    } );
    }
}

This index works well I can’t get all type of transactions from DB (Exchange and Category) as single IEnumerable<Transaction>. That is great.

But I want to use the index to return transactions only for particular account. Because ExchangeTransaction can belong to two Accounts. I want to see ExchangeTransaction for both Accounts. I can make query in Raven Studio by AccId (index field) and it works greate! But I can’t create the same request in the code :(.

Can someone help me? How can I use index field AccId in C# LINQ query?

This code

var query = session.Query<Transaction, Account_Transactions>()

return all type of transaction, but I don’t how to filter the transactions by index field in the DB.

Thanks in advance. And please sorry me my English, it is not my native language.

Answer 1

My fault, in documentation everythings is clear. I missed some useful paragraph.

The easiest way to do this is by writing a multi-map index like this
one:

public class AnimalsIndex : AbstractMultiMapIndexCreationTask
{
    public AnimalsIndex()
    {
        AddMap<Cat>(cats => from c in cats
                            select new { c.Name });

        AddMap<Dog>(dogs => from d in dogs
                            select new { d.Name });
    }
}

And query it like this:

var results = session.Advanced.LuceneQuery<object>("AnimalsIndex")
    .WhereEquals("Name", "Mitzy");

>

In my case I should use next construction:

var transactions = session.Advanced.LuceneQuery<Transaction>( "Account/Transactions" )
                    .WhereEquals( "AccId", account2.Id )

And everything is working now.