# SqlSaga base class

<!-- Version variant: sqlpersistence_7; default: [/persistence/sql/sqlsaga.md](/persistence/sql/sqlsaga.md) -->


> [!WARNING]
> Starting in version 8.3.0, the `SqlSaga<T>` class is deprecated. With the [simplified message correlation syntax](/nservicebus/sagas/message-correlation.md) that does not repeat the `.ToSaga(…)` mapping, the alternate saga base class is no longer necessary.
>
> When using a standard `Saga<T>` base class, the correlation id is determined by analysis of the `ConfigureHowToFindSaga` method.
>
> A [transitional correlation id](/persistence/sql/saga.md#correlation-ids-transitional-correlation-id) (a feature exlusive to SQL Persistence) can still be applied using the `[SqlSaga]` attribute applied to a saga class.
>
> The generated [table name](/persistence/sql/saga.md#table-structure-table-name) can also be set using the `[SqlSaga]` attribute.

`SqlSaga<T>` is an alternate saga base class for use with SQL persistence that offers a less verbose mapping API than `NServiceBus.Saga<T>`. New projects should use `NServiceBus.Saga<T>` by default.

## SqlSaga definition

A saga can be implemented using the `SqlSaga` base class as follows:

<!-- snippet: SqlPersistenceSaga -->

```cs
public class OrderSaga :
    SqlSaga<OrderSaga.SagaData>,
    IAmStartedByMessages<StartOrder>
{
    static ILog log = LogManager.GetLogger<OrderSaga>();

    protected override void ConfigureMapping(IMessagePropertyMapper mapper)
    {
        mapper.ConfigureMapping<StartOrder>(message => message.OrderId);
    }

    protected override string CorrelationPropertyName => nameof(SagaData.OrderId);

    public Task Handle(StartOrder message, IMessageHandlerContext context)
    {
        log.Info($"Received StartOrder message {Data.OrderId}.");
        MarkAsComplete();
        return Task.CompletedTask;
    }

    public class SagaData :
        ContainSagaData
    {
        public Guid OrderId { get; set; }
    }
}
```

<!-- endsnippet -->

Note that there are differences to how a standard NServiceBus saga is implemented.

## Correlation IDs

Instead of inferring the correlation property from multiple calls to `.ToSaga(sagaData => sagaData.CorrelationPropertyName)`, the `SqlSaga` base class identifies the correlation property once as a class-level property.

### Single correlation ID

In most cases there will be a single correlation ID per Saga Type.

<!-- snippet: SqlPersistenceSagaWithCorrelation -->

```cs
public class SagaWithCorrelation :
    SqlSaga<SagaWithCorrelation.SagaData>,
    IAmStartedByMessages<StartSagaMessage>
{
    protected override void ConfigureMapping(IMessagePropertyMapper mapper)
    {
        mapper.ConfigureMapping<StartSagaMessage>(message => message.CorrelationProperty);
    }

    protected override string CorrelationPropertyName => nameof(SagaData.CorrelationProperty);

    public Task Handle(StartSagaMessage message, IMessageHandlerContext context)
    {
        return Task.CompletedTask;
    }

    public class SagaData :
        ContainSagaData
    {
        public Guid CorrelationProperty { get; set; }
    }
}
```

<!-- endsnippet -->

### Correlation and transitional IDs

During the migration from one correlation ID to another correlation ID, there may be two correlation IDs that co-exist. See also the [Transitioning Correlation IDs sample](/samples/sql-persistence/transitioning-correlation-ids/index.md).

<!-- snippet: SqlPersistenceSagaWithCorrelationAndTransitional -->

```cs
public class SagaWithCorrelationAndTransitional :
    SqlSaga<SagaWithCorrelationAndTransitional.SagaData>,
    IAmStartedByMessages<StartSagaMessage>
{
    protected override void ConfigureMapping(IMessagePropertyMapper mapper)
    {
        mapper.ConfigureMapping<StartSagaMessage>(message => message.CorrelationProperty);
    }

    protected override string CorrelationPropertyName => nameof(SagaData.CorrelationProperty);

    protected override string TransitionalCorrelationPropertyName => nameof(SagaData.TransitionalCorrelationProperty);

    public Task Handle(StartSagaMessage message, IMessageHandlerContext context)
    {
        return Task.CompletedTask;
    }

    public class SagaData :
        ContainSagaData
    {
        public Guid CorrelationProperty { get; set; }
        public Guid TransitionalCorrelationProperty { get; set; }
    }
}
```

<!-- endsnippet -->

### No correlation ID

When implementing a [custom saga finder](/nservicebus/sagas/saga-finding.md) it is possible to have a message that does not map to a correlation ID and instead interrogates the JSON-serialized data stored in the database.

<!-- snippet: SqlPersistenceSagaWithNoMessageMapping -->

```cs
public class SagaWithNoMessageMapping :
    SqlSaga<SagaWithNoMessageMapping.SagaData>
{
    protected override void ConfigureMapping(IMessagePropertyMapper mapper)
    {
    }

    protected override string CorrelationPropertyName => null;

    public class SagaData :
        ContainSagaData
    {
    }
}
```

<!-- endsnippet -->

## Table suffix

A saga's table suffix, which forms part of the [table name](saga.md#table-structure-table-name) in the database, can also be defined more easily using a property override when using the `SqlSaga<T>` base class:

<!-- snippet: tableSuffix -->

```cs
class MySaga:SqlSaga<MySaga.SagaData>
{
    protected override string TableSuffix => "TheCustomTableName";
```

<!-- endsnippet -->