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george.ricketts_175787 avatar image
george.ricketts_175787 asked joao.reis answered

c# driver and decimals with scale > 28

Hi All,

I'm getting the following issue when trying to read from a cassandra decimal column using the C# driver:

System.ArgumentOutOfRangeException: CLR Decimal structure can not represent numbers with a scale greater than 28


Is there a workaround for this? I can't see any way of passing a cast through the driver.


Thanks,
George

driver
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Erick Ramirez avatar image Erick Ramirez ♦♦ commented ·

@george.ricketts_175787 just acknowledging your question and I'll look into it. Cheers!

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1 Answer

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joao.reis answered

Hi, you can create a custom type serializer that deserializes Cassandra's decimal to your custom type and serializes your type into Cassandra's decimal. You can look at this implementation for some pointers:

https://github.com/datastax/csharp-driver/blob/d14c6b4f90e6ccb4087c32a2444d6b7ce1487793/src/Cassandra.Tests/Extensions/Serializers/BigDecimalSerializer.cs#L28-L50

This specific BigDecimalSerializer is just a basic implementation that is used in our driver's test suite, we haven't tested it for production use. The BigDecimal.ToString() method has huge memory issues in case the value is ridiculously large for example.

To use a custom type serializer you can add it to the Builder like this: 

var builder = Cluster.Builder()
                     .AddContactPoint(TestCluster.InitialContactPoint)
                     .WithTypeSerializers(new TypeSerializerDefinitions()
                         .Define(new BigDecimalSerializer()));
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