Generate a Spark StructType / Schema from a case class

Question

If I wanted to create a `StructType` (i.e. a `DataFrame.schema`) out of a `case class`, is there a way to do it without creating a `DataFrame`? I can easily do: ``` case class TestCase(id: Long) val schema = Seq[TestCase]().toDF.schema ``` But it seems overkill to actually create a `DataFrame` when all I want is the schema. (If you are curious, the reason behind the question is that I am defining a `UserDefinedAggregateFunction`, and to do so you override a couple of methods that return `StructTypes` and I use case classes.)

Accepted Answer

You can do it the same way `SQLContext.createDataFrame` does it:

```
import org.apache.spark.sql.catalyst.ScalaReflection
val schema = ScalaReflection.schemaFor[TestCase].dataType.asInstanceOf[StructType]
```

Generate a Spark StructType / Schema from a case class

Solution

Problem