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scalaimplicitscala-catsdoobie

Doobie cannot find or construct a Read instance for Type of case class with Timestamp

Given a case class representation of a data row with a java.sql.Timestamp:

 case class ExampleRow(id: String, ts: Timestamp)

And query expecting an ExampleRow:

 import doobie._
 import doobie.implicits._
 import doobie.postgres.implicits._

 val queryExampleRows = 
   sql"select * from example".query[ExampleRow].to[List]

There is a resulting compile error:

Cannot find or construct a Read instance for type:

ExampleRow

This is surprising given that the documentation claims that Timestamp should work. Further, I know that the Timestamp is the cause because removing that member results in the code compiling.

How can a case class contain a Timestamp and capable of being queried by doobie?

There is a similar question but I cannot figure out if it applicable to my question since it involves a type parameter T and not a concrete type like Timestamp.

Thank you in advance for your consideration and response.

Solution

  • Per the suggestion from the comments the problem was solved by transitioning the type from java.sql.Timestamp to java.time.Instant.