Reading JSON files

Reading single file

Start by importing scalaql:

import scalaql._

// Docs classes
import scalaql.docs.Hogwarts._
import scalaql.docs.DocUtils._

// Imports for examples
import java.nio.file.Paths
import io.circe.generic.auto._

Assume you have a JSON file like the following:

val studentsPath = Paths.get("docs/src/main/resources/students.json")
// studentsPath: java.nio.file.Path = docs/src/main/resources/students.json

printFile(studentsPath)
// {"name":"Harry","age":19,"faculty":"Gryffindor","grade":85.1,"specialization":"learning","birthDay":"1980-07-31"}
// {"name":"Ron","age":18,"faculty":"Gryffindor","grade":66.2,"specialization":"eating","birthDay":"1980-05-01"}
// {"name":"Hermione","age":18,"faculty":"Gryffindor","grade":99.6,"specialization":"learning","birthDay":"1979-09-17"}
// {"name":"Draco","age":18,"faculty":"Slytherin","grade":85.1,"specialization":"trolling","birthDay":"1980-06-05"}
// {"name":"Cedric","age":17,"faculty":"Hufflepuff","grade":90.1,"specialization":"young dying","birthDay":"1977-10-01"}

First, you defined a Query as usual:

val query =
  select[Student]
    .where(_.age >= 18)
// query: Query[From[Student], Student] = FROM(Hogwarts::Student) -> WHERE

Then you could specify to run the Query on a json file instead of a Scala collection:

query
  .show(truncate=false)
  .run(
    from(
      json.read[Student].file(studentsPath)
    )
  )
// +--------+---+----------+-----+--------------+----------+
// |name    |age|faculty   |grade|specialization|birthDay  |
// +--------+---+----------+-----+--------------+----------+
// |Harry   |19 |Gryffindor|85.1 |learning      |1980-07-31|
// |Ron     |18 |Gryffindor|66.2 |eating        |1980-05-01|
// |Hermione|18 |Gryffindor|99.6 |learning      |1979-09-17|
// |Draco   |18 |Slytherin |85.1 |trolling      |1980-06-05|
// +--------+---+----------+-----+--------------+----------+
//