Scala1: Scala is craaazy

I finished scala course provided by Martin Odersky.  And just want to test them in some real case scenario. I had quite easy task: there is csv file, with headers, which need to be imported to database. Normal times when I used java I prepared myself for few days of coding. Typical steps are:

1. csv: find/list java csv processing libraries
2. csv: read / investigate few of them
3. csv: start playing, when one do not work as expected - check another one
4. db: fight with proper driver
5. db: find how to connect
6. db: prepare statements/sqls/ etc..
7. finally connect csv+db into one solution, and make it work smoothly

And after few days I would have working solution with probably few hundred lines of code...(not to mention tests/documentation).

In scala (and I am novice):
  1. created my single object "importer.scala"
  2. whole csv solution finished with adding to my build.sbt file single line:

libraryDependencies += "com.github.tototoshi" %% "scala-csv" % "1.1.2"

as my csv file using ";" as separator I put :

  implicit object MyFormat extends DefaultCSVFormat {
    override val delimiter: Char = ';'  }

then to main function I added 2 lines of code:

    val reader = CSVReader.open("myfile.csv")(MyFormat)
    val full = reader.allWithHeaders

and ... that is it - whole csv solution done in less than 15 mins! (and yes in java I also used sbt like solution - i.e.:maven)

  3. DB part: 

Connection - again to build.sbt, added just one line (I'm using MySQL):

libraryDependencies += "mysql" % "mysql-connector-java" % "5.1.34"

..  and again to main function just added database connection

 val dbc = "jdbc:mysql://localhost:3306/mydb?user=me&password=123"
    Class.forName("com.mysql.jdbc.Driver")   

val conn = DriverManager.getConnection(dbc)

and coding ... lets go ;-) :

    try {
      full.foreach(fields => processFields(fields, conn))
    } finally {
      conn.close
    }

I know that I could do everything inside "full.foreach" but I had some old java habits to create methods for different actions... so I just added processFields function.

  def processFields(in: Map[String, String], conn: java.sql.Connection) {
    val l: MutableList[String] = new MutableList[String]()
    fieldTypes.foreach(f =>
      l += (in.get(f).get).replace("\"", "\\\""))
    val sql = "INSERT INTO temp_products (" + myTypes.mkString(",") +      ") VALUES ( " + "\"" + l.mkString("\",\"") + "\")"
    val prep = conn.prepareStatement(sql)
    prep.executeUpdate
  } 

As you see I had issue with ["] sign - which sometimes appeared inside csv fields.
This is plain/native sql - and whole solution takes me less than 2 hours.

Must say: I was little disappointed with ... so little effort to make things work.
And all I had is 60 lines of code - I really don't see reason to write comments/documentation as this is so obvious (if you know scala) that basically anything more will be overhead.

In next post I will show you about slick - proper DB/ORM mapping in scala and .. how easy is to do reverse engineering - generate objects from DB tables and do some crazy sqls without sql ;-)