Work with databases (DB)

import android.content.Context
import android.database.sqlite.SQLiteDatabase
import android.database.sqlite.SQLiteOpenHelper

class DataBaseHelper(context: Context, dbName: String):
    SQLiteOpenHelper(context, dbName, null1) {

    override fun onCreate(db: SQLiteDatabase?) {}

    override fun onUpgrade(db: SQLiteDatabase?, oldVersion: Int,
                          newVersion: Int) {}
}

//Connect to the database
val dbHelper = DataBaseHelper(
    context,
    dbPath + "DatabaseName.sqlite"
)

//SQL query execution
val db = dbHelper.readableDatabase
val cursor = db.rawQuery(
    """SELECT
         Language, Percentage
       FROM countrylanguage
       WHERE CountryCode = 'RUS'
       ORDER BY Percentage DESC"""null)

//Get first row
cursor.moveToFirst()
println(cursor.getString(0) +
    ": " + cursor.getDouble(1))

// Get all rows
while (!cursor.isAfterLast()) {
    println(cursor.getString(0) +
        ": " + cursor.getDouble(1))
    cursor.moveToNext()
}

//Close the connection
cursor.close()