public static void Main()
{
// Problem 2. Export the Rivers as JSON
// Write a C# application based on your EF data model for exporting all rivers along with their countries
// in the following JSON format:
// [{ "riverName": "Nile", "riverLength": 6650, "countries": ["Burundi","Democratic Republic of the Congo","Egypt","Eritrea","Ethiopia","Kenya","Rwanda","South Sudan","Sudan","Tanzania","Uganda"] },
// { "riverName": "Amazon", "riverLength": 6400, "countries": ["Bolivia","Brazil","Colombia","Ecuador","Guyana","Peru","Venezuela"] },
// { "riverName": "Yangtze", "riverLength": 6300, "countries":["China"] },
// …
// ]
// 1. Write the output in a JSON file named rivers.json. Include in the output the rivers with no countries
// (if any). The JSON file code formatting is not important. - 8 score
// 2. Order the rivers by length (from the longest) and the countries for each river alphabetically. - 3 score
// 3. For better performance, ensure your program executes a single DB query and retrieves from the database
// only the required data (without unneeded rows and columns).
using (var context = new GeographyEntities())
{
var rivers = context.Rivers
.OrderByDescending(r=>r.Length)
.Select(r => new
{
riverName = r.RiverName,
riverLength = r.Length,
countries = r.Countries
.OrderBy(c=>c.CountryName)
.Select(c => c.CountryName)
});
var json = new JavaScriptSerializer().Serialize(rivers);
File.WriteAllText("rivers.json", json);
}
}
public static void Main()
{
// Problem 3. Export Monasteries by Country as XML
// Write a C# application based on your EF data model for exporting all monasteries by country in a XML file
// named monasteries.xml in the following XML format:
//
// <?xml version="1.0" encoding="utf-8"?>
// <monasteries>
// <country name="Bhutan">
// <monastery>Taktsang Palphug Monastery</monastery>
// </country>
// <country name="Bulgaria">
// <monastery>Bachkovo Monastery “Virgin Mary”</monastery>
// <monastery>Rila Monastery “St. Ivan of Rila”</monastery>
// <monastery>Troyan Monastery “Holy Mother's Assumption”</monastery>
// </country>
// …
// </monasteries>
//
// 1. Exclude all countries with no monasteries. Use an XML parser by choice. - 8 score
// 2. Order the countries alphabetically and the monasteries in each country also alphabetically. - 3 score
// 3. For better performance, ensure your program executes a single DB query and retrieves from the database
// only the required data (without unneeded rows and columns). - 4 score
using (var context = new GeographyEntities())
{
var countries = context.Countries
.Where(c => c.Monasteries.Any())
.OrderBy(c => c.CountryName)
.Select(c => new
{
name = c.CountryName,
monasteries = c.Monasteries
.OrderBy(m => m.Name)
.Select(m => m.Name)
});
var xmlDoc = new XElement("monasteries");
foreach (var country in countries)
{
xmlDoc.Add(
new XElement("country",
new XAttribute("name", country.name),
from m in country.monasteries
select new XElement("monastery", m)));
}
xmlDoc.Save("monasteries.xml");
}
}
public static void Main()
{
// Problem 1. Entity Framework Mappings (Database First)
// Create an Entity Framework (EF) data model of the existing database (map the database tables to C# classes).
// Use the "database first" model in EF. To test your EF data model, list all continent names.
using (var context = new GeographyEntities())
{
var continentsNames = context.Continents.Select(c => c.ContinentName);
foreach (var continentName in continentsNames)
{
Console.WriteLine(continentName);
}
}
using (var context = new GeographyEntities())
{
var continents = context.Continents;
foreach (var continent in continents)
{
Console.WriteLine(continent.ContinentName);
}
}
}
public static void Main()
{
// Problem 4. Import Rivers from XML
// Write a C# application based on your EF data model for importing into the DB a set of rivers given
// in the XML file rivers.xml.
// The name, length and outflow elements are mandatory. The drainage-area, average-discharge and
// countries elements are optional.
// 1. You should parse the XML and throw an exception in case of incorrect data, e.g. when a required
// element is missing or an invalid value is given. The size of the XML file will be less than 10 MB.
// Use an XML parser by choice. - 8 score
// 2. You should correctly import the rivers into the DB. - 7 score
// 3. You should correctly import the countries for each river into the DB. - 5 score
var xmlDoc = XElement.Load("../../rivers.xml");
using (var context = new GeographyEntities())
{
foreach (var riverNode in xmlDoc.Elements())
{
var river = new River();
try
{
river.RiverName = riverNode.Element("name").Value;
river.Length = int.Parse(riverNode.Element("length").Value);
river.Outflow = riverNode.Element("outflow").Value;
if (riverNode.Element("drainage-area") != null)
{
river.DrainageArea = int.Parse(riverNode.Element("drainage-area").Value);
}
if (riverNode.Element("average-discharge") != null)
{
river.AverageDischarge = int.Parse(riverNode.Element("average-discharge").Value);
}
if (riverNode.Descendants("country").Any())
{
foreach (var country in riverNode.Descendants("country"))
{
Console.WriteLine(country);
var countryCode =
context.Countries.First(c => c.CountryName == country.Value);
river.Countries.Add(countryCode);
}
}
}
catch (NullReferenceException e)
{
throw new ArgumentNullException("Missing mandatory data in XML file");
}
catch (FormatException e)
{
throw new ArgumentException("Data provided in XML file are not in correct format");
}
context.Rivers.Add(river);
}
context.SaveChanges();
}
}
