static void Main(string[] args)
{
// .ReverseMap() се ползва когато искаме от вю модел да направиме клас, който после да вкараме в базата.
// Примерно когато потребителя е въвел нова песен от приложението, тя после за да се вкара в базата трябва да се обърне на клас, който го има в db контекста.
//dotnet ef dbcontext scaffold "Server=.\SQLEXPRESS;Database=MusicX;Integrated Security=true" Microsoft.EntityFrameworkCore.SqlServer -o Models
var config = new MapperConfiguration(config =>
{
config.CreateMap <Song, SongNameDTO>();
});
var mapper = config.CreateMapper();
var db = new MusicXContext();
Song song = db.Songs.Where(x => x.Id == 4)
.FirstOrDefault();
var songDTO = mapper.Map <SongNameDTO>(song);
Console.WriteLine(songDTO);
}
public static void Main(string[] args)
{
var db = new MusicXContext();
// Example - Executing Native SQL Query
var songs = db.Songs.FromSqlRaw("SELECT * FROM Songs WHERE Id < 5").ToList();
foreach (var song in songs)
{
Console.WriteLine($"{song.Id} - {song.Name}");
}
// Example - Eager loading
var artists = db
.Artists
.Include(a => a.SongArtists)
.ThenInclude(sa => sa.Song)
.Take(10)
.ToList();
foreach (var artist in artists)
{
Console.WriteLine($"{artist.Name} - {artist.SongArtists.First().Song.Name}");
}
}
static void Main(string[] args)
{
Console.OutputEncoding = System.Text.Encoding.UTF8;
var context = new MusicXContext();
var config = new MapperConfiguration(cfg =>
cfg.AddProfile(new SongProfile())
);
var mapper = config.CreateMapper();
var song = context.Songs.FirstOrDefault();
var songDTO = mapper.Map <SongDTO>(song);
//var songReverse = mapper.Map<SongDTO, Song>(songDTO);
var songDTO2 = context.Songs
.Where(x => x.Source.Name.StartsWith("Us"))
.ProjectTo <SongDTO>(config).ToList();
Console.WriteLine(JsonConvert.SerializeObject(songDTO, Formatting.Indented));
}
static void Main(string[] args)
{
// dotnet ef dbcontext scaffold "Server=.\SQLEXPRESS;Database=SoftUni;Integrated Security=true" Microsoft.EntityFrameworkCore.SqlServer -o Models - f - d
Console.OutputEncoding = Encoding.Unicode; // конзолата да дава кирилица !!!
var db = new MusicXContext();
// Console.WriteLine(db.Songs.Count());
// по дефолт се взимат само примитивните типове от данни !!!
// WHERE
//var songs = db.Songs.Where(x => x.Name.StartsWith("Н")).ToList();
//Console.WriteLine(songs.Count());
//var songs = db.Songs.Where(x => x.Source.Name == "User").ToList();
//foreach (var song in songs)
//{
// Console.WriteLine(song.Name);
//}
// SELECT
var songs = db.Songs.Where(x => x.Source.Name == "User")
.Select(x => new
{
x.Name,
Source = x.Source.Name,
Artists = string.Join(", ", x.SongArtists.Select(a => a.Artist.Name)),
})
.ToList();
foreach (var song in songs)
{
Console.WriteLine(song.Artists + " - " + song.Name);
}
// WITH .SELECT() => anonymous type
// 1. (+) Navigational properties in the lambda expression
// 2. (+) Get only the columns we need
// 3. (-) No update/delete
// NO .SELECT(): => original entity
// 1. (-)No Access to navigational properties
// 2. (-)Get All colums for entity
// 3. (+) update/delete intity / SaveChanges()
// anonymous type не се траква change tracker-a (savechanges!)
}
public static void Main(string[] args)
{
var db = new MusicXContext();
var config = new MapperConfiguration(cfg =>
{
cfg.CreateMap <Song, SongInfoDto>();
});
var mapper = config.CreateMapper();
Song song = db.Songs.Where(x => x.Id == 10).First();
var songDto = mapper.Map <SongInfoDto>(song);
}
public static void Main(string[] args)
{
Console.OutputEncoding = Encoding.Unicode;
var context = new MusicXContext();
// Example 1 - Aggregation
var artists1 = context
.Artists
.Where(x => x.SongArtists.Count() > 50)
.OrderByDescending(x => x.SongArtists.Count())
.Select(x => new
{
x.Name,
Count = x.SongArtists.Count()
})
.Take(5)
.ToList();
foreach (var artist in artists1)
{
Console.WriteLine(artist);
}
// Example 2 - Join
var songs = context
.Songs
.Join(
context.Sources,
x => x.SourceId,
x => x.Id,
(song, source) => new
{
SongName = song.Name,
SourceName = source.Name
}
)
.Take(5)
.ToList();
foreach (var song in songs)
{
Console.WriteLine(song);
}
// Example 3 - Group
var groups = context
.Artists
.GroupBy(x => x.Name.Substring(0, 1))
.Select(x => new
{
FirstLetter = x.Key,
Count = x.Count(),
})
.ToList();
foreach (var group in groups)
{
Console.WriteLine(group);
}
// Example 4 - SelectMany
var songs2 = context
.Artists
.SelectMany(x => x.SongArtists.Select(sa => x.Name + " - " + sa.Song.Name))
.Take(10)
.ToList();
foreach (var song in songs2)
{
Console.WriteLine(song);
}
}
