public Book[] GetBooksFromGivenBookScores(IEnumerable <string> bookIds)
{
using (var db = new BooksRecomendationsEntities())
{
return(db.Books.Where(x => bookIds.Contains(x.ISBN)).ToArray());
}
}
public Book[] GetBooksReadByUser(User user)
{
using (var db = new BooksRecomendationsEntities())
{
return(db.BooksRatings.AsNoTracking().Where(x => x.UserId == user.UserId).Select(z => z.Book).ToArray());
}
}
public User[] GetAllUsersWithRatedBooks()
{
using (var db = new BooksRecomendationsEntities())
{
return(db.BooksRatings.AsNoTracking().Select(x => x.User).Distinct().ToArray());
}
}
public IEnumerable <string> GetBooksIdsRatedByAtLeastNUsers(int n)
{
using (var db = new BooksRecomendationsEntities())
{
var books = db.BooksRatings.AsNoTracking().GroupBy(y => y.ISBN);
return(books.Where(x => x.Count() >= n).OrderByDescending(x => x.Count()).Select(x => x.Key).ToArray());
}
}
public string[] GetBooksIdsRatedByAtLeastNUsers(string[] ids, int n)
{
using (var db = new BooksRecomendationsEntities())
{
var books = db.BooksRatings.AsNoTracking().Where(x => ids.Contains(x.ISBN)).GroupBy(y => y.ISBN);
return(books.Where(x => x.Count() >= n).Select(x => x.Key).ToArray());
}
}
public List <UserSimilar> GetUserNeighbors(int userId, int settingsVersion)
{
using (var db = new BooksRecomendationsEntities())
{
return(db.UserSimilars.AsNoTracking()
.Where(x => x.UserId == userId && x.ParametersSet == settingsVersion)
.ToList());
}
}
public void AddSimilarUsers(List <UsersSimilarity> similarUsers, int settingsVersion)
{
using (var db = new BooksRecomendationsEntities())
{
var users = similarUsers.Select(x => MapToUserSimilarDataModel(x, settingsVersion)).ToList();
db.UserSimilars.AddRange(users);
db.SaveChanges();
}
}
public void AddTestResult(List <BookScore> score, int settingVersion)
{
using (var db = new BooksRecomendationsEntities())
{
var result = score.Where(x => x.PredictedRate > 0)
.Select(bookScore => MapScoreToTest(bookScore, settingVersion));
db.Tests.AddRange(result);
db.SaveChanges();
}
}
public int[] GetAllUsersWithComputedSimilarity(int settingVersion)
{
using (var db = new BooksRecomendationsEntities())
{
return(db.UserSimilars.AsNoTracking()
.Where(x => x.ParametersSet == settingVersion)
.Select(x => x.UserId)
.Distinct()
.ToArray());
}
}
public Book[] GetRecommendedBooksForUser(int userId)
{
using (var db = new BooksRecomendationsEntities())
{
return(db.BookRecomendations
.Where(x => x.UserId == userId)
.OrderByDescending(x => x.PredictedRate)
.Select(b => b.Book)
.ToArray());
}
}
public List <int> GetUsersWhoRatedAnyOfGivenBooks(string[] bookIds)
{
using (var db = new BooksRecomendationsEntities())
{
return(db.BooksRatings.AsNoTracking()
.Where(x => bookIds.Contains(x.ISBN))
.Select(x => x.UserId)
.Distinct()
.ToList());
}
}
public double?GetAverageRateForUser(int userId)
{
using (var db = new BooksRecomendationsEntities())
{
var ratings = db.BooksRatings.AsNoTracking().Where(x => x.UserId == userId).ToArray();
if (ratings.Length == 0)
{
return(null);
}
var average = ratings.Average(x => x.Rate);
return(Math.Round(average, 2));
}
}
public BookScore[] GetBooksRatesByUserId(int userId)
{
using (var db = new BooksRecomendationsEntities())
{
return(db.BooksRatings.AsNoTracking()
.Where(x => x.UserId == userId)
.AsEnumerable()
.Select(x => new BookScore {
BookId = x.ISBN, Rate = x.Rate, UserId = userId
})
.ToArray());
}
}
public void SaveParametersSet(Parameter parameter)
{
using (var db = new BooksRecomendationsEntities())
{
var temp = db.Parameters.Find(parameter.Id);
if (temp == null)
{
db.Parameters.Add(parameter);
}
db.SaveChanges();
}
}
public List <int> GetUserIdsWithNorMoreRatedBooks(int n)
{
using (var db = new BooksRecomendationsEntities())
{
var users = db.BooksRatings
.AsNoTracking()
.Where(x => x.User.BooksRatings.Count >= n && x.User.BooksRatings.Count < 1000)
.Select(x => x.UserId)
.ToList();
return(users.Distinct()
.ToList());
}
}
public void AddTestResults(List <BookScore[]> scores, int settingVersion)
{
using (var db = new BooksRecomendationsEntities())
{
var result = new List <Test>();
foreach (var score in scores)
{
result.AddRange(score.Select(bookScore => MapScoreToTest(bookScore, settingVersion)));
}
db.Tests.AddRange(result);
db.SaveChanges();
}
}
public void AddRecommendedBooksForUser(BookScore[] books, int userId)
{
using (var db = new BooksRecomendationsEntities())
{
//delete any if exist
db.Database.ExecuteSqlCommand("Delete from BookRecomendation where UserId=@userId",
new SqlParameter("@userId", userId));
if (books != null)
{
db.BookRecomendations.AddRange(books.Select(x => MapToBookRecommendationModel(x, userId)));
}
db.SaveChanges();
}
}
public Parameter GetParameters(int settingsVersion)
{
using (var db = new BooksRecomendationsEntities())
{
var settings = db.Parameters.Where(x => x.Id == settingsVersion).ToList();
return(settings.Select(x =>
new Parameter
{
BookPopularity = x.BookPopularity,
DistanceSimilarityType = x.DistanceSimilarityType,
DistanceType = x.DistanceType,
Id = x.Id,
Kneigbors = x.Kneigbors,
NumberOfBooksEachUserRated = x.NumberOfBooksEachUserRated
})
.FirstOrDefault());
}
}