public static void Main(string[] args)
{
using (var context = new PlutoContext())
{
// LINQ syntax
Console.WriteLine(@"LINQ Syntax");
Console.WriteLine();
QueryUsingLinqSyntax(context);
// Extension syntax
Console.WriteLine(@"Extension Syntax");
Console.WriteLine();
QueryUsingExtensionSyntax(context);
// Repositories
QueryUsingRepositories();
}
}
/// <summary>
/// Queries using linq syntax.
/// </summary>
/// <param name="context">The context.</param>
private static void QueryUsingLinqSyntax(PlutoContext context)
{
#region [Filter by CourseID]
Console.WriteLine(@"#Filter by CourseID");
Console.WriteLine();
var filterByCourseID =
from course in context.Courses
where course.ID > 3
orderby course.ID descending
select course;
foreach (var row in filterByCourseID)
{
Console.WriteLine($@" {row.ID}: {row.Name} ({row.Author.Name})");
}
Console.WriteLine();
#endregion
#region [Filter by CourseName]
Console.WriteLine(@"#Filter by CourseName");
Console.WriteLine();
var filterByCourseName =
from course in context.Courses
where course.Name.Contains("c#")
orderby course.Name
select course;
foreach (var row in filterByCourseName)
{
Console.WriteLine($@" {row.ID}: {row.Name} ({row.Author.Name})");
}
Console.WriteLine();
#endregion
#region [Filter by CourseLevel]
Console.WriteLine(@"#Filter by CourseLevel");
Console.WriteLine();
var filterByCourseLevel =
from course in context.Courses
where course.Level == CourseLevel.Beginner
orderby course.Author.Name, course.FullPrice
select course;
foreach (var row in filterByCourseLevel)
{
Console.WriteLine($@" {row.ID}: {row.Name} ({row.FullPrice} - {row.Author.Name})");
}
Console.WriteLine();
#endregion
#region [Anonymous Objects]
Console.WriteLine(@"#Anonymous Objects");
Console.WriteLine();
var anonymousObjects =
from course in context.Courses
where course.ID > 3
orderby course.ID descending
select new
{
CourseID = course.ID,
CourseName = course.Name,
AuthorName = course.Author.Name
};
foreach (var row in anonymousObjects)
{
Console.WriteLine($@" {row.CourseID}: {row.CourseName} ({row.AuthorName})");
}
Console.WriteLine();
#endregion
#region [Group by Level]
Console.WriteLine(@"#Group by Level");
Console.WriteLine();
var groupCoursesByLevel =
from course in context.Courses
group course by course.Level into courseGroup
select courseGroup;
foreach (var row in groupCoursesByLevel)
{
Console.WriteLine($@" {row.Key} ({row.Count()})");
foreach (var course in row)
{
Console.WriteLine($@" {course.ID}: {course.Name} ({course.Author.Name})");
}
Console.WriteLine();
}
#endregion
#region [Group Join]
Console.WriteLine(@"#Group Join");
Console.WriteLine();
var groupJoinAuthorsWithCourses =
from author in context.Authors
join course in context.Courses on author.ID equals course.AuthorID into authorGroup
select new
{
AuthorID = author.ID,
AuthorName = author.Name,
Courses = authorGroup
};
foreach (var row in groupJoinAuthorsWithCourses)
{
Console.WriteLine($@" {row.AuthorID}: {row.AuthorName} ({row.Courses.Count()})");
}
Console.WriteLine();
#endregion
#region [Cross Join]
Console.WriteLine(@"#Cross Join");
Console.WriteLine();
var crossJoinAuthorsWithCourses =
from author in context.Authors
from course in context.Courses
select new
{
AuthorID = author.ID,
AuthorName = author.Name,
CourseID = course.ID,
CourseName = course.Name
};
foreach (var row in crossJoinAuthorsWithCourses)
{
Console.WriteLine($@" {row.AuthorID}: {row.AuthorName} /{row.CourseID} : {row.CourseName})");
}
Console.WriteLine();
#endregion
#region [Join]
Console.WriteLine(@"#Join");
Console.WriteLine();
var joinCoursesWithAuthors =
from course in context.Courses
join author in context.Authors on course.AuthorID equals author.ID
select new
{
CourseID = course.ID,
CourseName = course.Name,
AuthorID = author.ID,
AuthorName = author.Name
};
foreach (var row in joinCoursesWithAuthors)
{
Console.WriteLine($@" {row.CourseID}: {row.CourseName} ({row.AuthorName})");
}
Console.WriteLine();
#endregion
}
/// <summary>
/// Queries using extension syntax.
/// </summary>
/// <param name="context">The context.</param>
private static void QueryUsingExtensionSyntax(PlutoContext context)
{
#region [Filter by CourseID]
Console.WriteLine(@"#Filter by CourseID");
Console.WriteLine();
var filterByCourseID = context.Courses
.Where(course => course.ID > 3)
.OrderByDescending(course => course.ID);
foreach (var row in filterByCourseID)
{
Console.WriteLine($@" {row.ID}: {row.Name} ({row.Author.Name})");
}
Console.WriteLine();
#endregion
#region [Filter by CourseName]
Console.WriteLine(@"#Filter by CourseName");
Console.WriteLine();
var filterCoursesByName = context.Courses
.Where(course => course.Name.Contains("c#"))
.OrderBy(course => course.Name);
foreach (var row in filterCoursesByName)
{
Console.WriteLine($@" {row.ID}: {row.Name} ({row.Author.Name})");
}
Console.WriteLine();
#endregion
#region [Filter by CourseLevel]
Console.WriteLine(@"#Filter by CourseLevel");
Console.WriteLine();
var filterCoursesByLevel = context.Courses
.Where(course => course.Level == CourseLevel.Beginner)
.OrderBy(course => course.Author.Name)
.ThenBy(course => course.FullPrice);
foreach (var row in filterCoursesByLevel)
{
Console.WriteLine($@" {row.ID}: {row.Name} ({row.FullPrice} - {row.Author.Name})");
}
Console.WriteLine();
#endregion
#region [Anonymous Objects]
Console.WriteLine(@"#Anonymous Objects");
Console.WriteLine();
var anonymousObjects = context.Courses.Select(course => new
{
CourseID = course.ID,
CourseName = course.Name,
CourseTags = course.Tags.ToList()
});
foreach (var row in anonymousObjects)
{
Console.Write($@" {row.CourseID}: {row.CourseName} ({row.CourseTags.Count}:");
for (int i = 0; i < row.CourseTags.Count; i++)
{
var tag = row.CourseTags[i];
Console.Write(i != row.CourseTags.Count - 1 ? $@"{tag.Name}, " : $@"{tag.Name}");
}
Console.WriteLine(@")");
}
Console.WriteLine();
#endregion
#region [Group by Level]
Console.WriteLine(@"#Group by Level");
Console.WriteLine();
var groupCoursesByLevel = context.Courses
.GroupBy(course => course.Level);
foreach (var row in groupCoursesByLevel)
{
Console.WriteLine($@" {row.Key} ({row.Count()})");
foreach (var course in row)
{
Console.WriteLine($@" {course.ID}: {course.Name} ({course.Author.Name})");
}
Console.WriteLine();
}
#endregion
#region [Group Join]
Console.WriteLine(@"#Group Join");
Console.WriteLine();
var groupJoinAuthorsWithCourses = context.Authors.GroupJoin
(
context.Courses,
author => author.ID,
course => course.AuthorID,
(author, courses) => new
{
AuthorID = author.ID,
AuthorName = author.Name,
Courses = courses
}
);
foreach (var row in groupJoinAuthorsWithCourses)
{
Console.WriteLine($@" {row.AuthorID}: {row.AuthorName} ({row.Courses.Count()})");
}
Console.WriteLine();
#endregion
#region [Cross Join]
Console.WriteLine(@"#Cross Join");
Console.WriteLine();
var crossJoinAuthorsWithCourses = context.Authors.SelectMany
(
author => context.Courses,
(author, course) => new
{
CourseID = course.ID,
CourseName = course.Name,
AuthorID = author.ID,
AuthorName = author.Name
}
);
foreach (var row in crossJoinAuthorsWithCourses)
{
Console.WriteLine($@" {row.AuthorID}: {row.AuthorName} /{row.CourseID} : {row.CourseName})");
}
Console.WriteLine();
#endregion
#region [Join]
Console.WriteLine(@"#Join");
Console.WriteLine();
var joinCoursesWithAuthors = context.Courses.Join
(
context.Authors,
course => course.AuthorID,
author => author.ID,
(course, author) => new
{
CourseID = course.ID,
CourseName = course.Name,
AuthorID = author.ID,
AuthorName = author.Name
}
);
foreach (var course in joinCoursesWithAuthors)
{
Console.WriteLine($@" {course.CourseID}: {course.CourseName} ({course.AuthorName})");
}
Console.WriteLine();
#endregion
#region [Partitions]
Console.WriteLine(@"#Partition by CourseID");
Console.WriteLine();
var partitionByCourseID = context.Courses
.OrderByDescending(course => course.ID)
.Skip(3).Take(3);
foreach (var row in partitionByCourseID)
{
Console.WriteLine($@" {row.ID}: {row.Name} ({row.Author.Name})");
}
Console.WriteLine();
#endregion
#region [Element Operators]
Console.WriteLine(@"#Element Operators");
Console.WriteLine();
var firstCourse = context.Courses
.OrderBy(course => course.Level)
.FirstOrDefault(course => course.FullPrice > 100);
Console.WriteLine($@" {firstCourse?.ID}: {firstCourse?.Name} ({firstCourse?.Author.Name})");
Console.WriteLine();
var lastCourse = context.Courses
.OrderByDescending(course => course.Level)
.FirstOrDefault(course => course.FullPrice > 100);
Console.WriteLine($@" {lastCourse?.ID}: {lastCourse?.Name} ({lastCourse?.Author.Name})");
Console.WriteLine();
bool allAbove100Dollars = context.Courses.All(course => course.FullPrice > 100);
bool anyBelow50Dollars = context.Courses.Any(course => course.FullPrice < 50);
Console.WriteLine($@"All above 100? {allAbove100Dollars}");
Console.WriteLine($@"Any below 50? {anyBelow50Dollars}");
Console.WriteLine();
float leastExpensiveCoursePrice = context.Courses.Min(course => course.FullPrice);
float mostExpensiveCoursePrice = context.Courses.Max(course => course.FullPrice);
float averageCoursePrice = context.Courses.Average(course => course.FullPrice);
Console.WriteLine($@"Least expensive price: {leastExpensiveCoursePrice}");
Console.WriteLine($@"Most expensive price: {mostExpensiveCoursePrice}");
Console.WriteLine($@"Average price: {averageCoursePrice}");
Console.WriteLine();
#endregion
}
