Wyrażenia zapytań
Wyrażenia zapytań umożliwiają wykonywanie zapytań względem źródła danych i umieszczanie danych w żądanym formularzu. Wyrażenia zapytań zapewniają obsługę LINQ w języku F#.
Składnia
query { expression }
Uwagi
Wyrażenia zapytania są typem wyrażenia obliczeniowego podobnego do wyrażeń sekwencji. Tak jak określasz sekwencję, podając kod w wyrażeniu sekwencji, należy określić zestaw danych, podając kod w wyrażeniu zapytania. W wyrażeniu sekwencji słowo kluczowe identyfikuje dane, yield
które mają być zwracane w ramach wynikowej sekwencji. W wyrażeniach select
zapytania słowo kluczowe wykonuje tę samą funkcję. Oprócz słowa kluczowego select
język F# obsługuje również wiele operatorów zapytań, które są podobne do części instrukcji SQL SELECT. Oto przykład prostego wyrażenia zapytania wraz z kodem, który łączy się ze źródłem Northwind OData.
// Use the OData type provider to create types that can be used to access the Northwind database.
// Add References to FSharp.Data.TypeProviders and System.Data.Services.Client
open Microsoft.FSharp.Data.TypeProviders
type Northwind = ODataService<"http://services.odata.org/Northwind/Northwind.svc">
let db = Northwind.GetDataContext()
// A query expression.
let query1 =
query {
for customer in db.Customers do
select customer
}
// Print results
query1
|> Seq.iter (fun customer -> printfn "Company: %s Contact: %s" customer.CompanyName customer.ContactName)
W poprzednim przykładzie kodu wyrażenie zapytania jest w nawiasach klamrowych. Znaczenie kodu w wyrażeniu to, zwracanie każdego klienta w tabeli Customers w bazie danych w wynikach zapytania. Wyrażenia zapytań zwracają typ, który implementuje IQueryable<T> wartości i IEnumerable<T>, a więc mogą być iterated przy użyciu modułu Seq, jak pokazano w przykładzie.
Każdy typ wyrażenia obliczeniowego jest tworzony na podstawie klasy konstruktora. Klasa konstruktora dla wyrażenia obliczeniowego zapytania to QueryBuilder
. Aby uzyskać więcej informacji, zobacz Wyrażenia obliczeniowe i Klasa QueryBuilder.
Operatory zapytań
Operatory zapytań umożliwiają określenie szczegółów zapytania, takich jak umieszczenie kryteriów dla zwracanych rekordów lub określenie kolejności sortowania wyników. Źródło zapytania musi obsługiwać operator zapytania. Jeśli spróbujesz użyć nieobsługiwanego operatora zapytania, System.NotSupportedException
zostanie zgłoszony.
Wyrażenia, które można przetłumaczyć na język SQL, są dozwolone w wyrażeniach zapytań. Na przykład żadne wywołania funkcji nie są dozwolone w wyrażeniach podczas korzystania z where
operatora zapytania.
Tabela 1 zawiera dostępne operatory zapytań. Ponadto zobacz Tabela2, która porównuje zapytania SQL i równoważne wyrażenia zapytań języka F# w dalszej części tego tematu. Niektóre operatory zapytań nie są obsługiwane przez niektórych dostawców typów. W szczególności dostawca typu OData jest ograniczony do operatorów zapytań, które obsługuje z powodu ograniczeń w usłudze OData.
W tej tabeli założono, że baza danych ma następującą postać:
Kod w poniższych tabelach zakłada również następujący kod połączenia z bazą danych. Projekty powinny dodawać odwołania do zestawów System.Data, System.Data.Linq i FSharp.Data.TypeProviders. Kod tworzący tę bazę danych znajduje się na końcu tego tematu.
open System
open Microsoft.FSharp.Data.TypeProviders
open System.Data.Linq.SqlClient
open System.Linq
open Microsoft.FSharp.Linq
type schema = SqlDataConnection< @"Data Source=SERVER\INSTANCE;Initial Catalog=MyDatabase;Integrated Security=SSPI;" >
let db = schema.GetDataContext()
// Needed for some query operator examples:
let data = [ 1; 5; 7; 11; 18; 21]
Tabela 1. Operatory zapytań
Operator | opis |
---|---|
contains |
Określa, czy wybrane elementy zawierają określony element.
|
count | Zwraca liczbę wybranych elementów.
|
last | Wybiera ostatni element wybranych do tej pory.
|
lastOrDefault | Wybiera ostatni element wybranych do tej pory lub wartość domyślną, jeśli żaden element nie zostanie znaleziony.
|
exactlyOne | Wybiera wybrany do tej pory pojedynczy, określony element. Jeśli istnieje wiele elementów, zgłaszany jest wyjątek.
|
exactlyOneOrDefault | Wybiera pojedynczy, konkretny element wybranych do tej pory lub wartość domyślną, jeśli ten element nie zostanie znaleziony.
|
headOrDefault | Wybiera pierwszy element wybranych do tej pory lub wartość domyślną, jeśli sekwencja nie zawiera żadnych elementów.
|
select | Projektuje każdy z wybranych do tej pory elementów.
|
where | Wybiera elementy na podstawie określonego predykatu.
|
minBy | Wybiera wartość dla każdego wybranego elementu do tej pory i zwraca minimalną wynikową wartość.
|
maxBy | Wybiera wartość dla każdego wybranego elementu do tej pory i zwraca maksymalną wartość wynikową.
|
groupBy | Grupuje elementy wybrane do tej pory zgodnie z określonym selektorem kluczy.
|
sortBy | Sortuje elementy wybrane do tej pory w kolejności rosnącej według danego klucza sortowania.
|
sortByDescending | Sortuje elementy wybrane do tej pory w kolejności malejącej według danego klucza sortowania.
|
thenBy | Wykonuje kolejną kolejność elementów wybranych do tej pory w kolejności rosnącej przez dany klucz sortowania. Ten operator może być używany tylko po , sortBy sortByDescending , thenBy lub thenByDescending .
|
thenByDescending | Wykonuje kolejną kolejność elementów wybranych do tej pory w kolejności malejącej według danego klucza sortowania. Ten operator może być używany tylko po , sortBy sortByDescending , thenBy lub thenByDescending .
|
groupValBy | Wybiera wartość dla każdego elementu wybranego do tej pory i grupuje elementy według danego klucza.
|
join | Koreluje dwa zestawy wybranych wartości na podstawie pasujących kluczy. Należy pamiętać, że kolejność kluczy wokół znaku = zalogowanie wyrażenia sprzężenia jest znacząca. We wszystkich sprzężeniach, jeśli wiersz jest podzielony po symbolu -> , wcięcie musi być wcięcie co najmniej do słowa kluczowego for .
|
groupJoin | Koreluje dwa zestawy wybranych wartości na podstawie pasujących kluczy i grupuje wyniki. Należy pamiętać, że kolejność kluczy wokół znaku = zalogowanie wyrażenia sprzężenia jest znacząca.
|
leftOuterJoin | Koreluje dwa zestawy wybranych wartości na podstawie pasujących kluczy i grupuje wyniki. Jeśli jakakolwiek grupa jest pusta, zamiast tego zostanie użyta grupa z pojedynczą wartością domyślną. Należy pamiętać, że kolejność kluczy wokół znaku = zalogowanie wyrażenia sprzężenia jest znacząca.
|
sumByNullable | Wybiera wartość dopuszczaną do wartości null dla każdego elementu wybranego do tej pory i zwraca sumę tych wartości. Jeśli jakiekolwiek dopuszczanie wartości null nie ma wartości, jest ignorowane.
|
minByNullable | Wybiera wartość dopuszczaną do wartości null dla każdego elementu wybranego do tej pory i zwraca minimalną z tych wartości. Jeśli jakiekolwiek dopuszczanie wartości null nie ma wartości, jest ignorowane.
|
maxByNullable | Wybiera wartość dopuszczaną do wartości null dla każdego elementu wybranego do tej pory i zwraca maksymalną z tych wartości. Jeśli jakiekolwiek dopuszczanie wartości null nie ma wartości, jest ignorowane.
|
averageByNullable | Wybiera wartość dopuszczaną do wartości null dla każdego elementu wybranego do tej pory i zwraca średnią tych wartości. Jeśli jakiekolwiek dopuszczanie wartości null nie ma wartości, jest ignorowane.
|
averageBy | Wybiera wartość dla każdego wybranego elementu do tej pory i zwraca średnią tych wartości.
|
distinct | Wybiera różne elementy z wybranych do tej pory elementów.
|
exists | Określa, czy dowolny wybrany element do tej pory spełnia warunek.
|
find | Wybiera pierwszy wybrany do tej pory element, który spełnia określony warunek.
|
all | Określa, czy wszystkie wybrane elementy do tej pory spełniają warunek.
|
head | Wybiera pierwszy element z wybranych do tej pory.
|
nth | Wybiera element w określonym indeksie spośród wybranych do tej pory.
|
skip | Pomija określoną liczbę wybranych do tej pory elementów, a następnie wybiera pozostałe elementy.
|
skipWhile | Pomija elementy w sekwencji, o ile określony warunek jest spełniony, a następnie wybiera pozostałe elementy.
|
sumBy | Wybiera wartość dla każdego wybranego elementu do tej pory i zwraca sumę tych wartości.
|
take | Wybiera określoną liczbę ciągłych elementów z wybranych do tej pory.
|
takeWhile | Wybiera elementy z sekwencji, o ile określony warunek jest spełniony, a następnie pomija pozostałe elementy.
|
sortByNullable | Sortuje elementy wybrane do tej pory w kolejności rosnącej według danego klucza sortowania dopuszczającego wartość null.
|
sortByNullableDescending | Sortuje elementy wybrane do tej pory w kolejności malejącej według danego klucza sortowania dopuszczającego wartość null.
|
thenByNullable | Wykonuje kolejną kolejność elementów wybranych do tej pory w kolejności rosnącej przez dany klucz sortowania dopuszczający wartość null. Ten operator może być używany tylko natychmiast po wariantach sortBy , , sortByDescending thenBy lub , lub thenByDescending dopuszczanych do wartości null.
|
thenByNullableDescending | Wykonuje kolejną kolejność elementów wybranych do tej pory w kolejności malejącej według danego klucza sortowania dopuszczającego wartość null. Ten operator może być używany tylko natychmiast po wariantach sortBy , , sortByDescending thenBy lub , lub thenByDescending dopuszczanych do wartości null.
|
Porównanie języka Transact-SQL z wyrażeniem zapytania F#
W poniższej tabeli przedstawiono niektóre typowe zapytania Języka Transact-SQL i ich odpowiedniki w języku F#. Kod w tej tabeli zakłada również, że ta sama baza danych co poprzednia tabela i ten sam kod początkowy do skonfigurowania dostawcy typów.
Tabela 2. Transact-SQL i wyrażenia zapytania F#
Transact-SQL (nie uwzględnia wielkości liter) | Wyrażenie zapytania języka F# (z uwzględnieniem wielkości liter) |
---|---|
Zaznacz wszystkie pola z tabeli.
|
|
Zlicz rekordy w tabeli.
|
|
EXISTS
|
|
Grupowanie
|
|
Grupowanie z warunkiem.
|
|
Grupowanie z warunkiem liczby.
|
|
Grupowanie, liczenie i sumowanie.
|
|
Grupowanie, liczenie i porządkowanie według liczby.
|
|
IN zestaw określonych wartości
|
|
LIKE i TOP .
|
|
LIKE z zestawem dopasowania wzorca.
|
|
LIKE z ustawionym wzorcem wykluczeń.
|
|
LIKE w jednym polu, ale wybierz inne pole.
|
|
LIKE z wyszukiwaniem podciągów.
|
|
Proste JOIN z dwiema tabelami.
|
|
LEFT JOIN z dwiema tabelami.
|
|
JOIN Z COUNT
|
|
DISTINCT
|
|
Zliczenie.
|
|
BETWEEN
|
|
OR
|
|
OR z kolejnością
|
|
TOP , OR i porządkowanie.
|
|
UNION z dwóch zapytań.
|
|
Przecięcie dwóch zapytań.
|
|
CASE Warunek.
|
|
Wiele przypadków.
|
|
Wiele tabel.
|
|
Wiele sprzężeń.
|
|
Wiele lewych sprzężeń zewnętrznych.
|
|
Poniższy kod może służyć do utworzenia przykładowej bazy danych dla tych przykładów.
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
USE [master];
GO
IF EXISTS (SELECT * FROM sys.databases WHERE name = 'MyDatabase')
DROP DATABASE MyDatabase;
GO
-- Create the MyDatabase database.
CREATE DATABASE MyDatabase COLLATE SQL_Latin1_General_CP1_CI_AS;
GO
-- Specify a simple recovery model
-- to keep the log growth to a minimum.
ALTER DATABASE MyDatabase
SET RECOVERY SIMPLE;
GO
USE MyDatabase;
GO
CREATE TABLE [dbo].[Course] (
[CourseID] INT NOT NULL,
[CourseName] NVARCHAR (50) NOT NULL,
PRIMARY KEY CLUSTERED ([CourseID] ASC)
);
CREATE TABLE [dbo].[Student] (
[StudentID] INT NOT NULL,
[Name] NVARCHAR (50) NOT NULL,
[Age] INT NULL,
PRIMARY KEY CLUSTERED ([StudentID] ASC)
);
CREATE TABLE [dbo].[CourseSelection] (
[ID] INT NOT NULL,
[StudentID] INT NOT NULL,
[CourseID] INT NOT NULL,
PRIMARY KEY CLUSTERED ([ID] ASC),
CONSTRAINT [FK_CourseSelection_ToTable] FOREIGN KEY ([StudentID]) REFERENCES [dbo].[Student] ([StudentID]) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT [FK_CourseSelection_Course_1] FOREIGN KEY ([CourseID]) REFERENCES [dbo].[Course] ([CourseID]) ON DELETE NO ACTION ON UPDATE NO ACTION
);
CREATE TABLE [dbo].[LastStudent] (
[StudentID] INT NOT NULL,
[Name] NVARCHAR (50) NOT NULL,
[Age] INT NULL,
PRIMARY KEY CLUSTERED ([StudentID] ASC)
);
-- Insert data into the tables.
USE MyDatabase
INSERT INTO Course (CourseID, CourseName)
VALUES(1, 'Algebra I');
INSERT INTO Course (CourseID, CourseName)
VALUES(2, 'Trigonometry');
INSERT INTO Course (CourseID, CourseName)
VALUES(3, 'Algebra II');
INSERT INTO Course (CourseID, CourseName)
VALUES(4, 'History');
INSERT INTO Course (CourseID, CourseName)
VALUES(5, 'English');
INSERT INTO Course (CourseID, CourseName)
VALUES(6, 'French');
INSERT INTO Course (CourseID, CourseName)
VALUES(7, 'Chinese');
INSERT INTO Student (StudentID, Name, Age)
VALUES(1, 'Abercrombie, Kim', 10);
INSERT INTO Student (StudentID, Name, Age)
VALUES(2, 'Abolrous, Hazen', 14);
INSERT INTO Student (StudentID, Name, Age)
VALUES(3, 'Hance, Jim', 12);
INSERT INTO Student (StudentID, Name, Age)
VALUES(4, 'Adams, Terry', 12);
INSERT INTO Student (StudentID, Name, Age)
VALUES(5, 'Hansen, Claus', 11);
INSERT INTO Student (StudentID, Name, Age)
VALUES(6, 'Penor, Lori', 13);
INSERT INTO Student (StudentID, Name, Age)
VALUES(7, 'Perham, Tom', 12);
INSERT INTO Student (StudentID, Name, Age)
VALUES(8, 'Peng, Yun-Feng', NULL);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(1, 1, 2);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(2, 1, 3);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(3, 1, 5);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(4, 2, 2);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(5, 2, 5);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(6, 2, 6);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(7, 2, 3);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(8, 3, 2);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(9, 3, 1);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(10, 4, 2);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(11, 4, 5);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(12, 4, 2);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(13, 5, 3);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(14, 5, 2);
INSERT INTO CourseSelection (ID, StudentID, CourseID)
VALUES(15, 7, 3);
Poniższy kod zawiera przykładowy kod, który zostanie wyświetlony w tym temacie.
#if INTERACTIVE
#r "FSharp.Data.TypeProviders.dll"
#r "System.Data.dll"
#r "System.Data.Linq.dll"
#endif
open System
open Microsoft.FSharp.Data.TypeProviders
open System.Data.Linq.SqlClient
open System.Linq
type schema = SqlDataConnection<"Data Source=SERVER\INSTANCE;Initial Catalog=MyDatabase;Integrated Security=SSPI;">
let db = schema.GetDataContext()
let data = [1; 5; 7; 11; 18; 21]
type Nullable<'T when 'T : ( new : unit -> 'T) and 'T : struct and 'T :> ValueType > with
member this.Print() =
if this.HasValue then this.Value.ToString()
else "NULL"
printfn "\ncontains query operator"
query {
for student in db.Student do
select student.Age.Value
contains 11
}
|> printfn "Is at least one student age 11? %b"
printfn "\ncount query operator"
query {
for student in db.Student do
select student
count
}
|> printfn "Number of students: %d"
printfn "\nlast query operator."
let num =
query {
for number in data do
sortBy number
last
}
printfn "Last number: %d" num
open Microsoft.FSharp.Linq
printfn "\nlastOrDefault query operator."
query {
for number in data do
sortBy number
lastOrDefault
}
|> printfn "lastOrDefault: %d"
printfn "\nexactlyOne query operator."
let student2 =
query {
for student in db.Student do
where (student.StudentID = 1)
select student
exactlyOne
}
printfn "Student with StudentID = 1 is %s" student2.Name
printfn "\nexactlyOneOrDefault query operator."
let student3 =
query {
for student in db.Student do
where (student.StudentID = 1)
select student
exactlyOneOrDefault
}
printfn "Student with StudentID = 1 is %s" student3.Name
printfn "\nheadOrDefault query operator."
let student4 =
query {
for student in db.Student do
select student
headOrDefault
}
printfn "head student is %s" student4.Name
printfn "\nselect query operator."
query {
for student in db.Student do
select student
}
|> Seq.iter (fun student -> printfn "StudentID, Name: %d %s" student.StudentID student.Name)
printfn "\nwhere query operator."
query {
for student in db.Student do
where (student.StudentID > 4)
select student
}
|> Seq.iter (fun student -> printfn "StudentID, Name: %d %s" student.StudentID student.Name)
printfn "\nminBy query operator."
let student5 =
query {
for student in db.Student do
minBy student.StudentID
}
printfn "\nmaxBy query operator."
let student6 =
query {
for student in db.Student do
maxBy student.StudentID
}
printfn "\ngroupBy query operator."
query {
for student in db.Student do
groupBy student.Age into g
select (g.Key, g.Count())
}
|> Seq.iter (fun (age, count) -> printfn "Age: %s Count at that age: %d" (age.Print()) count)
printfn "\nsortBy query operator."
query {
for student in db.Student do
sortBy student.Name
select student
}
|> Seq.iter (fun student -> printfn "StudentID, Name: %d %s" student.StudentID student.Name)
printfn "\nsortByDescending query operator."
query {
for student in db.Student do
sortByDescending student.Name
select student
}
|> Seq.iter (fun student -> printfn "StudentID, Name: %d %s" student.StudentID student.Name)
printfn "\nthenBy query operator."
query {
for student in db.Student do
where student.Age.HasValue
sortBy student.Age.Value
thenBy student.Name
select student
}
|> Seq.iter (fun student -> printfn "StudentID, Name: %d %s" student.Age.Value student.Name)
printfn "\nthenByDescending query operator."
query {
for student in db.Student do
where student.Age.HasValue
sortBy student.Age.Value
thenByDescending student.Name
select student
}
|> Seq.iter (fun student -> printfn "StudentID, Name: %d %s" student.Age.Value student.Name)
printfn "\ngroupValBy query operator."
query {
for student in db.Student do
groupValBy student.Name student.Age into g
select (g, g.Key, g.Count())
}
|> Seq.iter (fun (group, age, count) ->
printfn "Age: %s Count at that age: %d" (age.Print()) count
group |> Seq.iter (fun name -> printfn "Name: %s" name))
printfn "\n sumByNullable query operator"
query {
for student in db.Student do
sumByNullable student.Age
}
|> (fun sum -> printfn "Sum of ages: %s" (sum.Print()))
printfn "\n minByNullable"
query {
for student in db.Student do
minByNullable student.Age
}
|> (fun age -> printfn "Minimum age: %s" (age.Print()))
printfn "\n maxByNullable"
query {
for student in db.Student do
maxByNullable student.Age
}
|> (fun age -> printfn "Maximum age: %s" (age.Print()))
printfn "\n averageBy"
query {
for student in db.Student do
averageBy (float student.StudentID)
}
|> printfn "Average student ID: %f"
printfn "\n averageByNullable"
query {
for student in db.Student do
averageByNullable (Nullable.float student.Age)
}
|> (fun avg -> printfn "Average age: %s" (avg.Print()))
printfn "\n find query operator"
query {
for student in db.Student do
find (student.Name = "Abercrombie, Kim")
}
|> (fun student -> printfn "Found a match with StudentID = %d" student.StudentID)
printfn "\n all query operator"
query {
for student in db.Student do
all (SqlMethods.Like(student.Name, "%,%"))
}
|> printfn "Do all students have a comma in the name? %b"
printfn "\n head query operator"
query {
for student in db.Student do
head
}
|> (fun student -> printfn "Found the head student with StudentID = %d" student.StudentID)
printfn "\n nth query operator"
query {
for numbers in data do
nth 3
}
|> printfn "Third number is %d"
printfn "\n skip query operator"
query {
for student in db.Student do
skip 1
}
|> Seq.iter (fun student -> printfn "StudentID = %d" student.StudentID)
printfn "\n skipWhile query operator"
query {
for number in data do
skipWhile (number < 3)
select number
}
|> Seq.iter (fun number -> printfn "Number = %d" number)
printfn "\n sumBy query operator"
query {
for student in db.Student do
sumBy student.StudentID
}
|> printfn "Sum of student IDs: %d"
printfn "\n take query operator"
query {
for student in db.Student do
select student
take 2
}
|> Seq.iter (fun student -> printfn "StudentID = %d" student.StudentID)
printfn "\n takeWhile query operator"
query {
for number in data do
takeWhile (number < 10)
}
|> Seq.iter (fun number -> printfn "Number = %d" number)
printfn "\n sortByNullable query operator"
query {
for student in db.Student do
sortByNullable student.Age
select student
}
|> Seq.iter (fun student ->
printfn "StudentID, Name, Age: %d %s %s" student.StudentID student.Name (student.Age.Print()))
printfn "\n sortByNullableDescending query operator"
query {
for student in db.Student do
sortByNullableDescending student.Age
select student
}
|> Seq.iter (fun student ->
printfn "StudentID, Name, Age: %d %s %s" student.StudentID student.Name (student.Age.Print()))
printfn "\n thenByNullable query operator"
query {
for student in db.Student do
sortBy student.Name
thenByNullable student.Age
select student
}
|> Seq.iter (fun student ->
printfn "StudentID, Name, Age: %d %s %s" student.StudentID student.Name (student.Age.Print()))
printfn "\n thenByNullableDescending query operator"
query {
for student in db.Student do
sortBy student.Name
thenByNullableDescending student.Age
select student
}
|> Seq.iter (fun student ->
printfn "StudentID, Name, Age: %d %s %s" student.StudentID student.Name (student.Age.Print()))
printfn "All students: "
query {
for student in db.Student do
select student
}
|> Seq.iter (fun student -> printfn "%s %d %s" student.Name student.StudentID (student.Age.Print()))
printfn "\nCount of students: "
query {
for student in db.Student do
count
}
|> (fun count -> printfn "Student count: %d" count)
printfn "\nExists."
query {
for student in db.Student do
where
(query {
for courseSelection in db.CourseSelection do
exists (courseSelection.StudentID = student.StudentID) })
select student
}
|> Seq.iter (fun student -> printfn "%A" student.Name)
printfn "\n Group by age and count"
query {
for n in db.Student do
groupBy n.Age into g
select (g.Key, g.Count())
}
|> Seq.iter (fun (age, count) -> printfn "%s %d" (age.Print()) count)
printfn "\n Group value by age."
query {
for n in db.Student do
groupValBy n.Age n.Age into g
select (g.Key, g.Count())
}
|> Seq.iter (fun (age, count) -> printfn "%s %d" (age.Print()) count)
printfn "\nGroup students by age where age > 10."
query {
for student in db.Student do
groupBy student.Age into g
where (g.Key.HasValue && g.Key.Value > 10)
select (g, g.Key)
}
|> Seq.iter (fun (students, age) ->
printfn "Age: %s" (age.Value.ToString())
students
|> Seq.iter (fun student -> printfn "%s" student.Name))
printfn "\nGroup students by age and print counts of number of students at each age with more than 1 student."
query {
for student in db.Student do
groupBy student.Age into group
where (group.Count() > 1)
select (group.Key, group.Count())
}
|> Seq.iter (fun (age, ageCount) ->
printfn "Age: %s Count: %d" (age.Print()) ageCount)
printfn "\nGroup students by age and sum ages."
query {
for student in db.Student do
groupBy student.Age into g
let total = query { for student in g do sumByNullable student.Age }
select (g.Key, g.Count(), total)
}
|> Seq.iter (fun (age, count, total) ->
printfn "Age: %d" (age.GetValueOrDefault())
printfn "Count: %d" count
printfn "Total years: %s" (total.ToString()))
printfn "\nGroup students by age and count number of students at each age, and display all with count > 1 in descending order of count."
query {
for student in db.Student do
groupBy student.Age into g
where (g.Count() > 1)
sortByDescending (g.Count())
select (g.Key, g.Count())
}
|> Seq.iter (fun (age, myCount) ->
printfn "Age: %s" (age.Print())
printfn "Count: %d" myCount)
printfn "\n Select students from a set of IDs"
let idList = [1; 2; 5; 10]
let idQuery =
query { for id in idList do select id }
query {
for student in db.Student do
where (idQuery.Contains(student.StudentID))
select student
}
|> Seq.iter (fun student ->
printfn "Name: %s" student.Name)
printfn "\nLook for students with Name match _e%% pattern and take first two."
query {
for student in db.Student do
where (SqlMethods.Like( student.Name, "_e%") )
select student
take 2
}
|> Seq.iter (fun student -> printfn "%s" student.Name)
printfn "\nLook for students with Name matching [abc]%% pattern."
query {
for student in db.Student do
where (SqlMethods.Like( student.Name, "[abc]%") )
select student
}
|> Seq.iter (fun student -> printfn "%s" student.Name)
printfn "\nLook for students with name matching [^abc]%% pattern."
query {
for student in db.Student do
where (SqlMethods.Like( student.Name, "[^abc]%") )
select student
}
|> Seq.iter (fun student -> printfn "%s" student.Name)
printfn "\nLook for students with name matching [^abc]%% pattern and select ID."
query {
for n in db.Student do
where (SqlMethods.Like( n.Name, "[^abc]%") )
select n.StudentID
}
|> Seq.iter (fun id -> printfn "%d" id)
printfn "\n Using Contains as a query filter."
query {
for student in db.Student do
where (student.Name.Contains("a"))
select student
}
|> Seq.iter (fun student -> printfn "%s" student.Name)
printfn "\nSearching for names from a list."
let names = [|"a";"b";"c"|]
query {
for student in db.Student do
if names.Contains (student.Name) then select student
}
|> Seq.iter (fun student -> printfn "%s" student.Name)
printfn "\nJoin Student and CourseSelection tables."
query {
for student in db.Student do
join selection in db.CourseSelection
on (student.StudentID = selection.StudentID)
select (student, selection)
}
|> Seq.iter (fun (student, selection) -> printfn "%d %s %d" student.StudentID student.Name selection.CourseID)
printfn "\nLeft Join Student and CourseSelection tables."
query {
for student in db.Student do
leftOuterJoin selection in db.CourseSelection
on (student.StudentID = selection.StudentID) into result
for selection in result.DefaultIfEmpty() do
select (student, selection)
}
|> Seq.iter (fun (student, selection) ->
let selectionID, studentID, courseID =
match selection with
| null -> "NULL", "NULL", "NULL"
| sel -> (sel.ID.ToString(), sel.StudentID.ToString(), sel.CourseID.ToString())
printfn "%d %s %d %s %s %s" student.StudentID student.Name (student.Age.GetValueOrDefault()) selectionID studentID courseID)
printfn "\nJoin with count"
query {
for n in db.Student do
join e in db.CourseSelection
on (n.StudentID = e.StudentID)
count
}
|> printfn "%d"
printfn "\n Join with distinct."
query {
for student in db.Student do
join selection in db.CourseSelection
on (student.StudentID = selection.StudentID)
distinct
}
|> Seq.iter (fun (student, selection) -> printfn "%s %d" student.Name selection.CourseID)
printfn "\n Join with distinct and count."
query {
for n in db.Student do
join e in db.CourseSelection
on (n.StudentID = e.StudentID)
distinct
count
}
|> printfn "%d"
printfn "\n Selecting students with age between 10 and 15."
query {
for student in db.Student do
where (student.Age.Value >= 10 && student.Age.Value < 15)
select student
}
|> Seq.iter (fun student -> printfn "%s" student.Name)
printfn "\n Selecting students with age either 11 or 12."
query {
for student in db.Student do
where (student.Age.Value = 11 || student.Age.Value = 12)
select student
}
|> Seq.iter (fun student -> printfn "%s" student.Name)
printfn "\n Selecting students in a certain age range and sorting."
query {
for n in db.Student do
where (n.Age.Value = 12 || n.Age.Value = 13)
sortByNullableDescending n.Age
select n
}
|> Seq.iter (fun student -> printfn "%s %s" student.Name (student.Age.Print()))
printfn "\n Selecting students with certain ages, taking account of possibility of nulls."
query {
for student in db.Student do
where
((student.Age.HasValue && student.Age.Value = 11) ||
(student.Age.HasValue && student.Age.Value = 12))
sortByDescending student.Name
select student.Name
take 2
}
|> Seq.iter (fun name -> printfn "%s" name)
printfn "\n Union of two queries."
module Queries =
let query1 = query {
for n in db.Student do
select (n.Name, n.Age)
}
let query2 = query {
for n in db.LastStudent do
select (n.Name, n.Age)
}
query2.Union (query1)
|> Seq.iter (fun (name, age) -> printfn "%s %s" name (age.Print()))
printfn "\n Intersect of two queries."
module Queries2 =
let query1 = query {
for n in db.Student do
select (n.Name, n.Age)
}
let query2 = query {
for n in db.LastStudent do
select (n.Name, n.Age)
}
query1.Intersect(query2)
|> Seq.iter (fun (name, age) -> printfn "%s %s" name (age.Print()))
printfn "\n Using if statement to alter results for special value."
query {
for student in db.Student do
select
(if student.Age.HasValue && student.Age.Value = -1 then
(student.StudentID, System.Nullable<int>(100), student.Age)
else (student.StudentID, student.Age, student.Age))
}
|> Seq.iter (fun (id, value, age) -> printfn "%d %s %s" id (value.Print()) (age.Print()))
printfn "\n Using if statement to alter results special values."
query {
for student in db.Student do
select
(if student.Age.HasValue && student.Age.Value = -1 then
(student.StudentID, System.Nullable<int>(100), student.Age)
elif student.Age.HasValue && student.Age.Value = 0 then
(student.StudentID, System.Nullable<int>(100), student.Age)
else (student.StudentID, student.Age, student.Age))
}
|> Seq.iter (fun (id, value, age) -> printfn "%d %s %s" id (value.Print()) (age.Print()))
printfn "\n Multiple table select."
query {
for student in db.Student do
for course in db.Course do
select (student, course)
}
|> Seq.iteri (fun index (student, course) ->
if index = 0 then
printfn "StudentID Name Age CourseID CourseName"
printfn "%d %s %s %d %s" student.StudentID student.Name (student.Age.Print()) course.CourseID course.CourseName)
printfn "\nMultiple Joins"
query {
for student in db.Student do
join courseSelection in db.CourseSelection
on (student.StudentID = courseSelection.StudentID)
join course in db.Course
on (courseSelection.CourseID = course.CourseID)
select (student.Name, course.CourseName)
}
|> Seq.iter (fun (studentName, courseName) -> printfn "%s %s" studentName courseName)
printfn "\nMultiple Left Outer Joins"
query {
for student in db.Student do
leftOuterJoin courseSelection in db.CourseSelection
on (student.StudentID = courseSelection.StudentID) into g1
for courseSelection in g1.DefaultIfEmpty() do
leftOuterJoin course in db.Course
on (courseSelection.CourseID = course.CourseID) into g2
for course in g2.DefaultIfEmpty() do
select (student.Name, course.CourseName)
}
|> Seq.iter (fun (studentName, courseName) -> printfn "%s %s" studentName courseName)
Oto pełne dane wyjściowe, gdy ten kod jest uruchamiany w języku F# Interactive.
--> Referenced 'C:\Program Files (x86)\Reference Assemblies\Microsoft\FSharp\3.0\Runtime\v4.0\Type Providers\FSharp.Data.TypeProviders.dll'
--> Referenced 'C:\Windows\Microsoft.NET\Framework\v4.0.30319\System.Data.dll'
--> Referenced 'C:\Windows\Microsoft.NET\Framework\v4.0.30319\System.Data.Linq.dll'
contains query operator
Binding session to 'C:\Users\ghogen\AppData\Local\Temp\tmp5E3C.dll'...
Binding session to 'C:\Users\ghogen\AppData\Local\Temp\tmp611A.dll'...
Is at least one student age 11? true
count query operator
Number of students: 8
last query operator.
Last number: 21
lastOrDefault query operator.
lastOrDefault: 21
exactlyOne query operator.
Student with StudentID = 1 is Abercrombie, Kim
exactlyOneOrDefault query operator.
Student with StudentID = 1 is Abercrombie, Kim
headOrDefault query operator.
head student is Abercrombie, Kim
select query operator.
StudentID, Name: 1 Abercrombie, Kim
StudentID, Name: 2 Abolrous, Hazen
StudentID, Name: 3 Hance, Jim
StudentID, Name: 4 Adams, Terry
StudentID, Name: 5 Hansen, Claus
StudentID, Name: 6 Penor, Lori
StudentID, Name: 7 Perham, Tom
StudentID, Name: 8 Peng, Yun-Feng
where query operator.
StudentID, Name: 5 Hansen, Claus
StudentID, Name: 6 Penor, Lori
StudentID, Name: 7 Perham, Tom
StudentID, Name: 8 Peng, Yun-Feng
minBy query operator.
maxBy query operator.
groupBy query operator.
Age: NULL Count at that age: 1
Age: 10 Count at that age: 1
Age: 11 Count at that age: 1
Age: 12 Count at that age: 3
Age: 13 Count at that age: 1
Age: 14 Count at that age: 1
sortBy query operator.
StudentID, Name: 1 Abercrombie, Kim
StudentID, Name: 2 Abolrous, Hazen
StudentID, Name: 4 Adams, Terry
StudentID, Name: 3 Hance, Jim
StudentID, Name: 5 Hansen, Claus
StudentID, Name: 8 Peng, Yun-Feng
StudentID, Name: 6 Penor, Lori
StudentID, Name: 7 Perham, Tom
sortByDescending query operator.
StudentID, Name: 7 Perham, Tom
StudentID, Name: 6 Penor, Lori
StudentID, Name: 8 Peng, Yun-Feng
StudentID, Name: 5 Hansen, Claus
StudentID, Name: 3 Hance, Jim
StudentID, Name: 4 Adams, Terry
StudentID, Name: 2 Abolrous, Hazen
StudentID, Name: 1 Abercrombie, Kim
thenBy query operator.
StudentID, Name: 10 Abercrombie, Kim
StudentID, Name: 11 Hansen, Claus
StudentID, Name: 12 Adams, Terry
StudentID, Name: 12 Hance, Jim
StudentID, Name: 12 Perham, Tom
StudentID, Name: 13 Penor, Lori
StudentID, Name: 14 Abolrous, Hazen
thenByDescending query operator.
StudentID, Name: 10 Abercrombie, Kim
StudentID, Name: 11 Hansen, Claus
StudentID, Name: 12 Perham, Tom
StudentID, Name: 12 Hance, Jim
StudentID, Name: 12 Adams, Terry
StudentID, Name: 13 Penor, Lori
StudentID, Name: 14 Abolrous, Hazen
groupValBy query operator.
Age: NULL Count at that age: 1
Name: Peng, Yun-Feng
Age: 10 Count at that age: 1
Name: Abercrombie, Kim
Age: 11 Count at that age: 1
Name: Hansen, Claus
Age: 12 Count at that age: 3
Name: Hance, Jim
Name: Adams, Terry
Name: Perham, Tom
Age: 13 Count at that age: 1
Name: Penor, Lori
Age: 14 Count at that age: 1
Name: Abolrous, Hazen
sumByNullable query operator
Sum of ages: 84
minByNullable
Minimum age: 10
maxByNullable
Maximum age: 14
averageBy
Average student ID: 4.500000
averageByNullable
Average age: 12
find query operator
Found a match with StudentID = 1
all query operator
Do all students have a comma in the name? true
head query operator
Found the head student with StudentID = 1
nth query operator
Third number is 11
skip query operator
StudentID = 2
StudentID = 3
StudentID = 4
StudentID = 5
StudentID = 6
StudentID = 7
StudentID = 8
skipWhile query operator
Number = 5
Number = 7
Number = 11
Number = 18
Number = 21
sumBy query operator
Sum of student IDs: 36
take query operator
StudentID = 1
StudentID = 2
takeWhile query operator
Number = 1
Number = 5
Number = 7
sortByNullable query operator
StudentID, Name, Age: 8 Peng, Yun-Feng NULL
StudentID, Name, Age: 1 Abercrombie, Kim 10
StudentID, Name, Age: 5 Hansen, Claus 11
StudentID, Name, Age: 7 Perham, Tom 12
StudentID, Name, Age: 3 Hance, Jim 12
StudentID, Name, Age: 4 Adams, Terry 12
StudentID, Name, Age: 6 Penor, Lori 13
StudentID, Name, Age: 2 Abolrous, Hazen 14
sortByNullableDescending query operator
StudentID, Name, Age: 2 Abolrous, Hazen 14
StudentID, Name, Age: 6 Penor, Lori 13
StudentID, Name, Age: 7 Perham, Tom 12
StudentID, Name, Age: 3 Hance, Jim 12
StudentID, Name, Age: 4 Adams, Terry 12
StudentID, Name, Age: 5 Hansen, Claus 11
StudentID, Name, Age: 1 Abercrombie, Kim 10
StudentID, Name, Age: 8 Peng, Yun-Feng NULL
thenByNullable query operator
StudentID, Name, Age: 1 Abercrombie, Kim 10
StudentID, Name, Age: 2 Abolrous, Hazen 14
StudentID, Name, Age: 4 Adams, Terry 12
StudentID, Name, Age: 3 Hance, Jim 12
StudentID, Name, Age: 5 Hansen, Claus 11
StudentID, Name, Age: 8 Peng, Yun-Feng NULL
StudentID, Name, Age: 6 Penor, Lori 13
StudentID, Name, Age: 7 Perham, Tom 12
thenByNullableDescending query operator
StudentID, Name, Age: 1 Abercrombie, Kim 10
StudentID, Name, Age: 2 Abolrous, Hazen 14
StudentID, Name, Age: 4 Adams, Terry 12
StudentID, Name, Age: 3 Hance, Jim 12
StudentID, Name, Age: 5 Hansen, Claus 11
StudentID, Name, Age: 8 Peng, Yun-Feng NULL
StudentID, Name, Age: 6 Penor, Lori 13
StudentID, Name, Age: 7 Perham, Tom 12
All students:
Abercrombie, Kim 1 10
Abolrous, Hazen 2 14
Hance, Jim 3 12
Adams, Terry 4 12
Hansen, Claus 5 11
Penor, Lori 6 13
Perham, Tom 7 12
Peng, Yun-Feng 8 NULL
Count of students:
Student count: 8
Exists.
"Abercrombie, Kim"
"Abolrous, Hazen"
"Hance, Jim"
"Adams, Terry"
"Hansen, Claus"
"Perham, Tom"
Group by age and count
NULL 1
10 1
11 1
12 3
13 1
14 1
Group value by age.
NULL 1
10 1
11 1
12 3
13 1
14 1
Group students by age where age > 10.
Age: 11
Hansen, Claus
Age: 12
Hance, Jim
Adams, Terry
Perham, Tom
Age: 13
Penor, Lori
Age: 14
Abolrous, Hazen
Group students by age and print counts of number of students at each age with more than 1 student.
Age: 12 Count: 3
Group students by age and sum ages.
Age: 0
Count: 1
Total years:
Age: 10
Count: 1
Total years: 10
Age: 11
Count: 1
Total years: 11
Age: 12
Count: 3
Total years: 36
Age: 13
Count: 1
Total years: 13
Age: 14
Count: 1
Total years: 14
Group students by age and count number of students at each age, and display all with count > 1 in descending order of count.
Age: 12
Count: 3
Select students from a set of IDs
Name: Abercrombie, Kim
Name: Abolrous, Hazen
Name: Hansen, Claus
Look for students with Name match _e% pattern and take first two.
Penor, Lori
Perham, Tom
Look for students with Name matching [abc]% pattern.
Abercrombie, Kim
Abolrous, Hazen
Adams, Terry
Look for students with name matching [^abc]% pattern.
Hance, Jim
Hansen, Claus
Penor, Lori
Perham, Tom
Peng, Yun-Feng
Look for students with name matching [^abc]% pattern and select ID.
3
5
6
7
8
Using Contains as a query filter.
Abercrombie, Kim
Abolrous, Hazen
Hance, Jim
Adams, Terry
Hansen, Claus
Perham, Tom
Searching for names from a list.
Join Student and CourseSelection tables.
2 Abolrous, Hazen 2
3 Hance, Jim 3
5 Hansen, Claus 5
2 Abolrous, Hazen 2
5 Hansen, Claus 5
6 Penor, Lori 6
3 Hance, Jim 3
2 Abolrous, Hazen 2
1 Abercrombie, Kim 1
2 Abolrous, Hazen 2
5 Hansen, Claus 5
2 Abolrous, Hazen 2
3 Hance, Jim 3
2 Abolrous, Hazen 2
3 Hance, Jim 3
Left Join Student and CourseSelection tables.
1 Abercrombie, Kim 10 9 3 1
2 Abolrous, Hazen 14 1 1 2
2 Abolrous, Hazen 14 4 2 2
2 Abolrous, Hazen 14 8 3 2
2 Abolrous, Hazen 14 10 4 2
2 Abolrous, Hazen 14 12 4 2
2 Abolrous, Hazen 14 14 5 2
3 Hance, Jim 12 2 1 3
3 Hance, Jim 12 7 2 3
3 Hance, Jim 12 13 5 3
3 Hance, Jim 12 15 7 3
4 Adams, Terry 12 NULL NULL NULL
5 Hansen, Claus 11 3 1 5
5 Hansen, Claus 11 5 2 5
5 Hansen, Claus 11 11 4 5
6 Penor, Lori 13 6 2 6
7 Perham, Tom 12 NULL NULL NULL
8 Peng, Yun-Feng 0 NULL NULL NULL
Join with count
15
Join with distinct.
Abercrombie, Kim 2
Abercrombie, Kim 3
Abercrombie, Kim 5
Abolrous, Hazen 2
Abolrous, Hazen 5
Abolrous, Hazen 6
Abolrous, Hazen 3
Hance, Jim 2
Hance, Jim 1
Adams, Terry 2
Adams, Terry 5
Adams, Terry 2
Hansen, Claus 3
Hansen, Claus 2
Perham, Tom 3
Join with distinct and count.
15
Selecting students with age between 10 and 15.
Abercrombie, Kim
Abolrous, Hazen
Hance, Jim
Adams, Terry
Hansen, Claus
Penor, Lori
Perham, Tom
Selecting students with age either 11 or 12.
Hance, Jim
Adams, Terry
Hansen, Claus
Perham, Tom
Selecting students in a certain age range and sorting.
Penor, Lori 13
Perham, Tom 12
Hance, Jim 12
Adams, Terry 12
Selecting students with certain ages, taking account of possibility of nulls.
Hance, Jim
Adams, Terry
Union of two queries.
Abercrombie, Kim 10
Abolrous, Hazen 14
Hance, Jim 12
Adams, Terry 12
Hansen, Claus 11
Penor, Lori 13
Perham, Tom 12
Peng, Yun-Feng NULL
Intersect of two queries.
Using if statement to alter results for special value.
1 10 10
2 14 14
3 12 12
4 12 12
5 11 11
6 13 13
7 12 12
8 NULL NULL
Using if statement to alter results special values.
1 10 10
2 14 14
3 12 12
4 12 12
5 11 11
6 13 13
7 12 12
8 NULL NULL
Multiple table select.
StudentID Name Age CourseID CourseName
1 Abercrombie, Kim 10 1 Algebra I
2 Abolrous, Hazen 14 1 Algebra I
3 Hance, Jim 12 1 Algebra I
4 Adams, Terry 12 1 Algebra I
5 Hansen, Claus 11 1 Algebra I
6 Penor, Lori 13 1 Algebra I
7 Perham, Tom 12 1 Algebra I
8 Peng, Yun-Feng NULL 1 Algebra I
1 Abercrombie, Kim 10 2 Trigonometry
2 Abolrous, Hazen 14 2 Trigonometry
3 Hance, Jim 12 2 Trigonometry
4 Adams, Terry 12 2 Trigonometry
5 Hansen, Claus 11 2 Trigonometry
6 Penor, Lori 13 2 Trigonometry
7 Perham, Tom 12 2 Trigonometry
8 Peng, Yun-Feng NULL 2 Trigonometry
1 Abercrombie, Kim 10 3 Algebra II
2 Abolrous, Hazen 14 3 Algebra II
3 Hance, Jim 12 3 Algebra II
4 Adams, Terry 12 3 Algebra II
5 Hansen, Claus 11 3 Algebra II
6 Penor, Lori 13 3 Algebra II
7 Perham, Tom 12 3 Algebra II
8 Peng, Yun-Feng NULL 3 Algebra II
1 Abercrombie, Kim 10 4 History
2 Abolrous, Hazen 14 4 History
3 Hance, Jim 12 4 History
4 Adams, Terry 12 4 History
5 Hansen, Claus 11 4 History
6 Penor, Lori 13 4 History
7 Perham, Tom 12 4 History
8 Peng, Yun-Feng NULL 4 History
1 Abercrombie, Kim 10 5 English
2 Abolrous, Hazen 14 5 English
3 Hance, Jim 12 5 English
4 Adams, Terry 12 5 English
5 Hansen, Claus 11 5 English
6 Penor, Lori 13 5 English
7 Perham, Tom 12 5 English
8 Peng, Yun-Feng NULL 5 English
1 Abercrombie, Kim 10 6 French
2 Abolrous, Hazen 14 6 French
3 Hance, Jim 12 6 French
4 Adams, Terry 12 6 French
5 Hansen, Claus 11 6 French
6 Penor, Lori 13 6 French
7 Perham, Tom 12 6 French
8 Peng, Yun-Feng NULL 6 French
1 Abercrombie, Kim 10 7 Chinese
2 Abolrous, Hazen 14 7 Chinese
3 Hance, Jim 12 7 Chinese
4 Adams, Terry 12 7 Chinese
5 Hansen, Claus 11 7 Chinese
6 Penor, Lori 13 7 Chinese
7 Perham, Tom 12 7 Chinese
8 Peng, Yun-Feng NULL 7 Chinese
Multiple Joins
Abercrombie, Kim Trigonometry
Abercrombie, Kim Algebra II
Abercrombie, Kim English
Abolrous, Hazen Trigonometry
Abolrous, Hazen English
Abolrous, Hazen French
Abolrous, Hazen Algebra II
Hance, Jim Trigonometry
Hance, Jim Algebra I
Adams, Terry Trigonometry
Adams, Terry English
Adams, Terry Trigonometry
Hansen, Claus Algebra II
Hansen, Claus Trigonometry
Perham, Tom Algebra II
Multiple Left Outer Joins
Abercrombie, Kim Trigonometry
Abercrombie, Kim Algebra II
Abercrombie, Kim English
Abolrous, Hazen Trigonometry
Abolrous, Hazen English
Abolrous, Hazen French
Abolrous, Hazen Algebra II
Hance, Jim Trigonometry
Hance, Jim Algebra I
Adams, Terry Trigonometry
Adams, Terry English
Adams, Terry Trigonometry
Hansen, Claus Algebra II
Hansen, Claus Trigonometry
Penor, Lori
Perham, Tom Algebra II
Peng, Yun-Feng
type schema
val db : schema.ServiceTypes.SimpleDataContextTypes.MyDatabase1
val student : System.Data.Linq.Table<schema.ServiceTypes.Student>
val data : int list = [1; 5; 7; 11; 18; 21]
type Nullable<'T
when 'T : (new : unit -> 'T) and 'T : struct and
'T :> System.ValueType> with
member Print : unit -> string
val num : int = 21
val student2 : schema.ServiceTypes.Student
val student3 : schema.ServiceTypes.Student
val student4 : schema.ServiceTypes.Student
val student5 : int = 1
val student6 : int = 8
val idList : int list = [1; 2; 5; 10]
val idQuery : seq<int>
val names : string [] = [|"a"; "b"; "c"|]
module Queries = begin
val query1 : System.Linq.IQueryable<string * System.Nullable<int>>
val query2 : System.Linq.IQueryable<string * System.Nullable<int>>
end
module Queries2 = begin
val query1 : System.Linq.IQueryable<string * System.Nullable<int>>
val query2 : System.Linq.IQueryable<string * System.Nullable<int>>
end