Yöntem Tabanlı Sorgu Söz Dizimi Örnekleri: İşleçleri Ayarlama (LINQ to DataSet)
Bu konudaki örneklerde, veri satırı kümelerinde değer tabanlı karşılaştırma işlemleri gerçekleştirmek için , Except, Intersectve Union işleçlerinin nasıl kullanılacağı Distinctgösterilmektedir.DataSet'e Veri Yükleme hakkında DataRowComparerdaha fazla bilgi için bkz. DataRows Karşılaştırma.
FillDataSet Bu örneklerde kullanılan yöntem, DataSet'e Veri Yükleme bölümünde belirtilmiştir.
Bu konudaki örneklerde AdventureWorks örnek veritabanındaki Contact, Address, Product, SalesOrderHeader ve SalesOrderDetail tabloları kullanılmıştır.
Bu konudaki örneklerde aşağıdaki using/Imports deyimler kullanılır:
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Globalization;
using System.Linq;
using System.Windows.Forms;
Option Explicit On
Imports System.Linq
Imports System.Linq.Expressions
Imports System.Collections.Generic
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.Common
Imports System.Globalization
Daha fazla bilgi için bkz . Nasıl yapılır: Visual Studio'da LINQ to DataSet Projesi Oluşturma.
Distinct
Örnek
Bu örnek, bir dizideki Distinct yinelenen öğeleri kaldırmak için yöntemini kullanır.
// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);
List<DataRow> rows = new List<DataRow>();
DataTable contact = ds.Tables["Contact"];
// Get 100 rows from the Contact table.
IEnumerable<DataRow> query = (from c in contact.AsEnumerable()
select c).Take(100);
DataTable contactsTableWith100Rows = query.CopyToDataTable();
// Add 100 rows to the list.
foreach (DataRow row in contactsTableWith100Rows.Rows)
rows.Add(row);
// Create duplicate rows by adding the same 100 rows to the list.
foreach (DataRow row in contactsTableWith100Rows.Rows)
rows.Add(row);
DataTable table =
System.Data.DataTableExtensions.CopyToDataTable<DataRow>(rows);
// Find the unique contacts in the table.
IEnumerable<DataRow> uniqueContacts =
table.AsEnumerable().Distinct(DataRowComparer.Default);
Console.WriteLine("Unique contacts:");
foreach (DataRow uniqueContact in uniqueContacts)
{
Console.WriteLine(uniqueContact.Field<Int32>("ContactID"));
}
' Fill the DataSet.
Dim ds As New DataSet()
ds.Locale = CultureInfo.InvariantCulture
' See the FillDataSet method in the Loading Data Into a DataSet topic.
FillDataSet(ds)
Dim rows As List(Of DataRow) = New List(Of DataRow)
Dim contacts As DataTable = ds.Tables("Contact")
' Get 100 rows from the Contact table.
Dim query = ( _
From c In contacts.AsEnumerable() _
Select c).Take(100)
Dim contactsTableWith100Rows = query.CopyToDataTable()
' Add 100 rows to the list.
For Each row In contactsTableWith100Rows.Rows
rows.Add(row)
Next
' Create duplicate rows by adding the same 100 rows to the list.
For Each row In contactsTableWith100Rows.Rows
rows.Add(row)
Next
Dim table = _
System.Data.DataTableExtensions.CopyToDataTable(Of DataRow)(rows)
' Find the unique contacts in the table.
Dim uniqueContacts = _
table.AsEnumerable().Distinct(DataRowComparer.Default)
Console.WriteLine("Unique contacts:")
For Each uniqueContact In uniqueContacts
Console.WriteLine(uniqueContact.Field(Of Integer)("ContactID"))
Next
Dışlama
Örnek
Bu örnek, Except birinci tabloda görünen ancak ikinci tabloda görünmeyen kişileri döndürmek için yöntemini kullanır.
// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);
DataTable contactTable = ds.Tables["Contact"];
// Create two tables.
IEnumerable<DataRow> query1 = from contact in contactTable.AsEnumerable()
where contact.Field<string>("Title") == "Ms."
select contact;
IEnumerable<DataRow> query2 = from contact in contactTable.AsEnumerable()
where contact.Field<string>("FirstName") == "Sandra"
select contact;
DataTable contacts1 = query1.CopyToDataTable();
DataTable contacts2 = query2.CopyToDataTable();
// Find the contacts that are in the first
// table but not the second.
var contacts = contacts1.AsEnumerable().Except(contacts2.AsEnumerable(),
DataRowComparer.Default);
Console.WriteLine("Except of employees tables");
foreach (DataRow row in contacts)
{
Console.WriteLine("Id: {0} {1} {2} {3}",
row["ContactID"], row["Title"], row["FirstName"], row["LastName"]);
}
' Fill the DataSet.
Dim ds As New DataSet()
ds.Locale = CultureInfo.InvariantCulture
' See the FillDataSet method in the Loading Data Into a DataSet topic.
FillDataSet(ds)
Dim contactTable As DataTable = ds.Tables("Contact")
Dim query1 = _
From contact In contactTable.AsEnumerable() _
Where contact.Field(Of String)("Title") = "Ms." _
Select contact
Dim query2 = _
From contact In contactTable.AsEnumerable() _
Where contact.Field(Of String)("FirstName") = "Sandra" _
Select contact
Dim contacts1 = query1.CopyToDataTable()
Dim contacts2 = query2.CopyToDataTable()
' Find the contacts that are in the first
' table but not the second.
Dim contacts = contacts1.AsEnumerable().Except(contacts2.AsEnumerable(), _
DataRowComparer.Default)
Console.WriteLine("Except of employees tables")
For Each row In contacts
Console.WriteLine("Id: {0} {1} {2} {3}", _
row("ContactID"), row("Title"), row("FirstName"), row("LastName"))
Next
Kesiştir
Örnek
Bu örnek, Intersect her iki tabloda da görünen kişileri döndürmek için yöntemini kullanır.
// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);
DataTable contactTable = ds.Tables["Contact"];
// Create two tables.
IEnumerable<DataRow> query1 = from contact in contactTable.AsEnumerable()
where contact.Field<string>("Title") == "Ms."
select contact;
IEnumerable<DataRow> query2 = from contact in contactTable.AsEnumerable()
where contact.Field<string>("FirstName") == "Sandra"
select contact;
DataTable contacts1 = query1.CopyToDataTable();
DataTable contacts2 = query2.CopyToDataTable();
// Find the intersection of the two tables.
var contacts = contacts1.AsEnumerable().Intersect(contacts2.AsEnumerable(),
DataRowComparer.Default);
Console.WriteLine("Intersection of contacts tables");
foreach (DataRow row in contacts)
{
Console.WriteLine("Id: {0} {1} {2} {3}",
row["ContactID"], row["Title"], row["FirstName"], row["LastName"]);
}
' Fill the DataSet.
Dim ds As New DataSet()
ds.Locale = CultureInfo.InvariantCulture
' See the FillDataSet method in the Loading Data Into a DataSet topic.
FillDataSet(ds)
Dim contactTable As DataTable = ds.Tables("Contact")
Dim query1 = _
From contact In contactTable.AsEnumerable() _
Where contact.Field(Of String)("Title") = "Ms." _
Select contact
Dim query2 = _
From contact In contactTable.AsEnumerable() _
Where contact.Field(Of String)("FirstName") = "Sandra" _
Select contact
Dim contacts1 = query1.CopyToDataTable()
Dim contacts2 = query2.CopyToDataTable()
Dim contacts = contacts1.AsEnumerable() _
.Intersect(contacts2.AsEnumerable(), DataRowComparer.Default)
Console.WriteLine("Intersect of employees tables")
For Each row In contacts
Console.WriteLine("Id: {0} {1} {2} {3}", _
row("ContactID"), row("Title"), row("FirstName"), row("LastName"))
Next
Birleşim
Örnek
Bu örnekte, iki tablodan Union herhangi birinden benzersiz kişiler döndürmek için yöntemi kullanılır.
// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);
// Create two tables.
DataTable contactTable = ds.Tables["Contact"];
IEnumerable<DataRow> query1 = from contact in contactTable.AsEnumerable()
where contact.Field<string>("Title") == "Ms."
select contact;
IEnumerable<DataRow> query2 = from contact in contactTable.AsEnumerable()
where contact.Field<string>("FirstName") == "Sandra"
select contact;
DataTable contacts1 = query1.CopyToDataTable();
DataTable contacts2 = query2.CopyToDataTable();
// Find the union of the two tables.
var contacts = contacts1.AsEnumerable().Union(contacts2.AsEnumerable(),
DataRowComparer.Default);
Console.WriteLine("Union of contacts tables:");
foreach (DataRow row in contacts)
{
Console.WriteLine("Id: {0} {1} {2} {3}",
row["ContactID"], row["Title"], row["FirstName"], row["LastName"]);
}
' Fill the DataSet.
Dim ds As New DataSet()
ds.Locale = CultureInfo.InvariantCulture
' See the FillDataSet method in the Loading Data Into a DataSet topic.
FillDataSet(ds)
Dim contactTable As DataTable = ds.Tables("Contact")
Dim query1 = _
From contact In contactTable.AsEnumerable() _
Where contact.Field(Of String)("Title") = "Ms." _
Select contact
Dim query2 = _
From contact In contactTable.AsEnumerable() _
Where contact.Field(Of String)("FirstName") = "Sandra" _
Select contact
Dim contacts1 = query1.CopyToDataTable()
Dim contacts2 = query2.CopyToDataTable()
Dim contacts = contacts1.AsEnumerable().Union(contacts2.AsEnumerable(), _
DataRowComparer.Default)
Console.WriteLine("Union of employees tables")
For Each row In contacts
Console.WriteLine("Id: {0} {1} {2} {3}", _
row("ContactID"), row("Title"), row("FirstName"), row("LastName"))
Next