Linq.rtf

7/27/2019 Linq.rtf

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EmployeeDesigner.cs

#pragma warning disable 1591

//------------------------------------------------------------------------------

// <auto-generated>// This code was generated by a tool.

// Runtime Version:4.0.30319.225

//

// Changes to this file may cause incorrect behavior and will be lost if

// the code is regenerated.

// </auto-generated>

//------------------------------------------------------------------------------

namespace LanguageEnhancements.DataAccess

{

using System.Data.Linq;

using System.Data.Linq.Mapping;

using System.Data;

using System.Collections.Generic;

using System.Reflection;

using System.Linq;

using System.Linq.Expressions;

using System.ComponentModel;

using System;

[global ::System.Data.Linq.Mapping. DatabaseAttribute (Name= "Employee" )]

public partial class EmployeeDataContext : System.Data.Linq. DataContext

{

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private static System.Data.Linq.Mapping. MappingSource mappingSource =new AttributeMappingSource ();

#region Extensibility Method Definitions

partial void OnCreated();

partial void InsertProduct( Product instance);

partial void UpdateProduct( Product instance);

partial void DeleteProduct( Product instance);

partial void InsertRegion( Region instance);

partial void UpdateRegion( Region instance);

partial void DeleteRegion( Region instance);

partial void InsertProductAvailability( ProductAvailability instance);

partial void UpdateProductAvailability( ProductAvailability instance);

partial void DeleteProductAvailability( ProductAvailability instance);

#endregion

public EmployeeDataContext() :

base (global ::LanguageEnhancements.Properties. Settings .Default.EmployeeConnectionString, mappingSource)

{

OnCreated();

}

public EmployeeDataContext( string connection) :

base (connection, mappingSource)

{

OnCreated();

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}

public EmployeeDataContext(System.Data. IDbConnection connection) :


{

OnCreated();

}

public EmployeeDataContext( string connection,System.Data.Linq.Mapping. MappingSource mappingSource) :


{

OnCreated();

}

public EmployeeDataContext(System.Data. IDbConnection connection,System.Data.Linq.Mapping. MappingSource mappingSource) :


{

OnCreated();

}

public System.Data.Linq. Table < Product > Products

{

get

{

return this .GetTable< Product >();

}

}

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public System.Data.Linq. Table < Region > Regions

{

get

{

return this .GetTable< Region >();

}

}

public System.Data.Linq. Table < ProductAvailability > ProductAvailabilities

{

get

{

return this .GetTable< ProductAvailability >();

}

}

}

[global ::System.Data.Linq.Mapping. TableAttribute (Name= "dbo.Products" )]

public partial class Product : INotifyPropertyChanging , INotifyPropertyChanged

{

private static PropertyChangingEventArgs emptyChangingEventArgs =new PropertyChangingEventArgs (String .Empty);

private int _ProductId;

private string _ProductName;

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private string _ProductDescription;

private int _ProductCount;

private EntityRef < ProductAvailability > _ProductAvailability;


partial void OnLoaded();

partial void OnValidate(System.Data.Linq. ChangeAction action);


partial void OnProductIdChanging( int value);

partial void OnProductIdChanged();

partial void OnProductNameChanging( string value);

partial void OnProductNameChanged();

partial void OnProductDescriptionChanging( string value);

partial void OnProductDescriptionChanged();

partial void OnProductCountChanging( int value);

partial void OnProductCountChanged();

#endregion

public Product()

{

this ._ProductAvailability = default (EntityRef < ProductAvailability >);

OnCreated();

}

[global ::System.Data.Linq.Mapping. ColumnAttribute (Storage= "_ProductId" ,DbType= "Int NOT NULL" , IsPrimaryKey= true )]

public int ProductId

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{

get

{

return this ._ProductId;

}

set

{

if (( this ._ProductId != value ))

{

this .OnProductIdChanging( value );

this .SendPropertyChanging();

this ._ProductId = value ;

this .SendPropertyChanged( "ProductId" );

this .OnProductIdChanged();

}

}

}

[global ::System.Data.Linq.Mapping. ColumnAttribute (Storage= "_ProductName" ,DbType= "NVarChar(50) NOT NULL" , CanBeNull= false )]

public string ProductName

{

get

{

return this ._ProductName;

}

set

{

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if (( this ._ProductName != value ))

{

this .OnProductNameChanging( value );


this ._ProductName = value ;

this .SendPropertyChanged( "ProductName" );

this .OnProductNameChanged();

}

}

}

[global ::System.Data.Linq.Mapping. ColumnAttribute (Storage= "_ProductDescription" ,DbType= "NVarChar(50) NOT NULL" , CanBeNull= false )]

public string ProductDescription

{

get

{

return this ._ProductDescription;

}

set

{

if (( this ._ProductDescription != value ))

{

this .OnProductDescriptionChanging( value );


this ._ProductDescription = value ;

this .SendPropertyChanged( "ProductDescription" );

this .OnProductDescriptionChanged();

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}

}

}

[global ::System.Data.Linq.Mapping. ColumnAttribute (Storage= "_ProductCount" ,DbType= "Int NOT NULL" )]

public int ProductCount

{

get

{

return this ._ProductCount;

}

set

{

if (( this ._ProductCount != value ))

{

this .OnProductCountChanging( value );


this ._ProductCount = value ;

this .SendPropertyChanged( "ProductCount" );

this .OnProductCountChanged();

}

}

}

[global ::System.Data.Linq.Mapping. AssociationAttribute (Name= "Product_ProductAvailability" , Storage= "_ProductAvailability" , ThisKey= "ProductId" , OtherKey= "ProductId" ,IsUnique= true , IsForeignKey= false )]

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public ProductAvailability ProductAvailability

{

get

{

return this ._ProductAvailability.Entity;

}

set

{

ProductAvailability previousValue =this ._ProductAvailability.Entity;

if (((previousValue != value )

||(this ._ProductAvailability.HasLoadedOrAssignedValue == false )))

{


if ((previousValue != null ))

{

this ._ProductAvailability.Entity = null ;

previousValue.Product = null ;

}

this ._ProductAvailability.Entity = value ;

if ((value != null ))

{

value .Product = this ;

}

this .SendPropertyChanged( "ProductAvailability" );

}

}

}

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public event PropertyChangingEventHandler PropertyChanging;

public event PropertyChangedEventHandler PropertyChanged;

protected virtual void SendPropertyChanging()

{

if (( this .PropertyChanging != null ))

{

this .PropertyChanging( this , emptyChangingEventArgs);

}

}

protected virtual void SendPropertyChanged( String propertyName)

{

if (( this .PropertyChanged != null ))

{

this .PropertyChanged( this , new PropertyChangedEventArgs (propertyName));

}

}

}

[global ::System.Data.Linq.Mapping. TableAttribute (Name= "dbo.Region" )]

public partial class Region : INotifyPropertyChanging , INotifyPropertyChanged

{


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private int _RegionId;

private string _RegionDescription;





partial void OnRegionIdChanging( int value);

partial void OnRegionIdChanged();

partial void OnRegionDescriptionChanging( string value);

partial void OnRegionDescriptionChanged();

#endregion

public Region()

{

OnCreated();

}

[global ::System.Data.Linq.Mapping. ColumnAttribute (Storage= "_RegionId" ,DbType= "Int NOT NULL" , IsPrimaryKey= true )]

public int RegionId

{

get

{

return this ._RegionId;

}

set

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{

if (( this ._RegionId != value ))

{

this .OnRegionIdChanging( value );


this ._RegionId = value ;

this .SendPropertyChanged( "RegionId" );

this .OnRegionIdChanged();

}

}

}

[global ::System.Data.Linq.Mapping. ColumnAttribute (Storage= "_RegionDescription" ,DbType= "NVarChar(50)" )]

public string RegionDescription

{

get

{

return this ._RegionDescription;

}

set

{

if (( this ._RegionDescription != value ))

{

this .OnRegionDescriptionChanging( value );


this ._RegionDescription = value ;

this .SendPropertyChanged( "RegionDescription" );

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this .OnRegionDescriptionChanged();

}

}

}




{


{


}

}


{


{


}

}

}

[global ::System.Data.Linq.Mapping. TableAttribute (Name= "dbo.ProductAvailability" )]

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public partial class ProductAvailability : INotifyPropertyChanging ,INotifyPropertyChanged

{


private int _ProductId;

private int _Status;

private EntityRef < Product > _Product;





partial void OnProductIdChanging( int value);

partial void OnProductIdChanged();

partial void OnStatusChanging( int value);

partial void OnStatusChanged();

#endregion

public ProductAvailability()

{

this ._Product = default (EntityRef < Product >);

OnCreated();

}

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[global ::System.Data.Linq.Mapping. ColumnAttribute (Storage= "_ProductId" ,DbType= "Int NOT NULL" , IsPrimaryKey= true )]

public int ProductId

{

get

{

return this ._ProductId;

}

set

{

if (( this ._ProductId != value ))

{

if (this ._Product.HasLoadedOrAssignedValue)

{

throw new System.Data.Linq. ForeignKeyReferenceAlreadyHasValueException ();

}

this .OnProductIdChanging( value );


this ._ProductId = value ;

this .SendPropertyChanged( "ProductId" );

this .OnProductIdChanged();

}

}

}

[global ::System.Data.Linq.Mapping. ColumnAttribute (Storage= "_Status" ,DbType= "Int NOT NULL" )]

public int Status

{

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get

{

return this ._Status;

}

set

{

if (( this ._Status != value ))

{

this .OnStatusChanging( value );


this ._Status = value ;

this .SendPropertyChanged( "Status" );

this .OnStatusChanged();

}

}

}

[global ::System.Data.Linq.Mapping. AssociationAttribute (Name= "Product_ProductAvailability" , Storage= "_Product" , ThisKey= "ProductId" , OtherKey= "ProductId" , IsForeignKey= true )]

public Product Product

{

get

{

return this ._Product.Entity;

}

set

{

Product previousValue = this ._Product.Entity;

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if (((previousValue != value )

||(this ._Product.HasLoadedOrAssignedValue == false )))

{


if ((previousValue != null ))

{

this ._Product.Entity = null ;

previousValue.ProductAvailability = null ;

}

this ._Product.Entity = value ;

if ((value != null ))

{

value .ProductAvailability = this ;

this ._ProductId = value .ProductId;

}

else

{this ._ProductId = default (int );

}

this .SendPropertyChanged( "Product" );

}

}

}



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{


{


}

}


{


{


}

}

}

}#pragma warning restore 1591

Program.cs

using System;


using System.Linq;

using System.Text;

using System.Xml.Linq;

using System.Data.Linq;

using LanguageEnhancements.DataAccess;

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namespace LanguageEnhancements

{

class Program

{

static void Main( string [] args)

{

// LinqToXml();

// LinqToObjects();

LinqToSql();

}

public static void LinqToObjects()

{ //uses System.Core.dll which is by default in the references

//Linq to Objects => datasource is in the form of objects.

string [] words = { "one" , "two" , "three" , "four" , "five" , "six" };

List < int > numbers = new List < int > { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

//LINQ Statement to extract words with less than or equal to 3 chars.

var shortWords = from word in words // words should balways be a collection andmust implement IEnumerable

where word.Length <= 3

select word; //Every LINQ statement must mandatorily have from andselect. where is optional

//LINQ Statement to extract words with less than or equal to 3 chars. Both this andthe above are same.

var otherWay = words.Where(w => w.Length <= 3).Select(w => w);

var evens = from num in numbers

where num % 2 == 0

orderby num descending

select num;

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//can also be written as follows

var evens1 = evens.Where(e => e % 2 == 0).Select(e => e);

numbers.Add(10); // the o/p will contain 10 also even though 10 is added tonumbers after the LINQ query.

// this is because the Linq query is not executed int the place where it is placed, itis only compiled.

// It will get executed only at foreach. A LINQ query will always be executed as lateas possible.

// If you want to execute it then and there then we can convert it into somecollection. ex:var evens = (from num in numbers

//where num % 2 == 0

//orderby num descending

// select num).ToArray();

foreach (var e in evens)

{

Console .WriteLine(e);

}

string [] colors = { "green" , "brown" , "blue" , "red" };

Console .WriteLine(colors.Max(c => c.Length)); //o/p is 5

//Console.WriteLine(colors.OrderBy(c=>c.Length).Single()); throws an exception

var query = colors.Where(c => c.Contains( "e" ));

query = query.Where(c => c.Contains( "n" ));

Console .WriteLine(query.Count()); // o/p is 1

}

public static void LinqToXml()

{

//we should include using System.Xml.Linq;

List < int > numbers = new List < int > { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

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XDocument doc = XDocument .Load( "NumberList.xml" ); // in the propertie of xmlfile set "copy to output directories" as "Copy always"

var shortWords = from word in doc.Descendants( "word" ) // this statement meansthat i want to explore all the decendents of the <word> tag

where word.Value.Length <= 3

select word.Value;

foreach (var e in shortWords)

{

Console .WriteLine(e);

}

//method 2

XElement numDoc = new XElement ("Numbers" ,

from num in numbers

select new XElement ("Number" , num));

numDoc.Save( @"C:\Users\SLK\Documents\Visual Studio2010\Projects\LanguageEnhancements\LanguageEnhancements\bin\Debug\Numbers.xml");

}

public static void LinqToSql()

{ // must have "using System.Data.Linq;" to use DataCOntext.

DataContext db = new DataContext (@"Data Source=.\SQLEXPRESS;InitialCatalog=Employee;User ID=sa;Password=sa" );

var regions = from r in db.GetTable< Region >()

select r;

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foreach (var item in regions)

Console .WriteLine(item.Description);

//using Linq to Sql class for this we must use usingLanguageEnhancements.DataAccess;

EmployeeDataContext db1 = new EmployeeDataContext ();

db1.Log = Console .Out;

var productList = from p in db1.Products

select p;

foreach (var p in productList) Console .WriteLine(p.ProductName);

}

}

}

Region.cs

using System;


using System.Linq;

using System.Text;

using System.Data.Linq.Mapping;

namespace LanguageEnhancements

{

//linking this class to sql for this we should add System.Data.Linq to the references. andadd using System.Data.Linq.Mapping;

[ Table ] //table and class names are same so no need to mention table name

public class Region //this is the entity class for Region Table.

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{

[Column (IsPrimaryKey= true )]

public int RegionId { get ; set ; } //property and column name are same so dont haveto specify column name

[Column (Name= "RegionDescription" )] // property is different from column name sowe specify the column name

public string Description { get ; set ; }

}

}

Date post:	02-Apr-2018
Category:	Documents
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