Linq to Sql: 如何快速清除表

You could do a normal SQL truncate or delete command, using the DataContext.ExecuteCommand method:

context.ExecuteCommand("DELETE FROM Entity");

Or

context.ExecuteCommand("TRUNCATE TABLE Entity");

The way you are deleting is taking long because Linq to SQL generates a DELETE statement for each entity, there are other type-safe approaches to do batch deletes/updates, check the following articles:

• Batch Updates and Deletes with LINQ to SQL
• LINQ to SQL Extension: Batch Deletion with Lambda Expression

Unfortunately LINQ-to-SQL doesn't execute set based queries very well.

You would assume that

context.Entities.DeleteAllOnSubmit(context.Entities);
context.SubmitChanges();

will translate to something like

DELETE FROM [Entities]

but unfortunately it's more like

DELETE FROM [dbo].[Entities] WHERE ([EntitiesId] = @p0) AND ([Column1] = @p1) ...
DELETE FROM [dbo].[Entities] WHERE ([EntitiesId] = @p0) AND ([Column1] = @p1) ...
DELETE FROM [dbo].[Entities] WHERE ([EntitiesId] = @p0) AND ([Column1] = @p1) ...

You'll find the same when you try to do bulk update in LINQ-to-SQL. Any more than a few hundred rows at a time and it's simply going to be too slow.

If you need to do batch operations & you're using LINQ-to-SQL, you need to write stored procedures.

I like using an Extension Method, per the following:

public static class LinqExtension
{
public static void Truncate<TEntity>(this Table<TEntity> table) where TEntity : class
{
var rowType = table.GetType().GetGenericArguments()[0];
var tableName = table.Context.Mapping.GetTable(rowType).TableName;
var sqlCommand = String.Format("TRUNCATE TABLE {0}", tableName);
table.Context.ExecuteCommand(sqlCommand);
}
}

The Below c# code is used to Insert/Update/Delete/DeleteAll on a database table using LINQ to SQL

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;


namespace PracticeApp
{
class PracticeApp
{
public void InsertRecord(string Name, string Dept) {
LinqToSQLDataContext LTDT = new LinqToSQLDataContext();
LINQTOSQL0 L0 = new LINQTOSQL0 { NAME = Name, DEPARTMENT = Dept };
LTDT.LINQTOSQL0s.InsertOnSubmit(L0);
LTDT.SubmitChanges();
}


public void UpdateRecord(int ID, string Name, string Dept)
{
LinqToSQLDataContext LTDT = new LinqToSQLDataContext();
LINQTOSQL0 L0 = (from item in LTDT.LINQTOSQL0s where item.ID == ID select item).FirstOrDefault();
L0.NAME = Name;
L0.DEPARTMENT = Dept;
LTDT.SubmitChanges();
}


public void DeleteRecord(int ID)
{
LinqToSQLDataContext LTDT = new LinqToSQLDataContext();
LINQTOSQL0 L0;
if (ID != 0)
{
L0 = (from item in LTDT.LINQTOSQL0s where item.ID == ID select item).FirstOrDefault();
LTDT.LINQTOSQL0s.DeleteOnSubmit(L0);
}
else
{
IEnumerable<LINQTOSQL0> Data = from item in LTDT.LINQTOSQL0s where item.ID !=0 select item;
LTDT.LINQTOSQL0s.DeleteAllOnSubmit(Data);
}
LTDT.SubmitChanges();
}


static void Main(string[] args) {
Console.Write("* Enter Comma Separated Values to Insert Records\n* To Delete a Record Enter 'Delete' or To Update the Record Enter 'Update' Then Enter the Values\n* Dont Pass ID While Inserting Record.\n* To Delete All Records Pass 0 as Parameter for Delete.\n");
var message = "Successfully Completed";
try
{
PracticeApp pa = new PracticeApp();
var enteredValue = Console.ReadLine();
if (Regex.Split(enteredValue, ",")[0] == "Delete")
{
Console.Write("Delete Operation in Progress...\n");
pa.DeleteRecord(Int32.Parse(Regex.Split(enteredValue, ",")[1]));
}
else if (Regex.Split(enteredValue, ",")[0] == "Update")
{
Console.Write("Update Operation in Progress...\n");
pa.UpdateRecord(Int32.Parse(Regex.Split(enteredValue, ",")[1]), Regex.Split(enteredValue, ",")[2], Regex.Split(enteredValue, ",")[3]);
}
else
{
Console.Write("Insert Operation in Progress...\n");
pa.InsertRecord(Regex.Split(enteredValue, ",")[0], Regex.Split(enteredValue, ",")[1]);
}
}
catch (Exception ex)
{
message = ex.ToString();
}
Console.Write(message);
Console.ReadLine();
}
}
}

you could also use this:

Public void BorraFilasTabla()
{
using(basededatos db = new basededatos())
{
var ListaParaBorrar = db.Tabla.Tolist();
db.Tabla.RemoveRange(ListaParaBorrar);
}
}