在 Entity Framework Core 2.0 中执行 SQL 命令删除表中的所有数据 [英] Execute SQL command in Entity Framework Core 2.0 to delete all data in a table

问题描述

我想从 Entity Framework Core 2.0 执行 SQL 命令，但我不知道如何执行.

1.- 我需要这样做的原因是我想从数据库表中删除所有数据，并且使用 Context.remove 或 Context.removeRange 会对 DB 产生多次调用(表中的每个数据调用一次).

2.- 我已经读到有一个方法 .ExecuteSqlCommand 可以实现这一点，但是我的 Context.Database 中没有该方法(也许在 Core 2.0 中它被删除了?).这是信息的来源:在实体框架核心和 UWP 中删除表

所以，基本上我需要使用 EF Core 2.0 从代码中删除一个表，据我所知，我需要为此执行 SQL 命令.

谢谢.

这是我的 .csproj，以防万一我遗漏了什么

<属性组><TargetFramework>netcoreapp2.0</TargetFramework><AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback></PropertyGroup><项目组><PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0"/><PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="2.0.0" PrivateAssets="All"/><PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="2.0.0" PrivateAssets="All"/></项目组><项目组><!--<PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.1.1"/>--><DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet" Version="2.0.0"/><DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="2.0.0"/></项目组></项目>

解决方案

确保您引用 Microsoft.EntityFrameworkCore 以包含允许您执行原始 SQL 命令的所有必要扩展方法.

从源代码库中我找到了 ExecuteSqlCommand 和相关的扩展方法

int count = await context.Database.ExecuteSqlCommandAsync("DELETE FROM [Blogs]");

找到一篇建议使用 ADO.Net 的文章.

首先从上下文中获取一个连接，创建一个命令并执行该命令.

using (var connection = context.Database.GetDbConnection()) {等待 connection.OpenAsync();使用 (var 命令 = connection.CreateCommand()) {command.CommandText = "从 [博客] 中删除";var result = await command.ExecuteNonQueryAsync();}}

I want to execute an SQL command from Entity Framework Core 2.0, but I can't figure out how to do so.

1.- The reason why I need to, is that I want to delete all data from a database table, and using Context.remove or Context.removeRange would produce many calls to DB (one for each data in the table).

2.- I've read that there is a method .ExecuteSqlCommand to accomplish that, but that method is not present in my Context.Database (maybe in Core 2.0 it was removed?). Here is the source of the info: Dropping table In Entity Framework Core and UWP

So, basically I need to delete a table from code using EF Core 2.0 and, as far as I know, I need to execute a SQL command for that.

Thank you.

Here is my .csproj, just in case i'm missing something

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp2.0</TargetFramework>
    <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="2.0.0" PrivateAssets="All" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="2.0.0" PrivateAssets="All" />    
  </ItemGroup>

  <ItemGroup>
    <!--<PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.1.1" />    -->
    <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet" Version="2.0.0" />
    <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="2.0.0" />
  </ItemGroup>

</Project>

解决方案

Ensure that you reference Microsoft.EntityFrameworkCore to include all the necessary extension methods that would allow you to execute raw SQL commands.

From the source repository I found ExecuteSqlCommand and related extension methods

int count = await context.Database.ExecuteSqlCommandAsync("DELETE FROM [Blogs]");

Found an article that suggested using ADO.Net.

First you grab a connection from the context, create a command and execute that.

using (var connection = context.Database.GetDbConnection()) {
    await connection.OpenAsync();     
    using (var command = connection.CreateCommand()) {
        command.CommandText = "DELETE FROM [Blogs]";
        var result = await command.ExecuteNonQueryAsync();
    }
}

这篇关于在 Entity Framework Core 2.0 中执行 SQL 命令删除表中的所有数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！