如何查看实体框架生成的SQL ?
(在我的特殊情况下，我使用mysql提供商-如果它重要)
当前回答
虽然这里有很好的答案，但没有一个完全解决了我的问题(我希望从任何IQueryable DbContext中获得整个SQL语句，包括参数)。下面的代码就是这样做的。它是来自谷歌的代码片段的组合。我只用EF6+测试过。
说句题外话，这项任务花的时间比我想象的要长得多。恕我直言，实体框架中的抽象有点太多了。
首先是使用。您需要显式引用'System.Data.Entity.dll'。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.SqlClient;
using System.Data.Common;
using System.Data.Entity.Core.Objects;
using System.Data.Entity;
using System.Data;
using System.Data.Entity.Infrastructure;
using System.Reflection;
下面的类将一个IQueryable转换为一个DataTable。根据您的需要修改:
public class EntityFrameworkCommand
{
DbContext Context;
string SQL;
ObjectParameter[] Parameters;
public EntityFrameworkCommand Initialize<T>(DbContext context, IQueryable<T> query)
{
Context = context;
var dbQuery = query as DbQuery<T>;
// get the IInternalQuery internal variable from the DbQuery object
var iqProp = dbQuery.GetType().GetProperty("InternalQuery", BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);
var iq = iqProp.GetValue(dbQuery, null);
// get the ObjectQuery internal variable from the IInternalQuery object
var oqProp = iq.GetType().GetProperty("ObjectQuery", BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);
var objectQuery = oqProp.GetValue(iq, null) as ObjectQuery<T>;
SQL = objectQuery.ToTraceString();
Parameters = objectQuery.Parameters.ToArray();
return this;
}
public DataTable GetData()
{
DataTable dt = new DataTable();
var connection = Context.Database.Connection;
var state = connection.State;
if (!(state == ConnectionState.Open))
connection.Open();
using (var cmd = connection.CreateCommand())
{
cmd.CommandText = SQL;
foreach (var p in Parameters)
{
var param = cmd.CreateParameter();
param.Name = "@" + p.Name;
param.Value = p.Value;
cmd.Parameters.Add(param);
}
using (var da = DbProviderFactories.GetFactory(connection).CreateDataAdapter())
{
da.SelectCommand = cmd;
da.Fill(dt);
}
}
if (!(state == ConnectionState.Open))
connection.Close();
return dt;
}
}
要使用，只需如下所示调用它:
var context = new MyContext();
var data = ....//Query, return type can be anonymous
.AsQueryable();
var dt = new EntityFrameworkCommand()
.Initialize(context, data)
.GetData();
其他回答
在EF 4.1中可以执行以下操作:
var result = from x in appEntities
where x.id = 32
select x;
System.Diagnostics.Trace.WriteLine(result .ToString());
这将为您提供生成的SQL。
Necromancing。 当搜索任何。net框架的解决方案时，这个页面是第一个搜索结果，所以这里作为一个公共服务，它是如何在EntityFrameworkCore(用于。net Core 1和2)中完成的:
var someQuery = (
from projects in _context.projects
join issues in _context.issues on projects.Id equals issues.ProjectId into tmpMapp
from issues in tmpMapp.DefaultIfEmpty()
select issues
) //.ToList()
;
// string sql = someQuery.ToString();
// string sql = Microsoft.EntityFrameworkCore.IQueryableExtensions.ToSql(someQuery);
// string sql = Microsoft.EntityFrameworkCore.IQueryableExtensions1.ToSql(someQuery);
// using Microsoft.EntityFrameworkCore;
string sql = someQuery.ToSql();
System.Console.WriteLine(sql);
然后这些扩展方法(IQueryableExtensions1用于。net Core 1.0, IQueryableExtensions用于。net Core 2.0):
using System;
using System.Linq;
using System.Reflection;
using Microsoft.EntityFrameworkCore.Internal;
using Microsoft.EntityFrameworkCore.Query;
using Microsoft.EntityFrameworkCore.Query.Internal;
using Microsoft.EntityFrameworkCore.Storage;
using Remotion.Linq.Parsing.Structure;
namespace Microsoft.EntityFrameworkCore
{
// https://stackoverflow.com/questions/1412863/how-do-i-view-the-sql-generated-by-the-entity-framework
// http://rion.io/2016/10/19/accessing-entity-framework-core-queries-behind-the-scenes-in-asp-net-core/
public static class IQueryableExtensions
{
private static readonly TypeInfo QueryCompilerTypeInfo = typeof(QueryCompiler).GetTypeInfo();
private static readonly FieldInfo QueryCompilerField = typeof(EntityQueryProvider).GetTypeInfo().DeclaredFields
.First(x => x.Name == "_queryCompiler");
private static readonly PropertyInfo NodeTypeProviderField =
QueryCompilerTypeInfo.DeclaredProperties.Single(x => x.Name == "NodeTypeProvider");
private static readonly MethodInfo CreateQueryParserMethod =
QueryCompilerTypeInfo.DeclaredMethods.First(x => x.Name == "CreateQueryParser");
private static readonly FieldInfo DataBaseField =
QueryCompilerTypeInfo.DeclaredFields.Single(x => x.Name == "_database");
private static readonly PropertyInfo DatabaseDependenciesField =
typeof(Database).GetTypeInfo().DeclaredProperties.Single(x => x.Name == "Dependencies");
public static string ToSql<TEntity>(this IQueryable<TEntity> query) where TEntity : class
{
if (!(query is EntityQueryable<TEntity>) && !(query is InternalDbSet<TEntity>))
{
throw new ArgumentException("Invalid query");
}
var queryCompiler = (QueryCompiler) QueryCompilerField.GetValue(query.Provider);
var nodeTypeProvider = (INodeTypeProvider) NodeTypeProviderField.GetValue(queryCompiler);
var parser = (IQueryParser) CreateQueryParserMethod.Invoke(queryCompiler, new object[] {nodeTypeProvider});
var queryModel = parser.GetParsedQuery(query.Expression);
var database = DataBaseField.GetValue(queryCompiler);
var databaseDependencies = (DatabaseDependencies) DatabaseDependenciesField.GetValue(database);
var queryCompilationContext = databaseDependencies.QueryCompilationContextFactory.Create(false);
var modelVisitor = (RelationalQueryModelVisitor) queryCompilationContext.CreateQueryModelVisitor();
modelVisitor.CreateQueryExecutor<TEntity>(queryModel);
var sql = modelVisitor.Queries.First().ToString();
return sql;
}
}
public class IQueryableExtensions1
{
private static readonly TypeInfo QueryCompilerTypeInfo = typeof(QueryCompiler).GetTypeInfo();
private static readonly FieldInfo QueryCompilerField = typeof(EntityQueryProvider).GetTypeInfo()
.DeclaredFields
.First(x => x.Name == "_queryCompiler");
private static readonly PropertyInfo NodeTypeProviderField =
QueryCompilerTypeInfo.DeclaredProperties.Single(x => x.Name == "NodeTypeProvider");
private static readonly MethodInfo CreateQueryParserMethod =
QueryCompilerTypeInfo.DeclaredMethods.First(x => x.Name == "CreateQueryParser");
private static readonly FieldInfo DataBaseField =
QueryCompilerTypeInfo.DeclaredFields.Single(x => x.Name == "_database");
private static readonly FieldInfo QueryCompilationContextFactoryField = typeof(Database).GetTypeInfo()
.DeclaredFields.Single(x => x.Name == "_queryCompilationContextFactory");
public static string ToSql<TEntity>(IQueryable<TEntity> query) where TEntity : class
{
if (!(query is EntityQueryable<TEntity>) && !(query is InternalDbSet<TEntity>))
{
throw new ArgumentException("Invalid query");
}
var queryCompiler = (IQueryCompiler) QueryCompilerField.GetValue(query.Provider);
var nodeTypeProvider = (INodeTypeProvider) NodeTypeProviderField.GetValue(queryCompiler);
var parser =
(IQueryParser) CreateQueryParserMethod.Invoke(queryCompiler, new object[] {nodeTypeProvider});
var queryModel = parser.GetParsedQuery(query.Expression);
var database = DataBaseField.GetValue(queryCompiler);
var queryCompilationContextFactory =
(IQueryCompilationContextFactory) QueryCompilationContextFactoryField.GetValue(database);
var queryCompilationContext = queryCompilationContextFactory.Create(false);
var modelVisitor = (RelationalQueryModelVisitor) queryCompilationContext.CreateQueryModelVisitor();
modelVisitor.CreateQueryExecutor<TEntity>(queryModel);
var sql = modelVisitor.Queries.First().ToString();
return sql;
}
}
}
实体框架4解决方案
这里的大多数答案都是ef6特异性的。这里有一个给那些还在使用EF4的人。
这个方法替换了@p__linq__0/etc。参数的实际值，所以您可以复制并粘贴输出到SSMS并运行它或调试它。
/// <summary>
/// Temporary debug function that spits out the actual SQL query LINQ is generating (with parameters)
/// </summary>
/// <param name="q">IQueryable object</param>
private string Debug_GetSQLFromIQueryable<T>(IQueryable<T> q)
{
System.Data.Objects.ObjectQuery oq = (System.Data.Objects.ObjectQuery)q;
var result = oq.ToTraceString();
List<string> paramNames = new List<string>();
List<string> paramVals = new List<string>();
foreach (var parameter in oq.Parameters)
{
paramNames.Add(parameter.Name);
paramVals.Add(parameter.Value == null ? "NULL" : ("'" + parameter.Value.ToString() + "'"));
}
//replace params in reverse order, otherwise @p__linq__1 incorrectly replaces @p__linq__10 for instance
for (var i = paramNames.Count - 1; i >= 0; i--)
{
result = result.Replace("@" + paramNames[i], paramVals[i]);
}
return result;
}
我正在做集成测试，需要在实体框架核心2.1中调试生成的SQL语句，所以我使用DebugLoggerProvider或ConsoleLoggerProvider，如下所示:
[Fact]
public async Task MyAwesomeTest
{
//setup log to debug sql queries
var loggerFactory = new LoggerFactory();
loggerFactory.AddProvider(new DebugLoggerProvider());
loggerFactory.AddProvider(new ConsoleLoggerProvider(new ConsoleLoggerSettings()));
var builder = new DbContextOptionsBuilder<DbContext>();
builder
.UseSqlServer("my connection string") //"Server=.;Initial Catalog=TestDb;Integrated Security=True"
.UseLoggerFactory(loggerFactory);
var dbContext = new DbContext(builder.Options);
........
下面是Visual Studio控制台的输出示例:
从实体框架核心5.0+开始，可以简单地覆盖DbContext中的onconfiguration方法一次用于日志记录。这也适用于Single()或Any()查询。
日志记录到调试窗口:
public class ExampleDbContext : DbContext
{
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
// using System.Diagnostics;
optionsBuilder.LogTo(message => Debug.WriteLine(message));
}
}
登录控制台:
public class ExampleDbContext : DbContext
{
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.LogTo(Console.WriteLine);
}
}
更多详细信息，包括日志级别和过滤:https://learn.microsoft.com/en-us/ef/core/logging-events-diagnostics/simple-logging
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