概述：EF Core 没有直接提供像 EF6 那样方便的在日志中记录最终生成的 SQL 的功能，可以通过官方提供的日志记录(Microsoft.Extensions.Logging)实现。
零 日志提供程序
0.EF Core 日志记录当前需要一个本身配置有一个或多个ILoggerProvider的ILoggerFactory。以下包中是常见的提供程序：
Microsoft.Extensions.Logging.Console：一个简单的控制台记录器。Microsoft.Extensions.Logging.AzureAppServices：支持Azure应用服务诊断日志和日志流功能。Microsoft.Extensions.Logging.Debug：使用System.Diagnostics.Debug.WriteLine()调试器监视日志。Microsoft.Extensions.Logging.EventLog：记录到WIndows事件日志。Microsoft.Extensions.Logging.EventSource支持EventSource/EventListener。Microsoft.Extensions.Logging.TraceSource：会向使用System.Diagnostics.TraceSource.TraceEvent()的跟踪侦听器。
一 使用 ILoggerProvider 查看生成的SQL语句
** 0.添加包 Microsoft.Extensions.Logging.Debug
** 1.DbContext文件,添加引用
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Debug;
** 2.DbContext文件里定义一个日志工厂
// Microsoft.Extensions.Logging.Debug
public static readonly LoggerFactory MyLoggerFactory = new LoggerFactory(new[] {
new DebugLoggerProvider()
});
//Microsoft.Extensions.Logging.Console
public static readonly LoggerFactory MyLoggerFactory = new LoggerFactory(new[] {
new ConsoleLoggerProvider((category, level) => category == DbLoggerCategory.Database.Command.Name&& level == LogLevel.Information, true)
});
** 3.在DbContext文件OnConfiguring连接字符前添加日志UseLoggerFactory(MyLoggerFactory)
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
if (!optionsBuilder.IsConfigured)
{
optionsBuilder.UseLoggerFactory(MyLoggerFactory).UseMySql("Server=xxx;User Id=xxx;Password=xxx;Database=bebefocus;Persist Security Info=True;");
// optionsBuilder.UseLoggerFactory(MyLoggerFactory).UseSqlServer("Server=xxx;User Id=xxx;Password=xxx;Database=bebefocus;Persist Security Info=True;");
}
}
** 4.运行查看 在输出面板里查看(菜单：视图->输出)
Microsoft.EntityFrameworkCore.Database.Command: Information: Executing DbCommand [Parameters=[@__param_AssessObjectType_0='?' (DbType = Int32)], CommandType='Text', CommandTimeout='150000']
SELECT COUNT(*)
FROM [ChildTemp] AS [c]
WHERE (([c].[AssessObjectType] = @__param_AssessObjectType_0) AND ([c].[AssessObjectType] IS NOT NULL AND @__param_AssessObjectType_0 IS NOT NULL)) OR ([c].[AssessObjectType] IS NULL AND @__param_AssessObjectType_0 IS NULL)
Microsoft.EntityFrameworkCore.Database.Command: Information: Executing DbCommand [Parameters=[@__param_AssessObjectType_0='?' (DbType = Int32)], CommandType='Text', CommandTimeout='150000']
SELECT [c].[ChildTempID], [c].[AssessLevelProportion], [c].[AssessName], [c].[AssessObjectType], [c].[AssessObjectValue], [c].[AssessWeightMustFull], [c].[CreateTime], [c].[Creator], [c].[IsSubmitSummary], [c].[Modifier], [c].[ModifyTime], [c].[Remark], [c].[TempLevel], [c].[TempName], [c].[TempType], [c0].[ChildTempAeesesedObjectID], [c0].[ChildTempID], [c0].[CreateTime], [c0].[Creator], [c0].[Name], [c0].[ObjectType], [c0].[ObjectValue], [c1].[ChildTempAssessItemID], [c1].[BasicIndicator], [c1].[ChallengeIndicator], [c1].[ChildTempID], [c1].[CreateTime], [c1].[Creator], [c1].[Explain], [c1].[Modifier], [c1].[ModifyTime], [c1].[ShowIndex], [c1].[Title], [c1].[Weight]
FROM [ChildTemp] AS [c]
LEFT JOIN [ChildTempAssessedObject] AS [c0] ON [c].[ChildTempID] = [c0].[ChildTempID]
LEFT JOIN [ChildTempAssessItem] AS [c1] ON [c].[ChildTempID] = [c1].[ChildTempID]
WHERE (([c].[AssessObjectType] = @__param_AssessObjectType_0) AND ([c].[AssessObjectType] IS NOT NULL AND @__param_AssessObjectType_0 IS NOT NULL)) OR ([c].[AssessObjectType] IS NULL AND @__param_AssessObjectType_0 IS NULL)
ORDER BY [c].[CreateTime] DESC, [c].[ChildTempID], [c0].[ChildTempAeesesedObjectID], [c1].[ChildTempAssessItemID]