• To log EF standard workflow, use the Log property, that accepts any Action<string> type.

using (var context = new SchoolDBEntities())
{
	context.Database.Log = Console.Write;
	var student = context.Students
		.Where(s => s.StudentName == "Student1").FirstOrDefault();
	student.StudentName = "Edited Name";
	context.SaveChanges();
}

Interception

• EF provides the ability to intercept the context using IDbCommandInterceptor.
• It intercepts before and after it performs the ExecuteNonQuery, ExecuteScalar, ExecuteReader operations to the database.

class EFCommandInterceptor: IDbCommandInterceptor
{
	public void NonQueryExecuted(System.Data.Common.DbCommand command,
		DbCommandInterceptionContext<int> interceptionContext)
	{
		LogInfo("NonQueryExecuted", String.Format(" IsAsync: {0}, Command Text: {1}",
			interceptionContext.IsAsync, command.CommandText));
	}
	
	public void NonQueryExecuting(System.Data.Common.DbCommand command,
		DbCommandInterceptionContext<int> interceptionContext)
	{
		LogInfo("NonQueryExecuting", String.Format(" IsAsync: {0}, Command Text: {1}",
			interceptionContext.IsAsync,  command.CommandText));
	}
	
	public void ReaderExecuted(System.Data.Common.DbCommand command,
		DbCommandInterceptionContextt<System.Data.Common.DbDataReader> interceptionContext)
	{
		LogInfo("ReaderExecuted", String.Format(" IsAsync: {0}, Command Text: {1}",
			interceptionContext.IsAsync, command.CommandText));
	}
	
	public void ReaderExecuting(System.Data.Common.DbCommand command,
		DbCommandInterceptionContext<System.Data.Common.DbDataReader> interceptionContext)
	{
		LogInfo("ReaderExecuting", String.Format(" IsAsync: {0}, Command Text: {1}",
			interceptionContext.IsAsync, command.CommandText));
	}
	
	public void ScalarExecuted(System.Data.Common.DbCommand command,
		DbCommandInterceptionContext<object> interceptionContext)
	{
		LogInfo("ScalarExecuted", String.Format(" IsAsync: {0}, Command Text: {1}",
			interceptionContext.IsAsync, command.CommandText));
	}
	
	public void ScalarExecuting(System.Data.Common.DbCommand command,
		DbCommandInterceptionContext<object> interceptionContext)
	{
		LogInfo("ScalarExecuting", String.Format(" IsAsync: {0}, Command Text: {1}",
			interceptionContext.IsAsync, command.CommandText));
	}
	
	private void LogInfo(string command, string commandText)
	{
		Console.WriteLine("Intercepted on: {0} :- {1} ", command, commandText);
	}
}

• To configure the interceptor, use config file or code-based configuration.

<entityFramework>
	<interceptors>
		<interceptor type="MyNameSpace.EF6CodeConfig, EntityFramework"></interceptor>
		<interceptor type="System.Data.Entity.Infrastructure.Interception.DatabaseLogger, EntityFramework">
	    <parameters>
	      <parameter value="C:\\Temp\\LogOutput.txt" />
	    </parameters>
	  </interceptor>
	</interceptors>
</entityFramework>

public class EF6CodeConfig : DbConfiguration
{
	public EF6CodeConfig()
	{
		AddInterceptor(new EFCommandInterceptor());
	}
}

Logging and intercepting database operations - EF6