How do I view the SQL generated by the Entity Framework?

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别那么骄傲
别那么骄傲 2020-11-21 05:35

How do I view the SQL generated by entity framework ?

(In my particular case I\'m using the mysql provider - if it matters)

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  •  感动是毒
    2020-11-21 06:15

    While there are good answers here, none solved my problem completely (I wished to get the entire SQL statement, including Parameters, from the DbContext from any IQueryable. The following code does just that. It is a combination of code snippets from Google. I have only tested it with EF6+.

    Just an aside, this task took me way longer than I thought it would. Abstraction in Entity Framework is a bit much, IMHO.

    First the using. You will need an explicit reference to '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;
    

    The following class converts an IQueryable into a DataTable. Modify as your need may be:

    public class EntityFrameworkCommand
    {
        DbContext Context;
    
        string SQL;
    
        ObjectParameter[] Parameters;
    
        public EntityFrameworkCommand Initialize(DbContext context, IQueryable query)
        {
            Context = context;
            var dbQuery = query as DbQuery;
            // 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;
            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;
                cmd.Parameters.AddRange(Parameters.Select(p => new SqlParameter("@" + p.Name, p.Value)).ToArray());
                using (var da = DbProviderFactories.GetFactory(connection).CreateDataAdapter())
                {
                    da.SelectCommand = cmd;
                    da.Fill(dt);
                }
            }
            if (!(state == ConnectionState.Open))
                connection.Close();
            return dt;
        }
    }
    

    To use, simply call it as below:

    var context = new MyContext();
    var data = ....//Query, return type can be anonymous
        .AsQueryable();
    var dt = new EntityFrameworkCommand()
        .Initialize(context, data)
        .GetData();
    

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