“The data reader has more than one field” error in Entity Framework

Question

I\'m executing this simple query with Entity Framework

db.Database.SqlQuery(\"SELECT * FROM hospital\");

But I got this error

Answer 1

It would be useful to see what the hospital table looks like but assuming something simple like hospital consists of HospitalId and HospitalName then you have a couple of choices.

db.Database.SqlQuery<IEnumerable<string>>("SELECT hospitalName FROM hospital"); //would work if all you're trying to do is get the Name

db.Database.SqlQuery<MyEntity>("SELECT * FROM hospital"); //where you define MyEntity as the same structure as the table would work

db.Database.SqlQuery<IEnumerable<Tuple<int, string>>>("SELECT * FROM hospital"); // would theoretically work although I haven't tried it.  Where the Tuple items would have to match the database types in order.  I.e. if field 1 is an int and field 2 is a string then Tuple<int,string>

Basically the error is the code doesn't know how to stuff the structure of hospital into a string

Answer 2

This solved my issue, some results where not getting the way it was supposed to

string storedProcedure = "Admin_AutoGenerateKeywordsFortblCompany @Company_ID=" + CompId;

var s= db.ExecuteStoreQuery<List<string>>("exec " + storedProcedure).ToList();

here single or multiple results can be caught

Answer 3

You might also get this error if you are trying to execute an INSERT, UPATE or DELETE command

Instead of using SqlQuery use ExecuteSqlCommand

using (var ctx = new SchoolDBEntities())
{
    int noOfRowUpdated = ctx.Database.ExecuteSqlCommand("Update student 
            set studentname ='changed student by command' where studentid=1");

    int noOfRowInserted = ctx.Database.ExecuteSqlCommand("insert into student(studentname) 
            values('New Student')");

    int noOfRowDeleted = ctx.Database.ExecuteSqlCommand("delete from student 
            where studentid=1");
}

For more details visit - http://www.entityframeworktutorial.net/EntityFramework4.3/raw-sql-query-in-entity-framework.aspx

Answer 4

Based on the secound answer that cgotberg gave me, Im going to answer my own question. The problem with that code was that some table's field was not the same as it is in the database(I was looking for the exception but I could not found it, sorry for that) but it actually exist. For some reason i had to add all the fields of the tables to the query string. I mean, i had to write "SELECT hospital_phone, holpital_street, etc, etc FROM hospital", if i write "SELECT hospital_name FROM hospital" the exception occurs.

Hope I've it explained well.