How do I get Linq to SQL to recognize the result set of a dynamic Stored Procedure?

Question

I\'m using Linq-to-SQL with a SQL Server backend (of course) as an ORM for a project. I need to get the result set from a stored procedure that returns from a dynamically-cr

Answer 1

First - IMPORTANT - your SQL is vulnerable to injection; the inner command should be parameterized:

if len(@l_author) > 0
set @sql =  @sql + ' and author like ''%''+@author+''%'''

EXECUTE sp_executesql  @sql, N'@author varchar(100)', @L_author

This passes the value of @L_author in as the @author parameter in the dynamic command - preventing injection attacks.

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Second - you don't really need the temp table. It isn't doing anything for you... you just INSERT and SELECT. Perhaps just EXEC and let the results flow to the caller naturally?

In other circumstances a table-variable would be more appropriate, but this doesn't work with INSERT/EXEC.

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Are the columns the same for every call? If so, either write the dbml manually, or use a temp SP (just with "WHERE 1=0" or something) so that the SET FMT_ONLY ON can work.

If not (different columns per usage), then there isn't an easy answer. Perhaps use regular ADO.NET in this case (ExecuteReader/IDataReader - and perhaps even DataTable.Fill).

Of course, you could let LINQ take the strain... (C#):

...
if(!string.IsNullOrEmpty(author)) {
    query = query.Where(row => row.Author.Contains(author));
}
...

etc

Answer 2

There's no real easy way to do this. I've had the same problem in the past. I think the issue is that Linq to Sql has no way of "figuring out" which type will be returned since you're building up the SELECT statement at execution time. What I did to get around this, was in the stored proc, I did just a select and selected all the columns that I possibly needed. Then, I had Linq to Sql generate the function based on that. Then, I went back to SQL and changed the stored proc back to the way it's supposed to be. The trick here is not to regenerate your DBML.