Get multiple values from querying db with entity framework

Question

I've been thinking this for a while. Is there an easy way to use the result querying a database twice without storing the result of the query in some variable? Say I have a

string ResearchAdmin;

where I want to put the 'FirstName' and 'Surname' found in 2 different columns in a 'ProjectResearcher' table in the database. Can I query the database just once (using say entity framework), and get both columns without storing the entire table's data.

To illustrate my point, doing the code below will I think query the database twice, once to get the 'FirstName', once to get the 'Surname':

ResearchAdmin = db.ProjectResearcher.FirstOrDefault(r => r.ProjectId == project.ProjectId).Researcher.FirstName + " " + db.ProjectResearcher.FirstOrDefault(r => r.ProjectId == project.ProjectId).Researcher.Surname

To run the query once I can do the following:

Researcher researchAdmin = db.ProjectResearcher.FirstOrDefault(r => r.ProjectId == project.ProjectId).Researcher;
String researchAdminName = researchAdmin.FirstName + " " + researchAdmin.Surname;

What I'm wondering is if I can do the first option somehow without querying the database twice.

Thewads · Accepted Answer · 2014-03-18 10:52:58Z

2

You could do something like this:

String researchAdminName = db.ProjectResearcher.Where(r => r.ProjectId == project.ProjectId)
        .Select(r => r.FirstName + " " + r.Surname).FirstOrDefault();

Just have to be a little careful that whatever you are putting into the select statement is supported by linq to entities, but simple string concatenation is.

answered Mar 18, 2014 at 10:52

Thewads

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yonsk · Accepted Answer · 2014-03-18 11:31:28Z

1

Thewads answer looks correct and it will give you what you need.

An alternative: Wrap logic in Stored Proc (certainly an overkill here) but for more complex manipulation its prob. better as SQL server will have a cached plan and will be faster.

answered Mar 18, 2014 at 11:31

yonsk

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