Question

I’ve created entity data model for the following database tables in SqlCe:

CREATE TABLE [test_vulnerabilities] (
    [id] INTEGER PRIMARY KEY,
    [description] NTEXT NOT NULL DEFAULT ''
);

CREATE TABLE [test_software_vulnerabilities]
(
    [id] INTEGER PRIMARY KEY IDENTITY,
    [vulnerability_id] INTEGER NOT NULL
                       REFERENCES [test_vulnerabilities]([id]),
    [details] NTEXT NOT NULL DEFAULT ''
);

Entities (created by adding entity model based on existing database):

entity Vulnerability in set Vulnerabilities
    Id int
    Description string
    Software ICollection<SoftwareVulnerability> - navigation property

entity SoftwareVulnerability in set SoftwareVulnerabilities
    Id int
    Details string
    VulnerabilityId int
    Vulnerability Vulnerability - navigation property

and executing the following query:

        var query = (from v in entities.Vulnerabilities.Include("Software")
                     where v.Id == id && v.Software.Count > 0
                     select v);

it is very-very-very slow because the generated SQL joins vulnerabilities with software_vulnerability with left outer join.

Is there any way to simply say that I want only vulnerabilities with non-empty software_vulnerability and the INNER JOIN is ok?

Thanks!

Answer 1

No. You don’t have control over used joins. You can try to revert the query:

var query = (from s in entities.SofwareVulnerabilities.Include("Vulnerability")
             where s.VulnerabilityId == id
             select s);

You will get all software vulnerabilities for your single expected vulnerability and the vulnerability will be included. If your relation is from software vulnerability is correctly configured as mandatory it should hopefully use inner join.