来自 EF SQL 的自定义 IQueryable 用于 Azure 移动应用服务

Question

I need to have a SQL query added on to my IQueryable in the Azure Mobile App Service backend table controller. I need the ItemLibrary table to have a default query as shown. And either replace the return Query() that is part of the default table controller or merge it with it.

This is what I need to do for the GetAllItemLibraries but I can't get it to work:

public class ItemLibraryController : TableController<ItemLibrary>
{
    protected override void Initialize(HttpControllerContext controllerContext)
    {
        base.Initialize(controllerContext);

        MIIToolsContext context = new MIIToolsContext();
        DomainManager = new EntityDomainManager<ItemLibrary>(context, Request, enableSoftDelete: true);
    }

    // GET tables/ItemLibrary
    public IQueryable<ItemLibrary> GetAllItemLibraries()
    {
        using (MIIToolsContext context = new MIIToolsContext())
        {
            string sqlQueryString = "SELECT * FROM dbo.ItemSpecification WHERE Id IN (SELECT DISTINCT EquipmentItemID FROM dbo.SiteEquipment WHERE EquipmentSiteID = '8FA79274-C5CC-4610-9D6E-A7062D3CE966')";
            string test = "SELECT TOP 10 * FROM dbo.ItemSpecification";

            return context.ItemLibrary.SqlQuery(sqlQueryString).AsQueryable();
            // return context.ItemLibrary.SqlQuery(test).AsQueryable();
        }

        // possibly merge the SQL IQueryable with the default query?
        // Query.Union([sqlquery])

        // default query
        // return Query();
    }
}

I could do the query in Linq and not SQL, but I have no idea how to reference the SiteEquipment table from the context of the ItemLibrary table controller. I need that to be the default query but still have it tack on any OData from a client.

For those of you who don't know anything about Azure Mobile App Service and want to comment here is an example of the out of the box default table controller wrapper:

public class ExampleController : TableController<Example>
{
        protected override void Initialize(HttpControllerContext controllerContext)
        {
            base.Initialize(controllerContext);
            MobileServiceContext context = new MobileServiceContext();
            DomainManager = new EntityDomainManager<Example>(context, Request, enableSoftDelete: true);
        }

        // GET tables/Example
        public IQueryable<Example> GetAllExample()
        {
            return Query();
        }

        // GET tables/Example/48D68C86-6EA6-4C25-AA33-223FC9A27959
        public SingleResult<Example> GetExample(string id)
        {
            return Lookup(id);
        }

        // PATCH tables/Example/48D68C86-6EA6-4C25-AA33-223FC9A27959
        public Task<Example> PatchExample(string id, Delta<Example> patch)
        {
            return UpdateAsync(id, patch);
        }

        // POST tables/Example
        public async Task<IHttpActionResult> PostExample(Example item)
        {
            Example current = await InsertAsync(item);
            return CreatedAtRoute("Tables", new { id = current.Id }, current);
        }

        // DELETE tables/Example/48D68C86-6EA6-4C25-AA33-223FC9A27959
        public Task DeleteExample(string id)
        {
            return DeleteAsync(id);
        }
}

Answer 1

Don't know if this is the most elegant way but it is working as needed:

public IQueryable<ItemLibrary> GetAllItemLibrarys(string site)
        {
            using (MIIToolsContext context = new MIIToolsContext())
            {
                //create sql param for site param
                var siteParam = new SqlParameter("@Site", site);

                //use sql to access siteequipment id's by current project site
                var items = context.ItemLibrary.SqlQuery("Select * from dbo.MIIToolsItemLibrary where Id in (SELECT DISTINCT ItemLibraryID FROM dbo.MIIToolsEquipment WHERE ProjectSiteID = @Site)", siteParam).Select(i => i.Id).ToList();

                //use linq on local tablecontroller generated query against sql id results
                return Query().Where(i => items.Any(a => a == i.Id));
            }

            //not using default query
            //return Query();
        }

Since I didn't know how (or the best way) to access the SiteEquipment linq query object I just used sql for that part and then was able to insert the result into the provided ItemLibrary Query so I can still run odata queries against it.

I also added a "site" parameter so the mobile client applications are only dealing with items related to that project site. just what I wanted.

Answer 2

I have test it, I think your query string doesn't work because of EntityData . So I changed your test string and test it.

It works!

public IQueryable<ItemLibrary> GetAllItemLibrarys()
{
        using (ZUMOAPPNAMEContext context = new ZUMOAPPNAMEContext())
        {
            string sqlQueryString = "Select * from dbo.ItemSpecification where Id in (SELECT DISTINCT EquipmentItemID FROM dbo.SiteEquipment WHERE EquipmentSiteID = '8FA79274-C5CC-4610-9D6E-A7062D3CE966')";
            string test = "Select TOP 10 * from dbo.ItemSpecification";
            // Due to EntityData, so sql like below
            test = @"Select TOP 10 *,'111' Id,0x0000000000000FA4 Version,null CreatedAt,null UpdatedAt,CAST(COALESCE(NULL,0) AS BIT) as Deleted from dbo.ItemSpecification";
            var a = context.ItemLibrary.SqlQuery(test).ToList().AsQueryable();
            return a;
        }
}