BlazarTech.QueryableValues.EF6.SqlServer 1.0.0-rc.2

QueryableValues for EF6

This library allows you to efficiently compose an IEnumerable<T> in your Entity Framework 6 (non-core) queries when using the SQL Server Provider. This is accomplished by using the AsQueryableValues extension method available on the DbContext class. Everything is evaluated on the server with a single round trip, in a way that preserves the query's execution plan, even when the values behind the IEnumerable<T> are changed on subsequent executions.

The supported types for T are: Byte, Int16, Int32, Int64, Guid, and String.

For a detailed explanation of the problem solved by QueryableValues, please continue reading here.

💡 This is a streamlined version of the original QueryableValues for Entity Framework Core, which I have adapted to provide some of its features on Entity Framework 6.

💡 Are you on Entity Framework Core? Use the original version of QueryableValues instead.

When Should You Use It?

The AsQueryableValues extension method is intended for queries that are dependent upon a non-constant sequence of external values. In such cases, the underlying SQL query will be efficient on subsequent executions.

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Getting Started

Installation

QueryableValues for EF6 is distributed as a NuGet Package. You can install it using the command below in your NuGet Package Manager Console window in Visual Studio:

Install-Package BlazarTech.QueryableValues.EF6.SqlServer

How Do You Use It?

The AsQueryableValues extension method is provided by the BlazarTech.QueryableValues namespace; therefore, you must add the following using directive to your source code file for it to appear as a method of your DbContext instance:

using BlazarTech.QueryableValues;

💡 If you access your DbContext via an interface, you can also make the AsQueryableValues extension methods available on it by inheriting from the IQueryableValuesEnabledDbContext interface.

Below are a few examples composing a query using the values provided by an IEnumerable<T>.

Examples

Using the Contains LINQ method:

// Sample values.
IEnumerable<int> values = Enumerable.Range(1, 10);

// This intermediary variable is needed to avoid a NotSupportedException
// with the message: "LINQ to Entities does not recognize the method...".
// Seems to be caused by the use of the Contains method.
var qvQuery = dbContext.AsQueryableValues(values);

// Example #1 (LINQ method syntax)
var myQuery1 = dbContext.TestData
    .Where(e => qvQuery.Contains(e.Id))
    .Select(i => new
    {
        i.Id,
        i.GuidValue
    })
    .ToList();
                
// Example #2 (LINQ query syntax)
var myQuery2 = (
    from e in dbContext.TestData
    where qvQuery.Contains(e.Id)
    select new
    {
        e.Id,
        e.GuidValue
    })
    .ToList();

Using the Join LINQ method:

// Sample values.
IEnumerable<int> values = Enumerable.Range(1, 10);

// Here we can make direct use of the AsQueryableValues extension without issues.

// Example #1 (LINQ method syntax)
var myQuery1 = dbContext.TestData
    .Join(
        dbContext.AsQueryableValues(values),
        e => e.Id,
        v => v,
        (e, v) => new
        {
            e.Id,
            e.GuidValue
        }
    )
    .ToList();

// Example #2 (LINQ query syntax)
var myQuery2 = (
    from e in dbContext.TestData
    join v in dbContext.AsQueryableValues(values) on e.Id equals v
    select new
    {
        e.Id,
        e.GuidValue
    })
    .ToList();

You can combine multiple set of values in a query:

// Sample values.
IEnumerable<int> values1 = Enumerable.Range(1, 5);
IEnumerable<int> values2 = Enumerable.Range(5, 5);

var qvQuery1 = dbContext.AsQueryableValues(values1);
var qvQuery2 = dbContext.AsQueryableValues(values2);

var myQuery = (
    from e in dbContext.TestData
    where
        qvQuery1.Contains(e.Id) ||
        qvQuery2.Contains(e.Id)
    select new
    {
        e.Id,
        e.GuidValue
    })
    .ToList();

You can mix and match these strategies in your query and make them as complex as you like.

That's it!

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Thanks! 🖖🙂