![]() ![]() In the former example, this will be rewritten to: (user != null ? user.Location != null ? user.Location?.AddressLine 1 + (user != null ? user.Location != null ? 2 : null) : null) This will rewrite your expression to explicitly check for nullables. You can configure your projectable as such: If you are dealing with CosmosDB (which may result to client-side evaluation) or want to be explicit about things. This is perfect for a database like SQL Server where nullability is implicit and if any of the arguments were to be null, the resulting value will be null. Which will simply generate an expression tree that ignores the null-conditional operator. Starting from the official release of V2, we can now hint the generator in how to translate this arrow function to an expression tree. This Project will generate an error by default and suggest 2 solutions: Either you rewrite the function to explicitly check for nullables or you let the generator do that for you! This is a perfectly valid arrow function but it can't be translated directly to an expression tree. ![]() Public static string? GetFullAddress(this User? user) => user?.Location?.AddressLine1 + " " + user?.Location.AddressLine2 One obvious limitation is the null-conditional operator. Expressions can only express a subset of valid CSharp statements that are allowed in lambda's and arrow functions. How do I deal with nullable propertiesĮxpressions and Lamdas are different and not equal. Public static int Squared(this int i) => i * i Īny call to squared given any int will perfectly translate to SQL. It's perfectly acceptable to have the following code: Can I use projectable extensions methods on non-entity types? Yes you can! Any projectable property/method can call into other properties and methods as long as those properties/methods are native to EFCore or as long as they are marked with a Projectable attribute. Can I call additional properties and methods from my Projectable properties and methods? With Limited compatibility you will likely see increased performance over EFCore without projectables. The expanded query will then be stored in the Query Cache. Limited compatibility mode is smart about things and only expands the Query after it has been accepted by EF. Because of this additional step, there is a small performance impact. (This is similar to how LinqKit/LinqExpander/Expressionify works). With Full compatibility mode, Each Query will first be expanded (Any calls to Projectable properties and methods will be replaced by their respective Expression) before being handed off to EFCore. Most of the time, limited compatibility mode is sufficient however if you are running into issues with failed query compilation, then you may want to stick with Full compatibility mode. There are 2 compatibility modes: Limited and Full (Default). Are there performance implications that I should be aware of? Of course you're still limited to whatever your database provider can do. No The runtime component injects itself within the EFCore query compilation pipeline and thus has no impact on the database provider used. Each method name needs to be unique within a given type. There is currently no support for overloaded methods. FAQ Are there currently any known limitations? We then have a runtime component that intercepts any query and translates any call to a property or method marked with the Projectable attribute and translates the query to use the generated Expression instead. How it worksĮssentially there are 2 components: We have a source generator that is able to write companion Expression for properties and methods marked with the Projectable attribute. = properties and methods have been inlined! the generated SQL could be improved but this is what EFCore (v5) gives us. The following query gets generated (assuming SQL Server as a database provider) DECLARE nvarchar(4000) = N'Jon' X.GetMostRecentOrderForUser((-30)).GrandTotal Where(x => cutoffDate = null || x.CreatedDate >= cutoffDate) Public static Order GetMostRecentOrderForUser(this User user, DateTime? cutoffDate) => ![]() public decimal GrandTotal => Subtotal + Tax ![]() public decimal Tax => Subtotal * TaxRate public decimal Subtotal => Items.Sum(item => * item.Quantity) View our samples and checkout our Blog Post.Implement projectable properties and methods and mark them with the attribute.Enable Projectables in your DbContext by calling: dbContextOptions.UseProjectables().If you're targeting EF Core 5 or EF Core 3.1 then you can use the latest v1 release. Starting with V2 of this project we're binding against EF Core 6. ![]()
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