--- title: EF Core Union Types: A Practical Guide | daily.dev description: A practical walkthrough of persisting C# union types (coming in C# 15) with EF Core, which natively cannot handle value-typed union types as entities. The... canonical: https://daily.dev/posts/ef-core-union-types-a-practical-guide-l6bkq4jyy twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: EF Core Union Types: A Practical Guide | daily.dev og:description: A practical walkthrough of persisting C# union types (coming in C# 15) with EF Core, which natively cannot handle value-typed union types as entities. The... og:url: https://daily.dev/posts/ef-core-union-types-a-practical-guide-l6bkq4jyy og:image: https://api.daily.dev/og/posts/L6BKq4Jyy.png og:image:alt: EF Core Union Types: A Practical Guide og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # EF Core Union Types: A Practical Guide **[Zoran Horvat](https://daily.dev/sources/zoranhorvat)** · 12 min read · 2 upvotes · 0 comments ## Summary A practical walkthrough of persisting C# union types (coming in C# 15) with EF Core, which natively cannot handle value-typed union types as entities. The approach introduces a companion data model record that flattens all possible union variant fields into nullable columns on the containing entity's table, using a hardcoded string discriminator. EF Core maps this via ComplexProperty on a private backing field, while explicit two-way conversion methods bridge the rich domain model and the flat relational representation. The result lets application code work entirely with the union type while EF Core transparently handles persistence. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Working union types into C\#](https://daily.dev/posts/working-union-types-into-c--n1rhxnbqf) · Atomic Spin · 0 upvotes · 0 comments --- Tags: [#c#](https://daily.dev/tags/c#) [View this post on daily.dev](https://daily.dev/posts/ef-core-union-types-a-practical-guide-l6bkq4jyy) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"EF Core Union Types: A Practical Guide","url":"https://daily.dev/posts/ef-core-union-types-a-practical-guide-l6bkq4jyy","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/ef-core-union-types-a-practical-guide-l6bkq4jyy"},"datePublished":"2026-07-14T06:35:41.503Z","dateModified":"2026-07-14T06:35:59.832Z","description":"A practical walkthrough of persisting C# union types (coming in C# 15) with EF Core, which natively cannot handle value-typed union types as entities. 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