--- title: What if I told you that Relational Databases are in fact... description: Relational databases internally use a concept called Write-Ahead Log (WAL) or Transaction Log, which closely mirrors Event Sourcing. In WAL, every database... canonical: https://daily.dev/posts/what-if-i-told-you-that-relational-databases-are-in-fact-event-stores--7enmkono9 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: What if I told you that Relational Databases are in fact Event Stores? | daily.dev og:description: Relational databases internally use a concept called Write-Ahead Log (WAL) or Transaction Log, which closely mirrors Event Sourcing. In WAL, every database... og:url: https://daily.dev/posts/what-if-i-told-you-that-relational-databases-are-in-fact-event-stores--7enmkono9 og:image: https://api.daily.dev/og/posts/7eNMKoNO9.png og:image:alt: What if I told you that Relational Databases are in fact Event Stores? 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. # What if I told you that Relational Databases are in fact Event Stores? **[Event-Driven by Oskar Dudycz](https://daily.dev/sources/event-driven-io)** · 3 min read · 0 upvotes · 0 comments ## Summary Relational databases internally use a concept called Write-Ahead Log (WAL) or Transaction Log, which closely mirrors Event Sourcing. In WAL, every database operation is appended sequentially to a log before being applied to tables and indexes — making the log the source of truth, just like an event store. Tables act as read models (projections) rebuilt from the log. The key difference is that WAL is closer to 'Command Sourcing' (recording intentions rather than facts) and is purged after changes are applied, whereas event stores retain data long-term. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Building a Resilient Data Platform with Write-Ahead Log at Netflix](https://daily.dev/posts/building-a-resilient-data-platform-with-write-ahead-log-at-netflix-dsy5fjhgt) · Netflix TechBlog · 89 upvotes · 0 comments --- Tags: [#architecture](https://daily.dev/tags/architecture), [#backend](https://daily.dev/tags/backend) [View this post on daily.dev](https://daily.dev/posts/what-if-i-told-you-that-relational-databases-are-in-fact-event-stores--7enmkono9) ```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":"What if I told you that Relational Databases are in fact Event Stores?","url":"https://daily.dev/posts/what-if-i-told-you-that-relational-databases-are-in-fact-event-stores--7enmkono9","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/what-if-i-told-you-that-relational-databases-are-in-fact-event-stores--7enmkono9"},"datePublished":"2026-06-17T11:26:23.090Z","dateModified":"2026-06-17T11:32:26.674Z","description":"Relational databases internally use a concept called Write-Ahead Log (WAL) or Transaction Log, which closely mirrors Event Sourcing. In WAL, every database...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/e6d2fe679ead677d2881731ad817db53?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/e6d2fe679ead677d2881731ad817db53?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Event-Driven by Oskar Dudycz","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Event-Driven by Oskar Dudycz","logo":"https://media.daily.dev/image/upload/s--unDKCFQ0--/f_auto,q_auto/v1781695550/logos/event-driven-io?_a=BAMAMiWQ0","url":"https://daily.dev/sources/event-driven-io"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/what-if-i-told-you-that-relational-databases-are-in-fact-event-stores--7enmkono9","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"architecture,backend","timeRequired":"PT3M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Event-Driven by Oskar Dudycz","item":"https://daily.dev/sources/event-driven-io"},{"@type":"ListItem","position":3,"name":"What if I told you that Relational Databases are in fact Event Stores?"}]} ```