| <!DOCTYPE html> |
| <html lang="en"> |
| <head> |
| <meta charset="utf-8"> |
| <meta name="viewport" content="width=device-width,initial-scale=1.0"> |
| <title>Logical data modeling | Apache Cassandra Documentation</title> |
| <link rel="stylesheet" href="../../../../../assets/css/site.css"> |
| <link rel="schema.dcterms" href="https://purl.org/dc/terms/"> |
| <meta name="dcterms.subject" content="Cassandra"> |
| <meta name="dcterms.identifier" content="5.0"> |
| <meta name="generator" content="Antora 2.3.4"> |
| <link rel="icon" href="../../../../../assets/img/favicon.ico" type="image/x-icon"> |
| <script> |
| const script = document.createElement("script"); |
| const domain = window.location.hostname; |
| script.type = "text/javascript"; |
| script.src = "https://plausible.cassandra.apache.org/js/plausible.js"; |
| script.setAttribute("data-domain",domain); |
| script.setAttribute("defer",'true'); |
| script.setAttribute("async",'true'); |
| document.getElementsByTagName("head")[0].appendChild(script); |
| </script> </head> |
| <body class="docs-wrapper article"> |
| <div class="container mx-auto relative"> |
| <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script> |
| <meta property="og:type" content="website" /> |
| <meta property="og:url" content="/" /> |
| <meta property="og:site_name" content="Apache Cassandra" /> |
| |
| <header id="top-nav"> |
| <div class="inner relative"> |
| <div class="header-social-icons text-right"> |
| <a href="https://twitter.com/cassandra?lang=en" target="_blank" styles="margin-left: 20px;"><img src="../../../../../assets/img/twitter-icon-circle-white.svg" alt="twitter icon" width="24"></a> |
| <a href="https://www.linkedin.com/company/apache-cassandra/" target="_blank" styles="margin-left: 20px;"><img src="../../../../../assets/img/LI-In-Bug.png" alt="linked-in icon" width="24"></a> |
| <a href="https://www.youtube.com/c/PlanetCassandra" target="_blank" styles="margin-left: 20px;"><img src="../../../../../assets/img/youtube-icon.png" alt="youtube icon" width="24"></a> |
| </div> |
| <div class="cf"> |
| <div class="logo left"><a href="/"><img src="../../../../../assets/img/logo-white-r.png" alt="Cassandra Logo"></a></div> |
| <div class="mobile-nav-icon right"> |
| <img class="toggle-icon" src="../../../../../assets/img/hamburger-nav.svg"> |
| </div> |
| <ul class="main-nav nav-links right flex flex-vert-center flex-space-between"> |
| <li> |
| <a class="nav-link hide-mobile">Get Started</a> |
| <ul class="sub-menu bg-white"> |
| <li class="pa-micro"> |
| <a href="/_/cassandra-basics.html"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-basics.png" alt="cassandra basics icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Cassandra Basics |
| </div> |
| </a> |
| </li> |
| <li class="pa-micro"> |
| <a href="/_/quickstart.html"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-rocket.png" alt="cassandra basics icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Quickstart |
| </div> |
| </a> |
| </li> |
| <li class="pa-micro"> |
| <a href="/_/ecosystem.html"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-ecosystem.png" alt="cassandra basics icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Ecosystem |
| </div> |
| </a> |
| </li> |
| </ul> |
| </li> |
| <li><a class="nav-link" href="/doc/latest/">Documentation</a></li> |
| <li> |
| <a class="nav-link" href="/_/community.html">Community</a> |
| <ul class="sub-menu bg-white"> |
| <li class="pa-micro"> |
| <a href="/_/community.html#code-of-conduct"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-welcome.png" alt="welcome icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Welcome |
| </div> |
| </a> |
| </li> |
| <li class="pa-micro hide-mobile"> |
| <a href="/_/community.html#discussions"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-discussions.png" alt="discussions icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Discussions |
| </div> |
| </a> |
| </li> |
| <li class="pa-micro hide-mobile"> |
| <a href="/_/community.html#project-governance"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-governance.png" alt="Governance icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Governance |
| </div> |
| </a> |
| </li> |
| <li class="pa-micro hide-mobile"> |
| <a href="/_/community.html#how-to-contribute"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-contribute.png" alt="Contribute icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Contribute |
| </div> |
| </a> |
| </li> |
| <li class="pa-micro hide-mobile"> |
| <a href="/_/community.html#meet-the-community"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-community.png" alt="Meet the Community icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Meet the Community |
| </div> |
| </a> |
| </li> |
| <li class="pa-micro hide-mobile"> |
| <a href="/_/cassandra-catalyst-program.html"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-catalyst.png" alt="Catalyst icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Catalyst Program |
| </div> |
| </a> |
| </li> |
| <li class="pa-micro hide-mobile"> |
| <a href="/_/events.html"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-events.png" alt="Events icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Events |
| </div> |
| </a> |
| </li> |
| </ul> |
| </li> |
| <li> |
| <a class="nav-link hide-mobile">Learn</a> |
| <ul class="sub-menu bg-white"> |
| <li class="pa-micro"> |
| <a href="/_/Apache-Cassandra-5.0-Moving-Toward-an-AI-Driven-Future.html"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-basics.png" alt="Basics icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Cassandra 5.0 |
| </div> |
| </a> |
| </li> |
| <li class="pa-micro"> |
| <a href="/_/case-studies.html"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-case-study.png" alt="Case Studies icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Case Studies |
| </div> |
| </a> |
| </li> |
| <li class="pa-micro"> |
| <a href="/_/resources.html"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-resources.png" alt="Resources icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Resources |
| </div> |
| </a> |
| </li> |
| <li class="pa-micro"> |
| <a href="/_/blog.html"> |
| <div class="sub-nav-icon"> |
| <img src="../../../../../assets/img/sub-menu-blog.png" alt="Blog icon"> |
| </div> |
| <div class="sub-nav-text teal py-small"> |
| Blog |
| </div> |
| </a> |
| </li> |
| </ul> |
| </li> |
| <li><a class="nav-link btn btn--filled" href="/_/download.html">Download Now</a></li> |
| </ul> |
| </div> |
| </div> |
| </header> |
| |
| <div class="hero hero--home grad"> |
| <div class="eye"></div> |
| <div id="docs-content" class="text-center flex flex-center flex-column relative z2 ma-xlarge"> |
| <h2>Cassandra Documentation</h2> |
| </div> |
| </div> |
| <div class="body px-medium py-medium container"> |
| <div class="docs-nav-bar flex flex-space-between mb-medium"> |
| <div id="mobile-docs-nav-burger" class="hidden"> |
| <svg viewBox="0 0 24 24" width="36" height="36" stroke="#1c81a0" stroke-width="2.5" fill="none" stroke-linecap="round" stroke-linejoin="round" class="css-i6dzq1"><line x1="3" y1="12" x2="21" y2="12"></line><line x1="3" y1="6" x2="21" y2="6"></line><line x1="3" y1="18" x2="21" y2="18"></line></svg> |
| </div> |
| <div class="docs-nav-item relative"> |
| <input id="search-input" type="text" placeholder="Search docs"> |
| </div> |
| <div class="versions-wrapper"> |
| <h4>Version:</h4> |
| <div class="nav-panel-explore" data-panel="explore"> |
| |
| <div id="version-toggle" class="context"> |
| <span class="version">5.0</span> |
| </div> |
| <ul id="versions-list" class="components"> |
| <li class="component"> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../../../_/index.html">master</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component is-current"> |
| <ul class="versions"> |
| <li class="version"> |
| <a href="../../../../trunk/index.html">trunk</a> |
| </li> |
| <li class="version is-current"> |
| <a href="../../../index.html">5.0</a> |
| </li> |
| <li class="version is-latest"> |
| <a href="../../../../4.1/index.html">4.1</a> |
| </li> |
| <li class="version"> |
| <a href="../../../../4.0/index.html">4.0</a> |
| </li> |
| <li class="version"> |
| <a href="../../../../3.11/index.html">3.11</a> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </div> |
| </div> </div> |
| <div class="cf relative"> |
| <nav class="nav docs-nav full-800"> |
| <div class="nav-menu"> |
| <ul class="nav-list"> |
| <li class="nav-item is-active" data-depth="0"> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="1"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../../index.html">Main</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/glossary.html">Glossary</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/bugs.html">How to report bugs</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/contactus.html">Contact us</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../../../../_/development/index.html">Development</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/development/gettingstarted.html">Getting started</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/development/ide.html">Building and IDE integration</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/development/testing.html">Testing</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/development/patches.html">Contributing code changes</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/development/code_style.html">Code style</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/development/how_to_review.html">Review checklist</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/development/how_to_commit.html">How to commit</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/development/documentation.html">Working on documentation</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/development/ci.html">Jenkins CI environment</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/development/dependencies.html">Dependency management</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../../../../_/development/release_process.html">Release process</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item is-active" data-depth="0"> |
| <ul class="nav-list"> |
| <li class="nav-item is-current-path is-active" data-depth="1"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <span class="nav-text">Cassandra</span> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../overview/faq/index.html">FAQ</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../getting-started/index.html">Getting Started</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../getting-started/cassandra-quickstart.html">Cassandra Quickstart</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../getting-started/sai-quickstart.html">SAI Quickstart</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../getting-started/vector-search-quickstart.html">Vector Search Quickstart</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../installing/installing.html">Installing Cassandra</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../getting-started/configuring.html">Configuring Cassandra</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../getting-started/querying.html">Inserting and querying</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../getting-started/drivers.html">Client drivers</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../getting-started/production.html">Production recommendations</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../new/index.html">What’s new</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../reference/java17.html">Support for Java</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../architecture/index.html">Architecture</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../architecture/overview.html">Overview</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../architecture/dynamo.html">Dynamo</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../architecture/storage-engine.html">Storage Engine</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../architecture/guarantees.html">Guarantees</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../architecture/messaging.html">Improved Internode Messaging</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../architecture/streaming.html">Improved Streaming</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item is-current-path is-active" data-depth="2"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="index.html">Data Modeling</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="intro.html">Introduction</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="data-modeling_conceptual.html">Conceptual data modeling</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="data-modeling_rdbms.html">RDBMS design</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="data-modeling_queries.html">Defining application queries</a> |
| </span> |
| </li> |
| <li class="nav-item is-current-page is-active" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="data-modeling_logical.html">Logical data modeling</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="data-modeling_physical.html">Physical data modeling</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="data-modeling_refining.html">Evaluating and refining data models</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="data-modeling_schema.html">Defining database schema</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="data-modeling_tools.html">Cassandra data modeling tools</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../cql/index.html">Cassandra Query Language (CQL)</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/definitions.html">Definitions</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/types.html">Data types</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/ddl.html">Data definition (DDL)</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/dml.html">Data manipulation (DML)</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/dynamic-data-masking.html">Dynamic Data Masking (DDM)</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/operators.html">Operators</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../cql/indexing/indexing-concepts.html">Indexing concepts</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../cql/indexing/sai/sai-overview.html">SAI Overview</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="5"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/indexing/sai/sai-concepts.html">Concepts</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="5"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../getting-started/sai-quickstart.html">SAI Quickstart</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="5"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/indexing/sai/sai-faq.html">SAI FAQ</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="5"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/indexing/sai/sai-working-with.html">Working with SAI</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="5"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/indexing/sai/operations/sai-operations.html">SAI operations</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../cql/indexing/2i/2i-overview.html">Secondary indexes (2i) overview</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="5"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/indexing/2i/2i-concepts.html">Concepts</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="5"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/indexing/2i/2i-working-with.html">Working with 2i</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="5"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/indexing/2i/operations/2i-build.html">Rebuild 2i</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/mvs.html">Materialized views</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/functions.html">Functions</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/json.html">JSON</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/security.html">Security</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/triggers.html">Triggers</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/appendices.html">Appendices</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/changes.html">Changes</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/SASI.html">SASI</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../cql/cql_singlefile.html">Single file of CQL information</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../vector-search/overview.html">Vector Search overview</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../vector-search/concepts.html">Concepts</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../vector-search/data-modeling.html">Data Modeling</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../getting-started/vector-search-quickstart.html">Vector Search Quickstart</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../vector-search/vector-search-working-with.html">Working with Vector Search</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../managing/index.html">Managing</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../managing/configuration/index.html">Configuring</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/configuration/cass_yaml_file.html">cassandra.yaml</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/configuration/cass_rackdc_file.html">cassandra-rackdc.properties</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/configuration/cass_env_sh_file.html">cassandra-env.sh</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/configuration/cass_topo_file.html">cassandra-topologies.properties</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/configuration/cass_cl_archive_file.html">commitlog-archiving.properties</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/configuration/cass_logback_xml_file.html">logback.xml</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/configuration/cass_jvm_options_file.html">jvm-* files</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/configuration/configuration.html">Liberating cassandra.yaml Parameters' Names from Their Units</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../managing/operating/index.html">Operating</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/backups.html">Backups</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/bloom_filters.html">Bloom filters</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/bulk_loading.html">Bulk loading</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/cdc.html">Change Data Capture (CDC)</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/compaction/index.html">Compaction</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/compression.html">Compression</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/hardware.html">Hardware</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/hints.html">Hints</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../managing/operating/logging.html">Logging</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="5"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/auditlogging.html">Audit logging</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="5"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/audit_logging.html">Audit logging 2</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="5"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/fqllogging.html">Full query logging</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/metrics.html">Monitoring metrics</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/repair.html">Repair</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/read_repair.html">Read repair</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/security.html">Security</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/snitch.html">Snitches</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/topo_changes.html">Topology changes</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/transientreplication.html">Transient replication</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/operating/virtualtables.html">Virtual tables</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../managing/tools/index.html">Tools</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/tools/cqlsh.html">cqlsh: the CQL shell</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/tools/nodetool/nodetool.html">nodetool</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../managing/tools/sstable/index.html">SSTable tools</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <span class="nav-line"> |
| <a class="nav-link" href="#cassandra:managing/tools/cassandra_stress.adoc">cassandra-stress</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../troubleshooting/index.html">Troubleshooting</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../troubleshooting/finding_nodes.html">Finding misbehaving nodes</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../troubleshooting/reading_logs.html">Reading Cassandra logs</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../troubleshooting/use_nodetool.html">Using nodetool</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../troubleshooting/use_tools.html">Using external tools to deep-dive</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <button class="nav-toggle"></button> |
| <a class="nav-link" href="../../reference/index.html">Reference</a> |
| </span> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../reference/cql-commands/alter-table.html">ALTER TABLE</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../reference/cql-commands/create-index.html">CREATE INDEX</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../reference/cql-commands/create-custom-index.html">CREATE CUSTOM INDEX</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../reference/cql-commands/create-table.html">CREATE TABLE</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../reference/cql-commands/drop-index.html">DROP INDEX</a> |
| </span> |
| </li> |
| <li class="nav-item" data-depth="3"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../reference/cql-commands/drop-table.html">DROP TABLE</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <span class="nav-line"> |
| <a class="nav-link" href="../../integrating/plugins/index.html">Plug-ins</a> |
| </span> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </div> |
| </nav> |
| <aside class="toc sidebar"> |
| <div class="toc-menu"></div> |
| </aside> |
| <main class="article default-main full-800" data-ceiling="topbar"> |
| <div class="article-banner"> |
| <p>You are viewing the documentation for a prerelease version.</p> |
| </div> |
| <div class="article-header"> |
| <nav class="crumbs" aria-label="breadcrumbs"> |
| <ul> |
| <li class="crumb">Cassandra</li> |
| <li class="crumb"><a href="index.html">Data Modeling</a></li> |
| <li class="crumb"><a href="data-modeling_logical.html">Logical data modeling</a></li> |
| </ul> |
| </nav> |
| <div class="tools" role="navigation"> |
| <ul> |
| <li class="tool edit"><a href="https://github.com/apache/cassandra/edit/cassandra-5.0/doc/modules/cassandra/pages/developing/data-modeling/data-modeling_logical.adoc" title="Edit Page" target="_blank" rel="noopener">Edit</a></li> |
| </ul> |
| </div> |
| </div> |
| <article class="doc"> |
| <h1 class="page">Logical data modeling</h1> |
| <div id="preamble"> |
| <div class="sectionbody"> |
| <div class="paragraph"> |
| <p>Now that you have defined your queries, you’re ready to begin designing |
| Cassandra tables. First, create a logical model containing a table for |
| each query, capturing entities and relationships from the conceptual |
| model.</p> |
| </div> |
| <div class="paragraph"> |
| <p>To name each table, you’ll identify the primary entity type for which |
| you are querying and use that to start the entity name. If you are |
| querying by attributes of other related entities, append those to the |
| table name, separated with <code><em>by</em></code>. For example, <code>hotels_by_poi</code>.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Next, you identify the primary key for the table, adding partition key |
| columns based on the required query attributes, and clustering columns |
| in order to guarantee uniqueness and support desired sort ordering.</p> |
| </div> |
| <div class="paragraph"> |
| <p>The design of the primary key is extremely important, as it will |
| determine how much data will be stored in each partition and how that |
| data is organized on disk, which in turn will affect how quickly |
| Cassandra processes reads.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Complete each table by adding any additional attributes identified by |
| the query. If any of these additional attributes are the same for every |
| instance of the partition key, mark the column as static.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Now that was a pretty quick description of a fairly involved process, so |
| it will be worthwhile to work through a detailed example. First, let’s |
| introduce a notation that you can use to represent logical models.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Several individuals within the Cassandra community have proposed |
| notations for capturing data models in diagrammatic form. This document |
| uses a notation popularized by Artem Chebotko which provides a simple, |
| informative way to visualize the relationships between queries and |
| tables in your designs. This figure shows the Chebotko notation for a |
| logical data model.</p> |
| </div> |
| <div class="imageblock"> |
| <div class="content"> |
| <img src="cassandra:developing/data-modeling/data-modeling_chebotko_logical.png" alt="image"> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>Each table is shown with its title and a list of columns. Primary key |
| columns are identified via symbols such as <strong>K</strong> for partition key columns |
| and <strong>C</strong>↑ or <strong>C</strong>↓ to represent clustering columns. Lines are shown |
| entering tables or between tables to indicate the queries that each |
| table is designed to support.</p> |
| </div> |
| </div> |
| </div> |
| <div class="sect1"> |
| <h2 id="hotel-logical-data-model"><a class="anchor" href="#hotel-logical-data-model"></a>Hotel Logical Data Model</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"> |
| <p>The figure below shows a Chebotko logical data model for the queries |
| involving hotels, points of interest, rooms, and amenities. One thing |
| you’ll notice immediately is that the Cassandra design doesn’t include |
| dedicated tables for rooms or amenities, as you had in the relational |
| design. This is because the workflow didn’t identify any queries |
| requiring this direct access.</p> |
| </div> |
| <div class="imageblock"> |
| <div class="content"> |
| <img src="cassandra:developing/data-modeling/data-modeling_hotel_logical.png" alt="image"> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>Let’s explore the details of each of these tables.</p> |
| </div> |
| <div class="paragraph"> |
| <p>The first query Q1 is to find hotels near a point of interest, so you’ll |
| call this table <code>hotels_by_poi</code>. Searching by a named point of interest |
| is a clue that the point of interest should be a part of the primary |
| key. Let’s reference the point of interest by name, because according to |
| the workflow that is how users will start their search.</p> |
| </div> |
| <div class="paragraph"> |
| <p>You’ll note that you certainly could have more than one hotel near a |
| given point of interest, so you’ll need another component in the primary |
| key in order to make sure you have a unique partition for each hotel. So |
| you add the hotel key as a clustering column.</p> |
| </div> |
| <div class="paragraph"> |
| <p>An important consideration in designing your table’s primary key is |
| making sure that it defines a unique data element. Otherwise you run the |
| risk of accidentally overwriting data.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Now for the second query (Q2), you’ll need a table to get information |
| about a specific hotel. One approach would have been to put all of the |
| attributes of a hotel in the <code>hotels_by_poi</code> table, but you added only |
| those attributes that were required by the application workflow.</p> |
| </div> |
| <div class="paragraph"> |
| <p>From the workflow diagram, you know that the <code>hotels_by_poi</code> table is |
| used to display a list of hotels with basic information on each hotel, |
| and the application knows the unique identifiers of the hotels returned. |
| When the user selects a hotel to view details, you can then use Q2, |
| which is used to obtain details about the hotel. Because you already |
| have the <code>hotel_id</code> from Q1, you use that as a reference to the hotel |
| you’re looking for. Therefore the second table is just called <code>hotels</code>.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Another option would have been to store a set of <code>poi_names</code> in the |
| hotels table. This is an equally valid approach. You’ll learn through |
| experience which approach is best for your application.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Q3 is just a reverse of Q1—looking for points of interest near a hotel, |
| rather than hotels near a point of interest. This time, however, you |
| need to access the details of each point of interest, as represented by |
| the <code>pois_by_hotel</code> table. As previously, you add the point of interest |
| name as a clustering key to guarantee uniqueness.</p> |
| </div> |
| <div class="paragraph"> |
| <p>At this point, let’s now consider how to support query Q4 to help the |
| user find available rooms at a selected hotel for the nights they are |
| interested in staying. Note that this query involves both a start date |
| and an end date. Because you’re querying over a range instead of a |
| single date, you know that you’ll need to use the date as a clustering |
| key. Use the <code>hotel_id</code> as a primary key to group room data for each |
| hotel on a single partition, which should help searches be super fast. |
| Let’s call this the <code>available_rooms_by_hotel_date</code> table.</p> |
| </div> |
| <div class="paragraph"> |
| <p>To support searching over a range, use <code>clustering columns |
| <clustering-columns></code> to store attributes that you need to access in a |
| range query. Remember that the order of the clustering columns is |
| important.</p> |
| </div> |
| <div class="paragraph"> |
| <p>The design of the <code>available_rooms_by_hotel_date</code> table is an instance |
| of the <strong>wide partition</strong> pattern. This pattern is sometimes called the |
| <strong>wide row</strong> pattern when discussing databases that support similar |
| models, but wide partition is a more accurate description from a |
| Cassandra perspective. The essence of the pattern is to group multiple |
| related rows in a partition in order to support fast access to multiple |
| rows within the partition in a single query.</p> |
| </div> |
| <div class="paragraph"> |
| <p>In order to round out the shopping portion of the data model, add the |
| <code>amenities_by_room</code> table to support Q5. This will allow users to view |
| the amenities of one of the rooms that is available for the desired stay |
| dates.</p> |
| </div> |
| </div> |
| </div> |
| <div class="sect1"> |
| <h2 id="reservation-logical-data-model"><a class="anchor" href="#reservation-logical-data-model"></a>Reservation Logical Data Model</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"> |
| <p>Now let’s switch gears to look at the reservation queries. The figure |
| shows a logical data model for reservations. You’ll notice that these |
| tables represent a denormalized design; the same data appears in |
| multiple tables, with differing keys.</p> |
| </div> |
| <div class="imageblock"> |
| <div class="content"> |
| <img src="cassandra:developing/data-modeling/data-modeling_reservation_logical.png" alt="image"> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>In order to satisfy Q6, the <code>reservations_by_guest</code> table can be used to |
| look up the reservation by guest name. You could envision query Q7 being |
| used on behalf of a guest on a self-serve website or a call center agent |
| trying to assist the guest. Because the guest name might not be unique, |
| you include the guest ID here as a clustering column as well.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Q8 and Q9 in particular help to remind you to create queries that |
| support various stakeholders of the application, not just customers but |
| staff as well, and perhaps even the analytics team, suppliers, and so |
| on.</p> |
| </div> |
| <div class="paragraph"> |
| <p>The hotel staff might wish to see a record of upcoming reservations by |
| date in order to get insight into how the hotel is performing, such as |
| what dates the hotel is sold out or undersold. Q8 supports the retrieval |
| of reservations for a given hotel by date.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Finally, you create a <code>guests</code> table. This provides a single location |
| that used to store guest information. In this case, you specify a |
| separate unique identifier for guest records, as it is not uncommon for |
| guests to have the same name. In many organizations, a customer database |
| such as the <code>guests</code> table would be part of a separate customer |
| management application, which is why other guest access patterns were |
| omitted from the example.</p> |
| </div> |
| </div> |
| </div> |
| <div class="sect1"> |
| <h2 id="patterns-and-anti-patterns"><a class="anchor" href="#patterns-and-anti-patterns"></a>Patterns and Anti-Patterns</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"> |
| <p>As with other types of software design, there are some well-known |
| patterns and anti-patterns for data modeling in Cassandra. You’ve |
| already used one of the most common patterns in this hotel model—the |
| wide partition pattern.</p> |
| </div> |
| <div class="paragraph"> |
| <p>The <strong>time series</strong> pattern is an extension of the wide partition pattern. |
| In this pattern, a series of measurements at specific time intervals are |
| stored in a wide partition, where the measurement time is used as part |
| of the partition key. This pattern is frequently used in domains |
| including business analysis, sensor data management, and scientific |
| experiments.</p> |
| </div> |
| <div class="paragraph"> |
| <p>The time series pattern is also useful for data other than measurements. |
| Consider the example of a banking application. You could store each |
| customer’s balance in a row, but that might lead to a lot of read and |
| write contention as various customers check their balance or make |
| transactions. You’d probably be tempted to wrap a transaction around |
| writes just to protect the balance from being updated in error. In |
| contrast, a time series–style design would store each transaction as a |
| timestamped row and leave the work of calculating the current balance to |
| the application.</p> |
| </div> |
| <div class="paragraph"> |
| <p>One design trap that many new users fall into is attempting to use |
| Cassandra as a queue. Each item in the queue is stored with a timestamp |
| in a wide partition. Items are appended to the end of the queue and read |
| from the front, being deleted after they are read. This is a design that |
| seems attractive, especially given its apparent similarity to the time |
| series pattern. The problem with this approach is that the deleted items |
| are now <code>tombstones <asynch-deletes></code> that Cassandra must scan past in |
| order to read from the front of the queue. Over time, a growing number |
| of tombstones begins to degrade read performance.</p> |
| </div> |
| <div class="paragraph"> |
| <p>The queue anti-pattern serves as a reminder that any design that relies |
| on the deletion of data is potentially a poorly performing design.</p> |
| </div> |
| <div class="paragraph"> |
| <p><em>Material adapted from Cassandra, The Definitive Guide. Published by |
| O’Reilly Media, Inc. Copyright © 2020 Jeff Carpenter, Eben Hewitt. All |
| rights reserved. Used with permission.</em></p> |
| </div> |
| </div> |
| </div> |
| </article> |
| </main> |
| </div> |
| </div> |
| <footer class="grad grad--two flex-center pb-xlarge"> |
| <div class="inner text-center z2 relative"> |
| <h2 class="white py-small">Get started with Cassandra, fast.</h2> |
| <a id="footer-cta" href="/_/quickstart.html" class="btn btn--filled ma-medium">Quickstart Guide</a> |
| </div> |
| <div class="inner flex flex-distribute-items mt-xlarge z2 relative"> |
| <div class="col-2"> |
| <div id="footer-logo" class="logo logo--footer mb-medium"><img src="../../../../../assets/img/logo-white-r.png" alt="Cassandra Logo"></div> |
| <p>Apache Cassandra<img src="../../../../../assets/img/registered.svg" alt="®" style="width:18px;"> powers mission-critical deployments with improved performance and unparalleled levels of scale in the cloud.</p> |
| <div class="footer-social-icons"> |
| <a href="https://twitter.com/cassandra?lang=en" target="_blank"><img src="../../../../../assets/img/twitter-icon-circle-white.svg" alt="twitter icon" width="24"></a> |
| <a href="https://www.linkedin.com/company/apache-cassandra/" target="_blank"><img src="../../../../../assets/img/LI-In-Bug.png" alt="linked-in icon" width="24"></a> |
| <a href="https://www.youtube.com/c/PlanetCassandra" target="_blank"><img src="../../../../../assets/img/youtube-icon.png" alt="youtube icon" width="24"></a> |
| </div> |
| </div> |
| <div class="col-2 flex flex-center"> |
| <ul class="columns-2"> |
| <li class="mb-small"><a href="/">Home</a></li> |
| <li class="mb-small"><a href="/_/cassandra-basics.html">Cassandra Basics</a></li> |
| <li class="mb-small"><a href="/_/quickstart.html">Quickstart</a></li> |
| <li class="mb-small"><a href="/_/ecosystem.html">Ecosystem</a></li> |
| <li class="mb-small"><a href="/doc/latest/">Documentation</a></li> |
| <li class="mb-small"><a href="/_/community.html">Community</a></li> |
| <li class="mb-small"><a href="/_/case-studies.html">Case Studies</a></li> |
| <li class="mb-small"><a href="/_/resources.html">Resources</a></li> |
| <li class="mb-small"><a href="/_/blog.html">Blog</a></li> |
| </ul> |
| </div> |
| </div> |
| </footer> |
| <div class="lower-footer bg-white pa-medium"> |
| <div class="flex flex-row flex-vert-center"> |
| <div class="pr-medium"><img src="../../../../../assets/img//feather-small.png" alt="ASF" width="20"></div> |
| <div class="pr-medium"><a href="http://www.apache.org/" target="_blank">Foundation</a></div> |
| <div class="pr-medium"><a href="https://www.apache.org/events/current-event.html" target="_blank">Events</a></div> |
| <div class="pr-medium"><a href="https://www.apache.org/licenses/" target="_blank">License</a></div> |
| <div class="pr-medium"><a href="https://www.apache.org/foundation/thanks" target="_blank">Thanks</a></div> |
| <div class="pr-medium"><a href="https://www.apache.org/security" target="_blank">Security</a></div> |
| <div class="pr-medium"><a href="https://privacy.apache.org/policies/privacy-policy-public.html" target="_blank">Privacy</a></div> |
| <div class="pr-medium"><a href="https://www.apache.org/foundation/sponsorship" target="_blank">Sponsorship</a></div> |
| </div> |
| <p class="my-medium">© 2009-<script>document.write(new Date().getFullYear())</script> <a href="https://apache.org" target="_blank">The Apache Software Foundation</a> under the terms of the Apache License 2.0. Apache, the Apache feather logo, Apache Cassandra, Cassandra, and the Cassandra logo, are either registered trademarks or trademarks of The Apache Software Foundation.</p> |
| </div> |
| <div id="fade" class="hidden"></div> |
| <div id="modal" class="hidden"> |
| <div id="close-modal" class="cursor-pointer"><svg viewBox="0 0 24 24" width="24" height="24" stroke="currentColor" stroke-width="2" fill="none" stroke-linecap="round" stroke-linejoin="round" class="css-i6dzq1"><line x1="18" y1="6" x2="6" y2="18"></line><line x1="6" y1="6" x2="18" y2="18"></line></svg></div> |
| <div id="mod-content" class="vid-mod-content resp-container"></div> |
| </div> |
| <script src="../../../../../assets/js/site.js"></script> |
| <script async src="../../../../../assets/js/vendor/highlight.js"></script> |
| <script src="../../../../../assets/js/vendor/lunr.js"></script> |
| <script src="../../../../../assets/js/vendor/search.js" id="search-script" data-base-path="../../../../.." data-page-path="/Cassandra/5.0/cassandra/developing/data-modeling/data-modeling_logical.html"></script> |
| <script async src="../../../../../assets/../search-index.js"></script> |
| <script> |
| jQuery(function(){ |
| var windowW = $(window).width(); |
| $(document) |
| .on('click','.mobile-nav-icon',function(){ |
| $('.main-nav').fadeIn(); |
| }) |
| .on('click','.main-nav',function(){ |
| if(windowW <= 1000){ |
| $(this).fadeOut(); |
| } |
| }) |
| .on('click','#version-toggle',function(){ |
| $(this).toggleClass('active'); |
| $(this).next().fadeToggle(); |
| }) |
| .on('click','#mobile-docs-nav-burger', function(){ |
| $(this).toggleClass('active'); |
| $('.docs-nav').toggleClass('active'); |
| }); |
| var url = window.location.pathname; |
| var isQuickstart = url.includes('quickstart.html'); |
| if(isQuickstart){ |
| var footerCTA = document.getElementById('footer-cta'); |
| footerCTA.innerHTML = 'Get latest updates'; |
| footerCTA.setAttribute('href', '/_/blog.html'); |
| } |
| }); |
| </script> |
| </div> |
| </body> |
| </html> |
