{"id":9804,"date":"2019-05-10T10:00:55","date_gmt":"2019-05-10T04:30:55","guid":{"rendered":"http:\/\/innoroo.com\/blog\/?p=9804"},"modified":"2019-05-06T16:12:59","modified_gmt":"2019-05-06T10:42:59","slug":"command-query-separation-glossary","status":"publish","type":"post","link":"https:\/\/innoroo.com\/blog\/2019\/05\/10\/command-query-separation-glossary\/","title":{"rendered":"Command query separation | Glossary"},"content":{"rendered":"\n<p><strong>Definition: <\/strong><br><\/p>\n\n\n\n<p>Bertrand Meyer devised CQS, or Command Query Separation, as part of his work on the Eiffel programming language.<\/p>\n\n\n\n<p>The fundamental idea is that we should divide an object&#8217;s methods into two sharply separated categories:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>Queries<\/strong>: Return a result and do not change the observable state of the system (are free of side effects).<\/li><li><strong>Commands<\/strong>: Change the state of a system but do not return a value.<\/li><\/ul>\n\n\n\n<p><strong>Further Reading: <\/strong><\/p>\n\n\n\n<p><strong>Book: Applying UML and Patterns by Craig Larman<\/strong><br><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Definition: Bertrand Meyer devised CQS, or Command Query Separation, as part of his work on the Eiffel programming language. The fundamental idea is that we should divide an object&#8217;s methods into two sharply separated categories: Queries: Return a result and do not change the observable state of the system (are free of side effects). Commands: [&hellip;]<\/p>\n","protected":false},"author":13,"featured_media":9805,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false},"version":2}},"categories":[102],"tags":[2475],"class_list":["post-9804","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-glossary","tag-command-query-separation"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/innoroo.com\/blog\/wp-content\/uploads\/2019\/05\/Command-query-separation-01.png?fit=750%2C410&ssl=1","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p8Rui8-2y8","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/innoroo.com\/blog\/wp-json\/wp\/v2\/posts\/9804","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innoroo.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/innoroo.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/innoroo.com\/blog\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/innoroo.com\/blog\/wp-json\/wp\/v2\/comments?post=9804"}],"version-history":[{"count":1,"href":"https:\/\/innoroo.com\/blog\/wp-json\/wp\/v2\/posts\/9804\/revisions"}],"predecessor-version":[{"id":9806,"href":"https:\/\/innoroo.com\/blog\/wp-json\/wp\/v2\/posts\/9804\/revisions\/9806"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/innoroo.com\/blog\/wp-json\/wp\/v2\/media\/9805"}],"wp:attachment":[{"href":"https:\/\/innoroo.com\/blog\/wp-json\/wp\/v2\/media?parent=9804"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/innoroo.com\/blog\/wp-json\/wp\/v2\/categories?post=9804"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/innoroo.com\/blog\/wp-json\/wp\/v2\/tags?post=9804"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}