{"id":4014,"date":"2023-03-02T18:06:34","date_gmt":"2023-03-02T23:06:34","guid":{"rendered":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/?p=4014"},"modified":"2023-03-02T18:06:34","modified_gmt":"2023-03-02T23:06:34","slug":"2a-erds","status":"publish","type":"post","link":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/2023\/03\/02\/2a-erds\/","title":{"rendered":"2a: ERDs"},"content":{"rendered":"<p><span style=\"font-weight: 400;font-size: 10pt\">An Entity Relationship Diagram is a visual representation of the relationship between entities in a process and creates a structured database. They can be used to document existing databases, develop new ones, or identify any issues within those that already exist. Being able to interpret the steps in a system in different ways allows for a greater understanding of the operations.<\/span><\/p>\n<p><span style=\"font-weight: 400;font-size: 10pt\">There are two types of ERD notations:<\/span><\/p>\n<p><span style=\"font-weight: 400;font-size: 10pt\">Chen\u2019s notation \u2192 this notation is visually similar to swimlanes in its\u2019 use of shapes to create a diagram. Entities are indicted by rectangles and represent a noun. Circles are used to describe the attributes of an entity (adjectives or characteristics). Diamonds are used to describe the relationship between symbols (verb).<\/span><\/p>\n<p><span style=\"font-size: 10pt\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-4015 alignright\" src=\"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/files\/2023\/03\/erd-1-300x171.png\" alt=\"\" width=\"300\" height=\"171\" srcset=\"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/files\/2023\/03\/erd-1-300x171.png 300w, https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/files\/2023\/03\/erd-1-768x438.png 768w, https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/files\/2023\/03\/erd-1.png 999w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/span><\/p>\n<p><span style=\"font-size: 10pt\"><span style=\"font-weight: 400\">Crow\u2019s Foot notation \u2192 this notation creates a box for each entity, then <\/span><span style=\"font-weight: 400\">lists the attributes below in the same box. Entities contain a unique identifier called the primary key (PK) that cannot be shared between multiple values. Relationships can be one-to-one, one-to-many, or many-to-many, and is determined by whether there is a crow\u2019s foot represented at the end of the connectors.<\/span><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>An Entity Relationship Diagram is a visual representation of the relationship between entities in a process and creates a structured database. They can be used to document existing databases, develop new ones, or identify any issues within those that already exist. Being able to interpret the steps in a system in different ways allows for [&hellip;]<\/p>\n","protected":false},"author":29253,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[663943],"tags":[],"class_list":{"0":"post-4014","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-instructor","7":"entry"},"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/wp-json\/wp\/v2\/posts\/4014","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/wp-json\/wp\/v2\/users\/29253"}],"replies":[{"embeddable":true,"href":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/wp-json\/wp\/v2\/comments?post=4014"}],"version-history":[{"count":1,"href":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/wp-json\/wp\/v2\/posts\/4014\/revisions"}],"predecessor-version":[{"id":4016,"href":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/wp-json\/wp\/v2\/posts\/4014\/revisions\/4016"}],"wp:attachment":[{"href":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/wp-json\/wp\/v2\/media?parent=4014"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/wp-json\/wp\/v2\/categories?post=4014"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/community.mis.temple.edu\/mis2101sec730spring2023\/wp-json\/wp\/v2\/tags?post=4014"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}