{"id":496,"date":"2022-08-23T17:46:55","date_gmt":"2022-08-23T16:46:55","guid":{"rendered":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/?page_id=496"},"modified":"2022-08-23T18:36:03","modified_gmt":"2022-08-23T17:36:03","slug":"entity-relational-diagrams","status":"publish","type":"page","link":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/entity-relational-diagrams\/","title":{"rendered":"Entity Relational Diagrams"},"content":{"rendered":"<p>An entity-relationship diagram is a graphical representation of the entities (tables) in a database. It is used to illustrate the relationship that exists between two or more entities.<\/p>\n<p><a href=\"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23175735\/erd.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-498\" src=\"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23175735\/erd.png\" alt=\"\" width=\"575\" height=\"205\" srcset=\"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23175735\/erd.png 1084w, https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23175735\/erd-300x107.png 300w, https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23175735\/erd-1024x365.png 1024w, https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23175735\/erd-768x273.png 768w, https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23175735\/erd-624x222.png 624w\" sizes=\"auto, (max-width: 575px) 100vw, 575px\" \/><\/a><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>Below is an illustration of a Entity Relational Diagram (ERD) with the Entities and their attributes<\/p>\n<p><a href=\"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23182855\/ERD1.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-500\" src=\"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23182855\/ERD1.png\" alt=\"\" width=\"1260\" height=\"499\" srcset=\"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23182855\/ERD1.png 1260w, https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23182855\/ERD1-300x119.png 300w, https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23182855\/ERD1-1024x406.png 1024w, https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23182855\/ERD1-768x304.png 768w, https:\/\/blogs.glowscotland.org.uk\/glowblogs\/public\/phsn5computingscience\/uploads\/sites\/10033\/2022\/08\/23182855\/ERD1-624x247.png 624w\" sizes=\"auto, (max-width: 1260px) 100vw, 1260px\" \/><\/a><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><span style=\"color: #ff0000\"><strong>One Course teaches many pupils<\/strong><\/span><\/p>\n<ul>\n<li>The <strong>Primary Keys<\/strong> in both tables must be <u>underline<\/u><\/li>\n<li>The <strong>Foreign Key<\/strong> in the many table must have an asterisks *<\/li>\n<li>The side of the ERD that has the<strong> Foreign Key<\/strong> will be the many side and will be illustrated with the crows feet<\/li>\n<li>The relationship must always be described (teaches)<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>An entity-relationship diagram is a graphical representation of the entities (tables) in a database. It is used to illustrate the relationship that exists between two or more entities. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Below is an illustration of a Entity Relational Diagram (ERD) with the Entities and their attributes &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; [&hellip;]<\/p>\n","protected":false},"author":79984,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-496","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/pages\/496","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/users\/79984"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/comments?post=496"}],"version-history":[{"count":3,"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/pages\/496\/revisions"}],"predecessor-version":[{"id":501,"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/pages\/496\/revisions\/501"}],"wp:attachment":[{"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/media?parent=496"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}