The previous chapter focused on the flow of information and processes, while Chapter 8 of MSAD focused on data requirements. Data models are important because they can serve as the foundation for database design. And since data are often the most complex aspects of information systems, data modeling needs to be comprehensive and accurate. One interesting point I found was that “an information system design based on a data orientation, rather than a process or logic orientation, should have a longer useful life and should have common features for the same applications or domains in different organizations.”<\/p>\n
ERDs, or entity relationship diagrams, are the most common form used for data modeling. Class diagrams are used for object-oriented analysis. You can go about it with either a top-down or bottom-up approach. Top-down comes from an intimate understanding of the nature of the business. Bottom-up comes from reviewing business documents and knowing what data are needed. An entity is a person, place, object, event, or concept about which the organization wishes to maintain data. An entity type (sometimes called an entity class) is a collection of entities that share common properties or characteristics. An entity instance is a single occurrence of an entity type. It’s important to have clear, descriptive names so everyone knows what is being referenced. Thus there are specific entity and attribute naming guidelines.\u00a0<\/p>\n
The display of the relationships are important in these data models. The three most common types are unary, binary and ternary. Unary is a recursive relationship. Binary is between instances of two entity types (most common). Ternary a relationship among three entity types. Diagrams can show mandatory or optional relationships and even subtypes and supertypes (hierarchy).\u00a0<\/p>\n
Industry-specific data models are common and packaged data models can reduce cost for an organization.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
The previous chapter focused on the flow of information and processes, while Chapter 8 of MSAD focused on data requirements. Data models are important because they can serve as the foundation for database design. And since data are often the most complex aspects of information systems, data modeling needs to be comprehensive and accurate. One […]<\/p>\n","protected":false},"author":25071,"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":["post-573","post","type-post","status-publish","format-standard","category-instructor","entry"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/community.mis.temple.edu\/mis5203sec001spring2021\/wp-json\/wp\/v2\/posts\/573","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/community.mis.temple.edu\/mis5203sec001spring2021\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/community.mis.temple.edu\/mis5203sec001spring2021\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/community.mis.temple.edu\/mis5203sec001spring2021\/wp-json\/wp\/v2\/users\/25071"}],"replies":[{"embeddable":true,"href":"https:\/\/community.mis.temple.edu\/mis5203sec001spring2021\/wp-json\/wp\/v2\/comments?post=573"}],"version-history":[{"count":1,"href":"https:\/\/community.mis.temple.edu\/mis5203sec001spring2021\/wp-json\/wp\/v2\/posts\/573\/revisions"}],"predecessor-version":[{"id":574,"href":"https:\/\/community.mis.temple.edu\/mis5203sec001spring2021\/wp-json\/wp\/v2\/posts\/573\/revisions\/574"}],"wp:attachment":[{"href":"https:\/\/community.mis.temple.edu\/mis5203sec001spring2021\/wp-json\/wp\/v2\/media?parent=573"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/community.mis.temple.edu\/mis5203sec001spring2021\/wp-json\/wp\/v2\/categories?post=573"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/community.mis.temple.edu\/mis5203sec001spring2021\/wp-json\/wp\/v2\/tags?post=573"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}