[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-655952-105":59,"doc-detail-655952-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","e-r-design-decisions-decision-guidance-for-er-modeling","E R design decisions - Decision guidance for ER modeling","","Content explains how to model desired reality in an entity-relationship (E R) framework using iterative design and careful choice of entities, attributes, and relationships. It covers common modeling decisions such as entity vs attribute, concept as entity vs relationship, selecting ternary versus binary relationships, and when to apply specialization/generalization, aggregation, and modularity. It then details translating entity and relationship sets into relational schemas, including strong/weak entities, N:N, 1:N, and 1:1 mapping rules and handling multivalued attributes.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":30,"@type":76,"position":81},"https://docshare.wps.com/document/technology/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/e-r-design-decisions-decision-guidance-for-er-modeling/655952/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/e-r-design-decisions-decision-guidance-for-er-modeling/655952.png","ImageObject",300,407,{"name":92,"@type":93},"Eliana","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-31","2026-10-25",true,{"@type":102,"interactionType":103,"userInteractionCount":24},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"Why is designing an ER model considered an iterative process?","Question",{"text":112,"@type":113},"It starts with an initial design and is gradually refined, because multiple choices may exist and not every choice is strictly right or wrong.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How do you decide whether something should be an entity, an attribute, or a relationship?",{"text":117,"@type":113},"The decision depends on how the concept functions in the organization being modeled; crucial aspects should be modeled with a more prominent role, such as an entity rather than just an attribute.",{"name":119,"@type":110,"acceptedAnswer":120},"How are N:N relationships represented when translating an ER diagram to relational schemas?",{"text":121,"@type":113},"They require their own schema (table) containing the primary keys of the participating entity sets and any additional attributes describing the relationship.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},655952,1792965074,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":29,"category_name":30,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":24,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":19,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":129,"read_time":52},4398048949847,"https://ap-avatar.wpscdn.com/avatar/400002536579ef2da7f?_k=1778318612642679267","• It is not always easy to decide on the best way to model the reality one wishes to describe.  \n◦ The design process is an iterative process  \n◦ You start with an initial design and gradually refine that  \n• Sometimes it is hard to decide whether something should be represented as an entity, an attribute or a relationship.  \n◦ There are often several ways to model the reality you want to describe  \n◦ You cannot always say that one way is right or wrong; some of these decisions are simply design matters  \n• How you design your model is very much dependent on the company or the organization that you model, and the role of the things modeled have in the functioning of the organization.  \n◦ Things crucial to the organization should get a more eminent role in the model (eg rather an entity than merely an attribute)  \nE R design decisions  \n• Should I use an attribute or an entity to represent an object?  \n• Should a concept from the real world be represented as an entity or as a relationship?  \n• Should I use a ternary (3 ) or a set of binary relationships?  \n• Should I use a strong or a weak entity?  \n• When is it worth the while to use specialization and generalization?  \n◦ These promote the modularity of your design  \n• When should I use aggregation?  \n◦ You can use the aggregated entity set as one single unit without having to pay attention to its internal structure.  \n• You can translate the entity sets and relationship sets of an E R diagram in a consistent way into relational scemas that represent the contents of the database:  \n◦ A database that is modeled by an E R diagram can be represented as a set of schemas.  \n• For each entity set and each relationship set you generate a unique schema  \n◦ Name the schema after the corresponding entity or relationship set in the E R diagram!  \n• Each schema has a number of columns with names that are unique in this schema.  \n◦ These usually correspond to the attributes in the E R diagram.  \nHow to represent entity sets as schemas:  \n• A strong entity set is translated into a schema (a table) with the same attributes (columns) as it has in the E R diagram.  \n• A weak entity set is translated into a schema with the same attributes, plus a column for the primary key of the corresponding strong entity set that the weak set is dependent upon.  \n◦ No separate table is created for the relationship between the weak entity and its identifying strong entity set!  \nHow to represent relationship sets as schemas:  \n• N:N relationships must get their own schema with the following attributes (columns):  \n◦ The primary keys from the two entity sets that partake in this relationship  \n◦ Other attributes that describe this relationship in the E R model  \n• 1:N relationships can be reduced so that they are merely represented by a referencing attribute in the table for the N entity:  \n◦ Both the connected entities get their own schemas  \n◦ In the schema for the N entity you include the primary key for the 1 entity (it will function as a foreign key to reference the 1 entity) . E g if you have the entity project and the entity customer , with a relationship orders between, and every project can have only one customer who ordered the project, you can put the primary key (e g customer nr) of the entity customer into the schema (table) for project. Any other attributes describing this relationship would in that case be put in the table project as well.  \n• An alternative for reducing an 1:N relationship is to represent it as a table of its own, including  \n◦ The primary keys from the two entity sets that partake in this relationship  \n◦ Other attributes that describe this relationship in the E R model  \n◦ This is a better solution if the participation in the relationship is low by the N side (i e we have a number of entities on the N side that are not connected to any entity on the 1 side); otherwise we shall get a lot of NULL values in the N side table.  \n• 1:1 relationships are often reduced: you place the","cbCairtTKZ50PAbo","https://ap.wps.com/l/cbCairtTKZ50PAbo","pdf",318224,"English","# ER design decisions\n## Modeling choices: entities, attributes, relationships\n## Designing organization-dependent models\n## Translating ER diagrams into relational schemas\n## Entity sets as schemas\n## Relationship sets as schemas\n## Mapping N:N, 1:N, 1:1, ternary relationships\n## Handling multivalued attributes","[{\"question\":\"Why is designing an ER model considered an iterative process?\",\"answer\":\"It starts with an initial design and is gradually refined, because multiple choices may exist and not every choice is strictly right or wrong.\"},{\"question\":\"How do you decide whether something should be an entity, an attribute, or a relationship?\",\"answer\":\"The decision depends on how the concept functions in the organization being modeled; crucial aspects should be modeled with a more prominent role, such as an entity rather than just an attribute.\"},{\"question\":\"How are N:N relationships represented when translating an ER diagram to relational schemas?\",\"answer\":\"They require their own schema (table) containing the primary keys of the participating entity sets and any additional attributes describing the relationship.\"}]","E R design decisions - Decision guidance for ER modeling | PDF"]