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They describe the data constraints that exist in the environment. is going to pay for it. Each instance of the generic entity and its associated instance of one of the category entities represents the same real-world thing and, therefore, have the same unique identifier. `  i) g g ? An identifying relationship means that the child entity's primary key inherits its parent entity type's primary key. A domain is a named type of data representation that may apply to one or more attributes. ? Abbreviations and acronyms are permitted; however, the entity name must be meaningful and consistent throughout the model. Because the ARTS Data Model is mature, its conceptual view is subsumed into a Fully Attributed Data Model.

A single line under the circle indicates an incomplete set of categories. 0 R Click to edit Master text styles Second level Third level Fourth level Fifth level ! 0 0 h ? A relationship identifies, names and defines an association between two entity types. 0 h ? The relationship name is always expressed in the parent-to-child direction, such that a sentence can be formed by combining the parent entity name, relationship name, cardinality expression, and child entity name. Naming Relationships The relationship appears as a line connecting two entities. p F 0 8 0 h ? IDEF1X models define data in a fully normalized structure, which allows an initial model to be extended without altering the initial set of entities, relationships, and attributes. An attribute value in the generic entity instance determines to which of the possible category entities it is related. Consider the terms item, article, product, SKU and merchandise. ? A path assertion might state that "employees may only be assigned to projects which belong to the same department for which they work". C BU C EN G HZ IE Q [ ? ` ) ? ( | " U 9 U 9 E `T 9 E `T "

An entity is "identifier-dependent" or simply "dependent" if the unique identification of an instance of the entity depends upon its relationship to another entity. ( The data model (particularly a third normal form relational model) reduces this risk by insisting on a consistent representation of each data element in a single place in the data model. This is illustrated in the next diagram. If an ordered item is not correctly aligned with the vendors catalog product code and the order is placed some party (the customer, retailer, vendor, etc.) example, if an employee can be assigned to many projects and a project can have many employees assigned, then the connection between the entities EMPLOYEE and PROJECT can be expressed as a non-specific relationship. p F q 0 a A relationship verb phrases may be established for both directions of a relation between two entities. ( # ( Additional support for data movement and transformation is also required. ( This same issue comes up when developing reports. A small circle indicates the relationship is optional for the connecting entity, meaning that an instance of the originating entity does not have to satisfy that relationship. T ) 1 ? The sample receipt shows how each subtype of RetailTransactionLineItem reflects different sales receipt line items. ile maintaining the "economy of concepts" associated with basic E-R modeling. 0 l

It establishes a common language for retailer organizations and individuals to communicate using explicitly defined words. A Logical Data Model data model is composed of: Each instance of these object types are uniquely identified and defined in business terms. A dashed line depicts a non-identifying relationship between the parent and child entities. @ %W"^.J '`:u*di_|tM^UUjv\[+9^C 4L3i,aK0@ @ @ @N[+WSnpcbbb*;zrcmX99E)I/cqf%. In the example, this implies that an employee cannot be both salaried and hourly. The default child cardinality is zero, one, or many. Data modeling provides a formal set of tools and procedures to make information useful. 4 0 h ? Within IDEF1X, the following relationship cardinalities can be expressed: If an instance of the child entity is identified by its association with the parent entity, then the relationship is referred to as an "identifying relationship". Most retail decision makers rely on information to make decisions because they can not personally visit and observe every retail site personally.

C BU C EN G HZ ID Q D ? @ 33 @ @ @ s f Assertions that affect multiple relationships may also be defined.

Class relationships are shown by the subtype entities being drawn inside the supertype entity, as illustrated by the diagram above.

The Generic Entity may be an Identifier-Independent Entity (as shown) or an Identifier-Dependent Entity depending upon other relationships. Attributes are the most atomic parts of a data model. Although the relationship itself is not named explicitly, the generic entity to category entity relationship can be read as "can be." An "inverse" relationship is defined that describes the relationship in the opposite direction. Entities introduced to resolve non-specific relationships are sometimes called "intersection" or "associative" entities. T d) 1 ? Each entity type has a unique, singular noun phrase assigned as its name. T  h) g g ? @ H `  j) g g ? The name of each relationship between the same two entities must be unique, but the relationship names need not be unique within the model. ps. T D  1 ? Relationship names are represented as verb phrases. ) A * Figure 97 - Entity Subtype Relationship Example. 0 2 That is, the specification of how many child entity instances may exist for each parent instance. The Sarbanes Oxley Act of 2002 mandates detailed reporting and tracking of business operational and financial controls. In an entity diagram an attribute name that is a foreign key is designated with a "(FK)" suffix. T  g g ? 0 h ? `  g g ? If the circle has a double underline, it indicates that the set of category entities is complete.

0 h ? In an entity diagram, entity types are represented as rectangles. G/* d 6 ? As modeled here, a RetailTransaction may have zero, one or many RetailTransactionLineItem entity instances associated with it. For example a Brand may apply to zero, one or many Item entity type instances. S 33 P ( Domain - set of values which the attribute can take on Format - characterization (ex, text, date, time, money.media) Length - number of characters or digits Default value - initial value when first instantiated Derivation algorithm - for derived attributes, the algorithm that is used to derive the attribute ` ` ? A relationship is a type of attribute pointing to an entity instead of a data type. > , l Logical models, in addition to identifying entities, attributes, relationships and domains define what each instance of these object means. The name of the generic entity attribute used as the discriminator is written beside the circle. Describing attributes _ Attribute name Alias(s) Definition Existence constraints - what other data is this attribute dependent on Business rules - business policy that defines one or more assertions that represent constraints. This means that the child entity references its parent entity type but is not dependent on the parents existence for its own existence. 0 h ? It will have a Description attribute, etc. Cardinality expresses the count of child entity type instances that may exist for a parent entity type. In a relational data model, an attribute cannot exist independently from an entity type. If the complete set of categories is referenced, the relationship may be read as "must be." 0 C ) `0 H q 0a 2 $ Because relationships are two-way, a phrase is defined for both ends of the relationship. IDEF1X provides a full set of semantic modeling capabilities wh l Depending on the size and complexity of the organization, these systems are part of a set of applications whose data must be turned into information, then distilled into knowledge on reports for senior executives. 0

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C BU C EN G HZ ID Q D ? ___ f 3 f . A specific connection relationship is depicted as a line drawn between the parent entity and the child entity with a dot at the child end of the line. ) A * H (Also see Foreign Keys Semantics [. C k) ) l From a relational database point of view this means that the inherited attribute may be null -- that is point to nothing. (Also, see Foreign Keys Semantics). The noun phrase is singular, not plural. A t t r i b u t e s a r e t h e f i e l d s t h a t d e s c r i b e a n e n t i t y . A relationship is given a name, expressed as a verb phrase (a verb with optional adverbs and prepositions) placed beside the relationship line. d d @ @@ `` ^ V X S j) 0 ` ) H The IdentityGTIN is based on a VARCHAR(14) base data type which is used by most SQL standard databases. Category entities are also always identifier-dependent. U 8 U 8 D `T 8 D `T 9 Y 2 Although an entity may be drawn in any number of diagrams, it only appears once within a given diagram. 4 C D) 0 H Z  T g g ? l Domains enable retail-specific data types to be derived from SQL base data types.

Moving the mouse pointer over the entity box will cause its definition and a list of related ER diagram names displayed in two separate frames. $ l P 5 order 2 r For example, an "exclusive OR" constraint states that for a given parent entity instance if one type of child entity instance exists, then a second type of child entity instance will not exist. A non-specific relationship is named in both directions. The connection relationship may be further defined by specifying the cardinality of the relationship. This is because the broad retail framework is well established and it is in a stage of development where it is being extended and enhanced not created from scratch. The rules governing the way point of sale discounts are treated by a retailer are likewise reflected in the way price modification rules are related to retail transaction sale return items and promotions. d d @ " @ ` " n ? " Where some are used as synonyms, they are explicitly referenced as such. The parent entity in an identifying relationship will be identifier-independent unless the parent entity is also the child entity in some other identifying relationship, in which case both the parent and child entity would be identifier-dependent. Figure 96 - Sample Entity, Attribute and Simple Relationship.

The complex web of relationships that define retailer business rules is explicitly presented through entity relationship models. Data accuracy has a direct, unambiguous impact on the bottom line.

Entities appear as round-cornered boxes on the diagrams. Each parent entity instance is associated with some exact number of child entity instances. They cannot be decomposed into lower level components. l The business and technical meta data for these systems data constitute an information architecture that can both guide the development of internal controls and give corporate principals the confidence that the reports they sign are valid. C ) 0 ) H The diagram below illustrates the assignment of a definition to the ItemID attribute of Item. The data model concepts discussed here provide the kind of support required to support regulatory reporting compliance. The U.S. Air Force IISS and IDS projects have successfully demonstrated the use of IDEF1X mo

$ C d) ) l A categorization relationship is shown as a line extending from the generic entity to a circle which is underlined. In some companies middle and senior managers spend an inordinate amount of time manually reconciling inconsistently defined data. Business rules The policies by which an enterprise runs the business often designate constraints on the data used within the enterprise can be fount while developing the E-R data model: in entities relationships attributes domains ( - - Data Normalization V Normalization is a formal technique to develop a highly structured data model By using three basic normalization steps we: elimination of data redundancy structuring of the data for ease of maintenance and modification, done by reducing the anomalies involved with creation, updating and deletion of data end up with a more stable data model ( { { First Normal Form All attributes of an entity must have exactly one single occurrence in each instance a schema whose attributes are all single valued First Normal form (cont) 2 The relationship is written as a verb/verb phrase along the line use present tense for the verb/verb phrase 2 Describing relationships Relationships convey a lot of information as it is derived from the current business practices and ploicies of the organization Characteristics: Relationship name Description : unambiguous description of the role and purpose of the relationship Cardinality : describe how many instances of the parent entity are connected to how many instances of the child entity (on-to-one, one-to-many, many-to-many) Existence constraints: does the relationship depend on other relationships Business rules : business policy that defines one or more assertions that represent constraints. IDEF1X has proven to be a useful and powerful tool for modeling a conceptual schema. C ) ) l 0 C ) l $ 0 h ? Accordingly all attributes are always identified and shown as part of entity types. G/* d 6 ? 4 l The data model by defining each entity type clarifies what each term means. A primary key is one or more attributes that have values used to uniquely identify and distinguish each entity type instance from each other. See Figure 4-6. Data models reflect important retail business assumptions and constraints. See Figure 4-5. In a non-identifying relationship, the parent entity primary key is inherited by the child entity as a non-primary key attribute. They each mean different things to different people. From the previous example, EMPLOYEE is the gen

A * H ( n relationship.". are related in a data model. An IDEF1X model of a conceptual schema can be easily subsetted and formally mapped through relational algebra to both external and internal schema. ` ) T Click to edit Master title style ! 8 C d) l A "complete categorization relationship" is a relationship between two or more entities, in which each instance of one entity, referred to as the generic entity, is associated with exactly one instance of one and only one of the other entities, referred to as category entities. If the parent entity type is deleted in this scenario, this scenario, the child is deleted. It also illustrates how foreign keys and cardinality are presented in an entity diagram. ___ f 3 f , ( C BU C EN G HZ IE Q [ ? d d @ , | ? " Category Entities will always be Identifier-Dependent Entities. y\)GEEJPNG ( Payment Card Industry (PCI) compliance which imposes procedures retailers must implement to protect credit card accounts of their customers requires retailers to map and understand the kinds of data they collect. T Click to edit Master title style ! Another type of constraint is a "path assertion," which constrains the specific instances of parent and child entities when two entities can be related either directly or indirectly through two different sequences of relationships. One type of assertion may specify a Boolean constraint between two or more relationships. The result of applying the IDEF1X modeling technique is a specification of data meanings and rules typically represented by the following: In key-based and fully attributed models, a distinction is made between two types of entities. ips would specify that an employee has zero, one, or more project assignments and that a project has zero, one or more project assignments. C a r d i n a l i t y - d e s c r i b e s t h e n u m b e r o f e n t i t y r e l a t i o n s h i p s t h a t c a n e x i s t a t e a c h e n d o f a r e l a t i o n s h i p ( o n e - t o - o n e , o n e - t o - m a n y , m a n y - t o - m a n y ) E n t i t y S u p e r t y p e / s u b t y p e - a n e n t i t y c a n b e d i v i d e d i n t o t w o o r m o r e s u b t y p e e n t i t i e s , e a c h s u b t y o e c a n h a v e a t t r i b u t e s o f i t s o w n .

Data models are a prerequisite to operating a retail enterprise in today's business climate. 4 C ) l

Rules are no longer shown on the diagrams. Each parent entity instance must have at least one or more associated child entity instances. As discussed under entity type, a primary key is composed of one or more attributes and serves as a unique entity type instance identifier. *_N nxK? That means that the child entity type's existence is dependent on its parent entity type's existence. Semantics is the branch of linguistics and logic concerned with meaning. T 1 ? The Child Entity in a non-identifying relationship will be an Identifier-Independent Entity unless the entity is also a Child Entity in some Identifying Relationship. ) g g 1 ?

If the entity is identifier-dependent then the corners of the box are rounded. Associated with each line are verb phrases which define the relationship between the two entities. In a relational data model there are two ways a parent and child entity type may be related. This is called a controlled vocabulary and it is a key value-adding feature of data modeling. ( The IDEF1X syntax does allow, however, for an incomplete set of categories. The operational and decision support systems are based on data being collected and stored in data structures such as tables and files, and then transformed and moved to become knowledge in reports that are signed by corporate principals. Identifying Attributes _ Interviews with users joint facilitated sessions Examining various business or system documents ` ` Naming attributes Each attribute of an entity should be uniquely identified names should always be singular a good practice is to always precede the attribute name with the entity name A glossary that defines the entities and attributes used in the diagrams. Data movement-related regulatory information is partially satisfied in the ARTS ODM V7.0/7.1 to ARTS DWM V3.0 extract, transform and load mapping. ( T 1 ? U , U , 8 `T , 8 `T 0 2

If the cardinality is an exact number, a positive integer number is placed beside the dot. U 9 U 9 E `T 9 E `T d n " The new relationsh A retail transaction line item provides a set of attributes (including line item number) that all subtypes share (i.e., inheritable by subtype children). These definitions provide the semantic content of a data model are are essential to the business relevancy of a relational model. ___ f 3 f {,C! The formality and discipline introduced by data modeling is vital in figuring out what retail reports actually are telling decision makers. May dictate the business conditions under which a relationship is created, modified ot deleted. A non-specific relationship is depicted as a line drawn between the two associated entities with a dot at each end of the line. p o t j }&.l&9z0MLlIy TT;VMF5mQBBP}b F[D7v>>U*us2vF0sGq {Q'9$/Zz89dh!gtMWvJ?)m+m#[t,I!e qq?hB|zyP!&\vYeW2vB@I+0^[T`9YSUgQ?+w`xk Y{>" * U3E7O%+jk^EZ:Q%NTKdcm;6;z?9zt{JJUT31O555$xw{*p9jKr @ @ @ @ @ @ ys[~TiR$`5!~yu1v8$5;jj;V7m'j}[XtJ:ge;yw4mg1cLj(.Js[355Zr(., 4#i6i#yuD{,?v)t)=,HCQ/+Jq;?0 @(HK/M|`r{u9GkX:j.4#,v6&Jq/I{>l(b;vGyv[A6B>rI'?fY=2qF2O B:tLG,Q\X|77l}?F+liJy5qnN=K_.^p?VppdzCw9%M^e]3um&*T'ZgTA @ E~vj$e. ` ? U , U , 8 `T , 8 `T q 0 a 2 ? 0 h ? However, if both the parent and child entities refer to the same real world thing, then a potential categorization relationship exists (See Categorization R The Sample Entity, Attribute and Simple Relationship diagram shows a NON-IDENTIFYING relationship between Item and Brand. Costs of Misinterpretation and Inconsistent Semantics, Data Model as a Reflection of Business Assumptions, Constraints and Rules, Data Modeling & Regulatory Reporting and Accountability. Data models are not just for information technologists. For example, the entity DEPARTMENT may have two child entities, EMPLOYEE and PROJECT. The entity name is a noun phrase (a noun with optional adjectives and prepositions) that describe the set of things the entity represents. To be useful, information has to be identified, named, described and organized into a coherent structure so it can be understood by decision makers. For example, Flag domains are limited to two values "YES" or "NO. C BU C EN G HZ I8 Q f3 ? The ARTS Operational Data Model, in technical terms, is a relational data model built using entity relationship modeling notation. ( C $)

An attribute identifies, names and defines a characteristic or property of an entity type. nQ

C Tl) ` ) H There are a variety of ways cardinality is used to express the relative counts of parent entity types to children entity types and they are presented in the Data Model Methodology and Notation Topic.

@ n ? " The absence of the small circle indicates a mandatory relationship, which must be satisfied for instances of the entity. 0 h ? See Figure 4-3. A "P" (for positive) is placed beside the dot to indicate a cardinality of one or more. ( Data models that establish an enterprise-wide controlled vocabulary eliminate one of the root causes of data inconsistency. ___ f 3 f ` ( For example, although an existence-dependency relationship may exist between the entities BUYER and PURCHASE-ORDER, purchase orders may be uniquely identified by a purchase order number without identifying the associated buyer. Data model diagrams are refined into three different levels of detail: Entity-relationship, the least detailed level. When viewing in a multi-frameset, moving the mouse pointer over to the small red box will cause the verb phrase shown on the status line, and the full description of the relationship displayed in the definition frame. Category entities for a generic entity are always mutually exclusive. U 8 U 8 D `T 8 D `T 2

That is, the associated project must be known in order to uniquely identify one task from all other tasks. 8 C ) `0 H For example, an EMPLOYEE can be a SALARIED-EMPLOYEE. ! The definitions supply the semantic content for a data model. From the previous example, it is inferred that "a task is part of exactly one project.". This non-specific relationship can be replaced with specific relationships later on in the model development by introducing a third entity, such as PROJECT-ASSIGNMENT, which is a common child entity in specific connection relationships with the EMPLOYEE and PROJECT entities. E n t i t y I n s t a n c e - A n e n t i t y i n s t a n c e i s a s i n g l e o c c u r r e n c e o f a n e n t i t y S y n o n y m s - a l i a s o r o t h e r n a m e s f o r a n e n t i t y o r a t t r i b u t e U n i q u e i d e n t i f i e r - t h e c o m b i n a t i o n o f a t t r i b u t e s a n d r e l a t i o n s h i p s t h a t u n i q u e l y i d e n t i f y e a c h i n s t a n c e o f t h e e n t i t i e s , L Identifying Entities C a n b e d i s c o v e r e d b y e x a m i n i n g a v a r i e t y o f b u s i n e s s d o c u m e n t s s u c h a s r e p o r t s , b u s i n e s s p l a n s , b u s i n e s s p r o c e s s d e s c r i p t i o n s & C o m m o n b u s i n e s s e n t i t i e s : C u s t o m e r s E m p l o y e e s V e n d o r s / S u p p l i e r s / P a r t n e r s P a r t s P h y s i c a l a s s e t s P r o d u c t s / S e r v i c e s L o c a t i o n s / p l a c e s / s i t e s / p l a n t s F i n a n c i a l a s s e t s ( Identifying Entities (more) The preceding entities could be grouped into 5 generic categories: People - employees, vendors, suppliers Place - sites, offices, plants, customer locations Things - products, parts Logical concepts - conceptional objects, services Events - time sequence entities, recurring events Naming entities: Always use singular names each entity name must be unique the entity name must clearly convey what the entity represents, qualifiers can be used for clarity P C C Describing Entities Each entity can be described with a set of properties: Entity name Alias(s) Definition Existence constraints Business rules Volumetrics Attributes Example(s) .