business analysis glossary

This content is an extract from GetAhead in Business Analysis - the FULL course is in eBook and multimedia CD-Rom format.

Attribute.
Each entity typically has a 'data group' associated with it.
The elements of this data group are referred to as the 'attributes' or 'data items' of the entity.
The distinction between what is an attribute of an entity and what is an entity in its own right may not be clear without careful consideration.

Bottom Level.
Elementary or bottom level processes represent modest and discrete functions that do not require further analysis.
Elementary processes can occur at any level of diagram - including level 1.
At this level, the process should have a brief and specific title and between 2 and 8 data flows surrounding it.
Elementary Process Descriptions (EPD's) can be used to describe the purpose of the process and are typically about half a page of narrative.

Boundary.
The boundaries of the investigation are set to define the scope of the study.
The context diagram is useful in agreeing the overall system boundary.
At lower levels of investigation a boundary is defined by the process that is being decomposed (or leveled) during the top down expansion.

Business Process Diagram.
A business process model comprises one or more business process diagrams, each being a pictorial representation of a specific area of the business.
Any process on a business process diagram that merits closer scrutiny is further analyzed and may give rise to an 'offspring' business process diagram.
It is in this way that the business process diagram hierarchy evolves - into a business process model (BPM) for the given investigation.

Business Process Model.
A business process model comprises one or more business process diagrams, each being a pictorial representation of a specific area of the business.
Any process on a business process diagram that merits closer scrutiny is further analyzed and may give rise to an 'offspring' business process diagram.
It is in this way that the business process diagram hierarchy evolves - into a business process model (BPM) for the given investigation.

Candidate Key.
Each occurrence of an entity type can be uniquely identified by its primary key.
Where several possible primary keys exist they are termed candidate keys.

Cardinality.
The extent to which an entity may relate to another is termed the degree or maximum cardinality. These maximum cardinalities may be combined to give three possible degrees of relationship;
i) One-to-One
ii) One-to Many
iii) Many-to-Many
If an entity has a crows-foot drawn against it, then many occurrences of that entity may relate to the other entity. Conversely if no crows-foot is drawn against it, at most one occurrence of that entity may relate to the other entity.

Compound Key.
Each occurrence of an entity type can be uniquely identified by its primary key.
If two or more data items are used as the unique identifier, then this represents a compound key.

Connection Trap.
It may be wrongly assumed that because entities appear to be connected on the data model then association between individual entity occurrences is possible.
However the existence of a relationship between two entity types does not automatically imply that specific occurrences can be linked.
The problem of specific occurrences failing to have a valid communication path, whilst there types are linked on the data model is called a 'connection trap' and is most commonly resolved by introducing a link entity.

Context Diagram.
This is a diagram that represents the entire system as if it were a single process. It is often used to agree the system boundary with the client and/or expert users.
The context diagram is sometimes referred to as the level 0 Diagram.

Data Flow.
A data flow represents a package of information flowing between objects.
It may be shown as a 2 way flow on high level diagrams only.
The data flow is shown by a line, with an arrow-head showing the direction of the flow.

Data Group.
Each entity typically has a 'Data Group' associated with it, it is the sum total of the elements of a data group that comprise the specific entity occurrence of a given entity type. The elements of this data group are referred to as the 'Attributes' or 'Data Items' of the entity. The distinction between what is an attribute of an entity and what is an entity in its own right is often unclear without careful consideration.

Data Item.
Each entity typically has a 'Data Group' associated with it.
The elements of this data group are referred to as the 'Attributes' or 'Data Items' of the entity.
It is the sum total of the data items (elements of a data group) that comprise the specific entity occurrence of a given entity type.

Data Store.
A Data Store is a holding place for information within the system.
Data stores may be long-term files such as sales ledgers or may be short-term accumulations. For example, daily batches of documents awaiting processing.
Data stores are represented by an open ended narrow rectangle.

Decomposition.
This is the process by which a given business process diagram is further analyzed.
Any process on a business process diagram that merits closer scrutiny is further analyzed and may give rise to an 'offspring' business process diagram.
It is in this way that the business process diagram hierarchy evolves - into a business process model (BPM) for the given investigation.

Degree.
The extent to which an entity may relate to another is termed the degree or maximum cardinality. These maximum cardinalities may be combined to give three possible degrees of relationship;
i) One-to-One
ii) One-to Many
iii) Many-to-Many
If an entity has a crows-foot drawn against it, then many occurrences of that entity may relate to the other entity. Conversely if no crows-foot is drawn against it, at most one occurrence of that entity may relate to the other entity.

Detail Entity.
In a 'one to many' relationship the entity at the 'one' end is normally referred to as the master and the entity at the 'many' end referred to as the detail entity.
This can more easily be remembered as 'little keys own big keys' - the big keys being the detail (many) end of the relationship line - i.e. the crows foot.
If entities in a one-to-one relationship have to be resolved into a one-to-many relationship the analyst must decide which entity is the 'master' and which is the 'detail'. If the relationship is time dependent and one entity exists before the other, then the one created first is deemed to be the master.

Document Flow Diagram.
This approach is appropriate if the part of the business under investigation consists principally of flows of information in the form of documents or computer input and output. Each source/recipient is represented as an oval and the documents are represented as flows between them.
The document flow diagram serves as the start point for the top level (level 1) business process diagram.
The activities relating to the sending or receiving of the major documents within the system boundary are now represented as processes - forming the basis of the level 1 diagram.

Elementary Process.
Elementary or bottom level processes represent modest and discrete functions that do not require further analysis.
Elementary processes can occur at any level of diagram - including level 1.
At this level, the process should have a brief and specific title and between 2 and 8 data flows surrounding it.
Elementary Process Descriptions (EPD's) can be used to describe the purpose of the process and are typically about half a page of narrative.

Entity.
An entity is something of significance to the system being studied. A clear cut definition of an entity is not really possible, they even vary in nature.
Each entity has a data group associated with it. The elements of this data group are referred to as the 'attributes' of the entity. Entities are always named in the singular.

Entity Cross Reference.
In this formal approach to entity identification each entity is marked along both the horizontal and vertical axis of a grid, so that each intersection in the grid represents a potential relationship. For each pair of entities the possibility of a 'direct' and 'relevant' relationship is considered.
'Direct' indicates that a link exists between them which does not rely on an intermediate entity. 'Relevant' indicates that the relationship is of interest to the system.

Entity Description.
All Entities should be described on a standard form, called an Entity Description.
These forms should be designed to store all the information that is considered significant about the entity.

Entity Key.
Each entity occurrence is uniquely identified by using one or more of its attributes - the resultant identifier is called a Primary Key.
Compound Key : If two or more attributes are used the primary key is also a Compound Key.
Candidate Key : Where several possible primary keys exist they are termed Candidate Keys.

Entity Life History.
This is a diagrammatical representation of how the systems data is changed over time by the events that act on the system entities.
For each entity the Sequence, Selection and Iteration of events affecting it are depicted.
An event is whatever triggers a process to update the system data. For most systems it would be impractical to model all these events in one diagram. Therefore the effects of the events upon each entity in the data model are modeled individually - giving rise to a series of Entity Life Histories (ELH's).

Entity Occurrence.
Entity types are shown on the data model. An entity type will have multiple entity occurrences associated with it - each being a real world manifestation of the entity type. e.g. : Entity Type Entity Occurrence
Order Order No. 108976
Vehicle Reg No. K669 HRW
All entity occurrences will possess each and every data item (attribute) of the entity type.

Entity Type.
Entity types are shown on the data model. An entity type will have multiple entity occurrences associated with it - each being a real world manifestation of the entity type.
e.g. : Entity Type Entity Occurrence
Order Order No. 108976
Vehicle Reg No. K669 HRW
All entity occurrences will possess each and every data item (attribute) of the entity type.

Exclusive Relationship.
An Exclusive Relationship is one in which participation precludes participation in other relationships. Such relationships are said to be part of an exclusive relationship group (all relationships in an exclusive group must have the same subject entity and same optionality).
Two types of relationship group exist; a mandatory exclusive relationship, in which one of the relationships must apply, and an optional exclusive relationship in which none of the relationships need apply. In both cases, participation in any relationship of the group precludes participation in any other.

External Entity.
Entities are things of interest to the system that is being studied.
External entities are those which lie outside of the scope (control) of the system.
Entities can be transient in nature - such as a loan, or may even represent a target, such as booking a meeting hall.
In practice if it is something that the system needs to keep information about, it is likely to be an entity.

Foreign Key.
Each entity occurrence is uniquely identified by using one or more of its attributes -the resultant identifier is called a Primary Key.
A Foreign Key arises where an attribute of one entity is a Candidate Key for another entity.
Where several possible primary keys exist for an entity they are termed Candidate Keys.

Function.
A function is synonymous with a process and represents a transformation of data flows.
It can vary from the all encompassing function shown on a context diagram, to the elementary processes (or bottom level processes) which represent modest and discrete functions that do not require further analysis.

Hierarchic Relationship.
A recursive relationship is one in which an entity has a relationship with itself.
A hierarchic relationship is one in which the entity has a one-to-many relationship with itself.

Informal Identification.
This approach to the identification of entities lacks the thoroughness of the entity cross-reference grid.
However it will generally be quicker and the associated direct drawing of the data model allows indirect relationships to be seen more easily.
In this approach the drawing of preliminary diagrams and the identification of the entities is highly iterative.

Key.
Each entity occurrence is uniquely identified by using one or more of its attributes - the resultant identifier is called a Primary Key.
Compound Key: If two or more attributes are used the primary key is also a Compound Key.
Candidate Key: Where several possible primary keys exist they are termed Candidate Keys.

Level 1 Diagram.
Each Business Process Diagram exists at a level in the Business Process Model (BPM) hierarchy.
The context diagram is usually considered to be the level 0 diagram, this is followed by a diagram showing all the major processes of a system - this is the level 1 diagram. Decomposition of this gives rise to an indeterminate number of lower level diagrams. Many diagrams may exist at any level below level 1 but only one context diagram and one level 1 diagram are drawn.

Level 2 Diagram.
Each Business Process Diagram exists at a level in the Business Process Model (BPM) hierarchy.
The context diagram is usually considered to be the level 0 diagram, this is followed by a diagram showing all the major processes of a system - this is the level 1 diagram. Decomposition of this gives rise to an indeterminate number of lower level diagrams. Many diagrams may exist at any level below level 1 but only one context diagram and one level 1 diagram are drawn.

Link Entity.
Resolution of m:m relationships is carried out by introducing a link entity.
The link entity holds the data associated with the relationship between the original entities and both of these are deemed to be masters of the new entity.
It may be that the link entity will be a previously identified entity - in which case naming it will be easy. If not it should be given a unique and meaningful name.

Link Phrase.
The Link Phrase describes the relationship in a standard style. The link phrase is always read clockwise with respect to the entities.
The Link Phrase is one of the three key components of the relationship statement, the other components are :
Degree or Maximum Cardinality & Participation or Optionality.

Master Entity.
In a 'one to many' relationship the entity at the 'one' end is normally referred to as the master and the entity at the 'many' end referred to as the detail entity.
This can more easily be remembered as 'little keys own big keys' - the big keys being the detail (many) end of the relationship line - i.e. the crows foot.
If entities in a one-to-one relationship have to be resolved into a one-to-many relationship the analyst must decide which entity is the 'master' and which is the 'detail'. If the relationship is time dependent and one entity exists before the other, then the one created first is deemed to be the master.

Maximum Cardinality.
The extent to which an entity may relate to another is termed the degree or maximum cardinality. These maximum cardinalities may be combined to give three possible degrees of relationship;
i) One-to-One
ii) One-to Many
iii) Many-to-Many
If an entity has a crows-foot drawn against it, then many occurrences of that entity may relate to the other entity. Conversely if no crows-foot is drawn against it, at most one occurrence of that entity may relate to the other entity.

Network Relationship.
A recursive relationship is one in which an entity has a relationship with itself.
A network relationship is one in which the entity has a m:m relationship with itself.

Optionality.
A relationship can be fully mandatory, fully optional or 'contingent'.
A solid line is used to show that an entity occurrence must be associated with each occurrence of the other entity (mandatory).
A dotted line shows that an entity occurrence may be associated with each occurrence of the other entity (optional)
A line which is half solid and half dotted is used to that the relationship between
the entities is mandatory at one end and optional at the other (contingent).

Participation.
A relationship can be fully mandatory, fully optional or 'contingent'.
A solid line is used to show that an entity occurrence must be associated with each occurrence of the other entity (mandatory).
A dotted line shows that an entity occurrence may be associated with each occurrence of the other entity (optional)
A line which is half solid and half dotted is used to that the relationship between
the entities is mandatory at one end and optional at the other (contingent).

Physical Flow.
A physical flow or resource flow shows the flow of physical material from its source to its destination.
Resource flows are usually restricted to early, high-level diagrams and are used when a description of the physical flow of materials is deemed necessary.

Potential Entity.
In the early stages of developing the data model a list of potential entities may be drawn up. This list is then refined - following more detailed investigation of each candidate. Those considered to be actual system entities are then deemed to be entities, the others are rejected.

Preliminary Diagram.
Working from an initial list of entities a preliminary diagram is drawn, the aim of this diagram is to show an overview of the entities and their relationship lines.
This diagram is then adjusted as the entity list is refined.
Once this sketch is thought to approximately reflect the system it is refined through a series of preliminary diagrams until the final data model emerges.

Primary Key.
Each entity occurrence is uniquely identified by using one or more of its attributes -the resultant identifier is called a Primary Key.
Compound Key: If two or more attributes are used the primary key is also a Compound Key.

Process.
A process represents a transformation of data flows.
Typically this is a function carried out by the system being studied.
It can vary from the all encompassing process shown on a context diagram, to the elementary processes (or bottom level processes) which represent modest and discrete functions that do not require further analysis.

Recursive Relationship.
A Recursive Relationship is one in which an entity has a relationship with itself.
A recursive relationship may be one of two types;
1) A hierarchic relationship is one in which the entity has a one-to-many relationship with itself.
2) A network relationship is one in which the entity has a many-to-many relationship with itself.

Redundant Relationship.
Redundant relationships should be removed from the data model.
The data model diagram should be checked to ensure that all the relationships drawn are necessary; that information would be lost if they were removed.
Areas of the diagram where relationships form loops should be given special consideration, as they may indicate the existence of redundant relationships.
N.B. It is very important to think very carefully before removing apparently redundant relationships, or important information flows may be lost.

Relationship.
A relationship is defined as an association between two entities to which all occurrences of the entities must conform. It is represented diagrammatically by a line that joins the two relevant entities.
The relationship line shows two reciprocal relationships; that of the first entity with respect to the second and that of the second entity with respect to the first.
Each relationship line shows three distinct properties of the relationship;
- Relationship link phrase.
- Participation or Optionality.
- Degree or Maximum Cardinality.

Resource Flow.
A physical flow or resource flow shows the flow of physical material from its source to its destination.
Resource flows are usually restricted to early, high-level diagrams and are used when a description of the physical flow of materials is deemed necessary.

Subtype.
Where a system has a recognizable sub-set of occurrences of the same entity type, the sub-set(s) are known as entity subtypes, the original entity type being the super-type. Subtypes are usefully defined where an identifiable group of an entity occurrences have additional attributes to those of the super-type. They can also be useful if a subtype can be seen to be involved in additional business roles.

Super-type.
Where a system has a recognizable sub-set of occurrences of the same entity type, the sub-set(s) are known as entity subtypes, the original entity type being the super-type. Subtypes are usefully defined where an identifiable group of an entity occurrences have additional attributes to those of the super-type. They can also be useful if a subtype can be seen to be involved in additional business roles.
All attributes and relationships of the super-type must belong to all its subtypes.

System Boundary.
The boundaries of the investigation are set to define the scope of the study.
The context diagram is useful in agreeing the overall system boundary.
At lower levels of investigation a boundary is defined by the process that is being decomposed (or leveled) during the top down expansion.

This content is an extract from GetAhead in Business Analysis - the FULL course is in eBook and multimedia CD-Rom format. TOP