Lecture 1B - EA as a set of models Flashcards
What is Enterprise Architecture (In a very simple definition) ?
A combination of tens of thousands artifacts (lists, tables, diagrams) that describe a business and its systems.
-Includes: Current state, future state and migration plan
What is Information Technology (IT)?
The combination of:
- Hardware
- Software
- Data
- Network
- Procedures
- People
What is a flowchart?
A diagram that represents a workflow or process. *It can also be a representation of an algorithm.
What are the most common notations in a flow chart?
- Arrow is the flowline
- Oval rectangle is a start or end point
- A block is a process
- A triangle is a decision
- An italic rectangle is an input or output
What 3 types of views do you have in a flowchart?
- Designer view (with the notations described)
- Developer view (In programming language)
- In user view (in CMD exe)
What are data models and which 2 views do you have?
-> Models about databases
User view - Expressed in a spreadsheet style
Developer view - SQL language
What is a Physical Database model?
A database model for database engineers that is dependent on the technology they use.
- It shows columns in separate table, with in the table a candidate key, a primary key and a foreign key.
- Related columns are linked by lines.
What is the Logical Database model
A database model for database designers/architects. It is technology independent and often uses the Relational Model.
- It shows which tables are present in the database.
- It shows the attributes of each tables in a row, with the primary key underlined.
- The primary keys are linked to the foreign keys in other tables with arrows.
What is the Conceptual Data(base) model?
A database model for business owners / analysts. It is Design and Technology independent and often uses the Entity-Relationship model.
- It shows Entities as separate tables with their attributes. Attributes are listed in the tables Identifiers (PK) are underlined;
- It shows relationships between the tables as well as their cardinality;
- Composite attributes have round brackets;
- Multi-values attributes have curly brackets;
- Calculated attributes have square brackets;
Which user uses the Conceptual Database model?
Business Managers / Analysts
- Entity Relationship Model
Which user uses the Logical Database model?
Database Designers / Architects
- Relational Model
Which user uses the Physical Database Model?
Database Engineers
- Technology Dependent
What are the main differences between a Conceptual Model and a Logical Model?
- Logical (Designers) only has 1-N and 1-1 relationships whereas Conceptual Model (business) has N-N relationships;
- Conceptual model may lack identifiers, because business managers might not be aware of them. Logical model needs to have PK’s.
What is the process of developing a database system?
Step 1: Make conceptual model for current state
Step 2: Make conceptual model for to be state
Step 3: Map the conceptual model into the logical model
What is UML?
Unified Modeling Language. - Several software engineering diagrams under 1 umbrella.
Focus:
- Use-case diagram
- Activity diagram
- These are used in system diagrams and business diagrams
What is a system use-case diagram?
- Diagram about what a system does.
- Providing a bird view
- Design-dependent & Technology-independent
- Shows which functionalities (use cases) are supported in a system (Registering/login/watch movie/log out)
- Shows the relationship between functionalities
When is a functionality considered a functionality?
When it has at least two steps
What are the most important symbols in a system use-case diagram?
- The actor is portayed with a circle with a smiley or with a poppetje
- Use cases are circles
- The system is a big non-filled square around the functionalities
- Relationships are arrows
What is a system activity diagram?
- A diagram about a system that shows how the system does that. It focuses on a specific functionality that is given in a system use-case diagram;
- Shows all the steps that are taken with the system to successfully complete the functionality/process;
- Often a swimlane model. The lanes are the different actors involved in the process;
- Design dependent and technoloy-independent;
What are the most important symbols in a system activity diagram?
- A square with round edges is an action;
- An arrow indicates the action flow;
- A triangle is a decision point;
What is a business use-case diagram?
- A diagram about what the business does.
- Design independent
- Gives a bird view
- Shows the functionality of a business
- Shows physical, manual and digital functionalities;
- Involves external actors, such as customers, suppliers
What is a business activity diagram?
- A diagram about how the business does it;
- Gives a detailed view of all the steps for a single business functionality
- Often a swimlane model, in which the lanes are actors (can include outside actors like customer and delivery guy)
- Same symbols as for the system activity;
How do the business and system use case and activity models relate to each other?
- Business diagrams are conceptual whereas the system diagrams are logical
- The activity diagrams of each give a detailed view of a functionality within a use-case diagram;
- The bussiness activity diagram helps developing the system activity diagram
- The business use case diagram helps developing the system use case diagram
What is the CRUD Matrix?
A matrix that helps connecting diagrams to see if the combination of them is valid.
C -> Create
R -> Read
U -> Update
D -> Delete
- You can put entities in the columns and functionalities as rows;
- Can be used to check the current state and to see per entity column if there are functionalities or processes missing
What do all entities need to have in the CRUD Matrix?
C, R, U and D
Otherwise there is a functionality missing.
What do all functionalities need to have in the CRUD Matrix?
At least a C, a U or a D
Otherwise the functionality is incomplete
What is the Operational Node Connectivity (OV-2) diagram?
A diagram that can be put in the Where column and the business management perspective in Zachman.
Shows Operational nodes (locations of the organization) and arrows in between them listing the exchanging resources
What is the system resource flow description (SV-2)
A diagram that can be put in the Where column and the Architect perspective of Zachman.
Shows the application or network nodes and arrows between them to show the information flows.
What are three rules in the Zachman Framework?
- Flexibility (you can choose if you want to use use-case or activity models for each cell)
- Consistency. Cells in columns and rows should be associated. (Use CRUD)
- Consistency in columns shows IT-Business alignment
What are some final remarks on Zachman from Smits?
- It is not a practical framework (does not say what types of artifacts you should use)
- Does not suggest a methodology on how to make models or which models to make
In which rows can you find the business architecture in Zachman?
Comprised of the executive and business management rows
*All columns except ‘what’
In which rows can you find the system/application architecture in Zachman?
In the Architect row
- All columns except ‘what’
In which rows can you find the technology architecture in Zachman?
The Engineer row
- All columns except ‘what’
In which column can you find the data architecture in Zachman?
The what column
- All rows except the Technician row
