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