System Design

Question 1

3 Keys to Develop and Accounting System

Answer 1

-These are requirements to make the system and the items to consider when making it.

1) People = Accounting and IT professionals
(System Analysts, Database Designers, Database Developers, Application Developers, Network Specialist)

2) Processes = Structures to develop systems like SDLC and SDM
3) Technology = What technology will be used (Ex. Software, Database, DBMS, Network, Protocols, Cybersecurity)

Question 2

System Development Life Cycle (SDLC)

Answer 2

System Development Life Cycle = Specifies WHAT steps to complete. Analyzing, designing, organizing and integrating the three keys into a successful system

PAD-BID
Plan = triggered by opportunities the current system does not exploit. Identify the problem, need or opportunity to be addressed. Use Project Management to plan, schedule, budget it.

Analysis = Problem Analysis (understand/classify the problem using p-i-e-c-e-s), Requirement Analysis (see what business user needs fixed), Current System Model Analysis (modification to our current business process, database and people models)

Design = Build models for business processes (BPMN) database (ERD) and people. Evaluate feasibility of system design proposal.

Buy/Build = If custom > build > coded > implement prototype. If commercial > buy > implement. User approval/Testing of prototype is also in this step.

Install = Final product on enterprise server, fill with real data. Legacy System > New System

Deploy = longest phase, operating and maintenance of system

Question 3

System Development Methodology (SDM)

Answer 3

System Development Methodology (SDM) = Specifies WHEN the steps are completed. order, timing and progression of SDLC phases. When? How often? Which step?

Waterfall Methodology = SDLC phases in order one after another

Prototyping Methodology = take initial user requirement and PAD-Build a prototype. Test and get feedback, then repeat until prototype is ready for BID.

ABC Methodology = Most accounting systems today are developed this way. Baseline (like waterfall) and Customization (like prototyping)

Question 4

Relational Database Management System (RDBMS)

Answer 4

RDBMS = Software used to create, manage, maintain and manipulate a relational database. It interacts with accounting software to insert, update and delete (DUI) from database.

-It enforces anomaly-free database integrity.

Question 5

Entity Relationship Diagram (ERD)

Answer 5

Entity Relationship Diagram (ERD) = Depicts the relationship among entities, relational ERD has crows feet symbols
Entities = People, things or transactions
Entity Occurrence = Record
Entity Attribute = Field
Candidate key = All fields that uniquely identify a record
Entity Identifier = Primary key chosen from one of candidate keys

Business Rules = Needed for IT to create relationships. Shows how operations are conducted. 3 rules: Attribute Limitations, Referential Integrity, Cardinality of Relationships

Question 6

Resource, Event, Agent (REA) Diagram

Answer 6

Resource, Event, Agent (REA) Diagram = database modeling tool which is used to teach accounting databases. Not used by IT database designers.

Economic Resource = Good, right, service of value

Economic Event = Occurrence when ownership for a resource is transferred from one person to another (Giving/Taking)
& Economic Commitments
& Business Events = Occurrence when we want to plan, execute, control, monitor or evaluate

Economic Agent = Person/agency who participates in economic event, or is responsible for subordinates participation

Question 7

REA Modeling Steps

Answer 7

Conceptual Data Modeling:

1) Identify the significant events
2) Identify the related resources
3) Identify the related internal and external agents
4) Identify relationships between entities
5) Specify the optionalities and cardinalities of the relationships
6) Identify the attributes of the REA entities

Logical Data Modeling:
7) Design the data repository structure

Process Modeling:
8) Specify the information processes

Development:
9) Complete the physical design and implement

Question 8

REA Ontology

Answer 8

• Four levels of REA detail
  1) Value System Model = exchange between enterprise and external business partners
  2) Value Chain Model = flow of resources between interconnected processes within an enterprise
  3) Business Process Level = focus on business processes and accounting cycles within the value chain
  4) Task Level = focus on workflow, individual detailed tasks necessary to accomplish business events

Question 9

Data Definition Language (DDL)

Answer 9

Data Definition Language (DDL) = Create, alter, drop database objects

Create = Create database objects (Ex. Table/Database) 
Alter = Change the database object (Ex. Add a new field to table) 
Drop = Delete database object (Ex. Delete table, or delete a field)

Question 10

Data Manipulation Language (DML)

Answer 10

Data Manipulation Language (DML) = Used to manipulate data. Select, insert, update and delete database records.

Question 11

Database Modeling

Answer 11

Data Modeling = technique used to develop an anomaly free database with integrity. It uses pictorial representation of the database elements to analyze and design a database.

-Invest 80% of your time designing a database and 20% maintaining it

Question 12

4 Database Integrities

Answer 12

1) Entity Integrity = Each record must have a unique identifier called the primary key. No two records can have same value.
2) Primary Key Integrity = Primary key value cannot be null.
3) Domain Integrity = Values must be from a predefined domain. (Ex. Date is a XX/XX/XX)
4) Referential Integrity = Data referenced and stored in related table must be consistent across database.