Duality
Links increment (E+) and decrement (E-) economic events
Stockflow
Links economic events and resources or resource types
Participation
Links economic events and agents.
Custody
Links Agents and Resources such that agent has physical control over the resource or controls access to the resource
Assignment
Links Internal Agent to External Agent
Responsibility
Links internal agent to internal agent.
Typical Resource to economic event
Resource Type 1..
-0..
Economic event
Typical Resource to economic event for custom made goods
Resource Type 1..*-0..1 Economic Event
Typical economic event to agent
economic event0..*-1..1Agent
Economic Increment Event
Purchase (receipt of goods)
Rental, Service Acquisition, if services or utilities are acquired
Economic Decrement Event
Cash Disbursement
Resource/Resource Type: Cash
Entity Integrity
A primary key in a table must not contain a null value
Referential Integrity
A value for a foreign key in a table must either-Be null (no data value - note that this is not a zero)-Match exactly a value for the primary key in the table from which it was posted
Fact Rule" = "One Fact, One Place
...
Fact
a pairing of a primary key attribute value (or a potential primary key attribute value) with another attribute value
Maximum Multiplicities
The general rule is when a class has a maximum multiplicity of "many" the table for that class should not have a foreign key. Avoids redundancy
Minimum Multiplicities
If a class has mandatory participation and "at most one" participation, the table for that class will have a foreign key (unless the other class has the same multiplicities). This avoids null values in the foreign key column
many to many
separate table
If a class has mandatory participation and ...... participation, the table for that class will have a foreign key
at most one"
Do NOT make a separate table�Redundancy is avoided and load is not an issue (it is 100% load) if you follow this instruction
0..1 foreign key or association table?
General rule: make foreign keys when that decision results in high load