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#+TITLE: Domino Features & Roadmap
* Extended Relational Model (RM/T)
:PROPERTIES:
:CATEGORY: semantic-modeling
:END:
An extended relational database engine based on E. F. Codd's RM/T (1979).
Captures more meaning through entity types, surrogates, and molecular semantics.
** Implemented Features
*** DONE Content-Addressed Storage
CLOSED: [2025-01-21]
- [X] SHA-256 surrogates for all entities
- [X] System-controlled entity identifiers (E-domain)
- [X] Automatic deduplication via content addressing
- [X] Immutable data structures
*** DONE Entity Types (E-Relations)
CLOSED: [2025-01-21]
- [X] Kernel entity types (database, relation)
- [X] E-relations for entity existence assertion
- [X] Surrogate-based entity identification
- [X] Entity integrity enforcement
*** DONE Property Relations (P-Relations)
CLOSED: [2025-01-21]
- [X] Immediate property storage
- [X] Single-valued property support
- [X] Property integrity (Rule 4)
- [X] Foreign key references via surrogates
*** DONE Merkle Tree Integration
CLOSED: [2025-01-21]
- [X] Relations as Merkle trees
- [X] Database state versioning
- [X] Efficient state diffing
- [X] Content-addressed relation hashing
*** DONE Volcano Iterator Model
CLOSED: [2025-01-21]
- [X] Lazy tuple evaluation
- [X] Process-based iterators
- [X] Message-passing protocol
- [X] Memory-bounded queries
*** DONE Transactional Operations
CLOSED: [2025-01-21]
- [X] ACID guarantees via Mnesia
- [X] Atomic tuple insertion
- [X] Tuple retraction with transactions
- [X] Relation clear and retract operations
*** DONE Comprehensive Test Suite
CLOSED: [2025-01-21]
- [X] Database creation tests
- [X] Relation and tuple operations
- [X] Hash consistency validation
- [X] Iterator protocol tests
- [X] Retraction and truncate tests
** Planned RM/T Extensions
*** TODO Characteristic Entities
Multi-valued properties as subordinate entities.
- [ ] Characteristic entity types (C-relations)
- [ ] Characteristic graph (CG-relation)
- [ ] Characteristic tree hierarchy
- [ ] Characteristic integrity (Rule 5)
- [ ] Example: Job history as characteristic of Employee
*** TODO Associative Entities
Relationships as first-class entities with properties.
- [ ] Associative entity types (A-relations)
- [ ] Association graph (AG-relation)
- [ ] Association integrity (Rule 6)
- [ ] Higher-order associations
- [ ] Example: Assignment(employee, project, start_date)
*** TODO Generalization Hierarchies
Entity subtyping and inheritance.
- [ ] Unconditional gen inclusion (UGI-relation)
- [ ] Alternative gen inclusion (AGI-relation)
- [ ] Subtype integrity (Rule 7)
- [ ] Property inheritance
- [ ] Multiple inheritance support
- [ ] Example: Engineer/Secretary/Trucker subtypes of Employee
*** TODO Cover Aggregation
Collections and groupings.
- [ ] Cover membership relation (KG-relation)
- [ ] Cover entity types
- [ ] Dynamic membership
- [ ] Heterogeneous covers
- [ ] Example: Convoys, Teams, Departments
*** TODO Event Precedence
Temporal ordering and scripts.
- [ ] Event entity types (T-relations)
- [ ] Unconditional successor (US-relation)
- [ ] Alternative successor (AS-relation)
- [ ] Unconditional predecessor (UP-relation)
- [ ] Alternative predecessor (AP-relation)
- [ ] Example: Order → Shipment → Invoice
*** TODO Extended Operators
Operators for molecular semantics.
- [ ] OUTER NATURAL JOIN
- [ ] OUTER UNION
- [ ] OUTER THETA-JOIN
- [ ] MAYBE operators (null handling)
- [ ] Graph operators (OPEN, CLOSE, STEP)
*** TODO RM/T Catalog
Extensible schema catalog.
- [ ] CATR (relations catalog)
- [ ] CATRA (relation-attribute)
- [ ] CATA (attributes catalog)
- [ ] CATAD (attribute-domain)
- [ ] CATD (domains catalog)
- [ ] CATC (categories catalog)
- [ ] CATRC (relation-category)
*** TODO Property Graph (PG-relation)
Link P-relations to E-relations.
- [ ] Property molecule types
- [ ] Dynamic property schema
- [ ] Property graph traversal
** Classical Relational Algebra
*** TODO Selection (σ)
Filter tuples by predicate.
- [ ] THETA-SELECT with comparison operators
- [ ] Support for <, ≤, =, ≥, >, ≠
- [ ] TRUE and MAYBE versions (null handling)
*** TODO Projection (π)
Project relation onto subset of attributes.
- [ ] Remove specified columns
- [ ] Eliminate duplicate rows
- [ ] Preserve set semantics
*** TODO Cartesian Product (×)
Cross product of two relations.
- [ ] Unrestricted concatenation
- [ ] Basis for joins
*** TODO Natural Join (⋈)
Join on common attributes.
- [ ] Equi-join with duplicate removal
- [ ] Used in normalization
*** TODO Theta Join (⋈θ)
Join with arbitrary comparison.
- [ ] Support all theta operators
- [ ] Generalizes natural join
*** TODO Union (∪)
Set union of compatible relations.
- [ ] Union-compatible constraint
- [ ] Duplicate removal
*** TODO Intersection (∩)
Set intersection.
- [ ] Union-compatible constraint
*** TODO Difference (−)
Set difference.
- [ ] Union-compatible constraint
*** TODO Divide (÷)
Relational division.
- [ ] Algebraic universal quantifier
*** TODO Rename (ρ)
Attribute renaming.
- [ ] Enable self-joins
** Advanced Features
*** TODO Null Value Handling
Three-valued logic for incomplete information.
- [ ] "Value unknown" null type
- [ ] "Property inapplicable" null type
- [ ] E-null for "entity unknown"
- [ ] Null substitution principle
- [ ] MAYBE operators
*** TODO Infinite Relations (Aleph₀)
Countably infinite relation generators.
- [ ] Integer generator
- [ ] Arithmetic relations (plus, minus, multiply)
- [ ] Lazy evaluation with constraints
- [ ] Partially materialized storage
- [ ] User-defined generators
*** TODO View Integration
Merging multiple perspectives.
- [ ] View definition language
- [ ] Automatic view maintenance
- [ ] View update translation
*** TODO Temporal Support
Time-varying databases.
- [ ] Transaction time
- [ ] Valid time
- [ ] Bitemporal support
- [ ] Non-forgetting mode
*** TODO Distributed Synchronization
Merkle tree-based replication.
- [ ] Efficient diff protocol
- [ ] Conflict resolution
- [ ] Eventual consistency
** Developer Experience
*** TODO Query Language
High-level relational query language.
- [ ] Algebraic syntax
- [ ] Tuple calculus variant
- [ ] Domain calculus variant
*** TODO REPL Console
Interactive query environment.
- [ ] Live query evaluation
- [ ] Schema introspection
- [ ] Query history
*** TODO Visualization Tools
Graphical representation.
- [ ] Relation browser
- [ ] Join graph visualization
- [ ] Generalization hierarchy diagrams
- [ ] Query execution plans
*** TODO Org Babel Integration
Literate programming support.
- [ ] Execute relational queries in org-mode
- [ ] Export results to tables
- [ ] Reproducible analysis
** Documentation & Validation
*** DONE Code Documentation
CLOSED: [2025-01-21]
- [X] Module architecture overview
- [X] Data structure specifications
- [X] Usage examples
- [X] Implementation details
*** TODO Theoretical Validation
Ensure correctness.
- [ ] Formal proofs of operator properties
- [ ] Closure verification
- [ ] Idempotence tests
- [ ] Property-based testing with PropEr
- [ ] Comparison with Date & Darwen semantics
*** TODO Research Papers
Link to foundational theory.
- [ ] Codd 1970: "A Relational Model"
- [ ] Codd 1979: "Extending the Database Relational Model" (RM/T)
- [ ] Codd 1985: "Does AlOL Need the Relational Algebra?"
- [ ] Date & Darwen: "Foundation for Future Database Systems"
** References
- E. F. Codd (1979). "Extending the Database Relational Model to Capture More Meaning"
- E. F. Codd (1970). "A Relational Model of Data for Large Shared Data Banks"
- C. J. Date & Hugh Darwen. "Foundation for Future Database Systems: The Third Manifesto"
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