Language Features for Re-Use and Maintainability of MDA Transformations Michael Lawley, Keith Duddy, Anna Gerber, Kerry Raymond

Styles of transformation Source-driven Organized by source model concept Target-driven Organized by target model concept Aspect-driven Organized by conceptual relationship between source and target models, eg inheritance, containment

Source-driven

Organized by source model concept

Target-driven

Organized by target model concept

Aspect-driven

Organized by conceptual relationship between source and target models, eg inheritance, containment

Rules may be reused in two ways: Rule Extension Allows Additional clauses to be added to source match Additional model elements to be created in target Rule Overriding Allows Additional clauses to be added to match Overriding the superseded rule to apply a different target expression to the original rule

Rules may be reused in two ways:

Rule Extension Allows

Additional clauses to be added to source match

Additional model elements to be created in target

Rule Overriding Allows

Additional clauses to be added to match

Overriding the superseded rule to apply a different target expression to the original rule

Indirect rule coupling Tracking Classes are MOF Classes their instances relate source extent elements to target extent elements and are created because of a rule match may be used in the source term of a rule to “query” target model elements “created” by other rules

Tracking Classes are MOF Classes

their instances relate source extent elements to target extent elements and are created because of a rule match

may be used in the source term of a rule to “query” target model elements “created” by other rules

Mappings between UML, DL, OWL and ER

Example: UML and DL TRANSFORMATION UML2DL(uml,dl) RULE Assoc2Role (a,r) FORALL UMLAssoc a MAKE DLRole r SET r.uniqueID = a.name; RULE Attr2Role (a,r) FORALL UMLAttr a MAKE DLRole r SET r.uniqueID = a.name LINKING RoleForAttr WITH attr = a, role = r; RULE Class2Concept(c1,c2) FORALL UMLClass c1 MAKE DLConcept c2 SET c2.uniqueID = c1.name; TRANSFORMATION DL2UML(dl,uml) RULE Role2Assoc(r,a) FORALL DLRole r MAKE UMLAssoc a SET a.name = r.uniqueID; RULE Concept2Class(c1,c2) FORALL DLConcept c1 MAKE UMLCLass c2 SET c2.name = c1.uniqueID;

TRANSFORMATION UML2DL(uml,dl)

RULE Assoc2Role (a,r)

FORALL UMLAssoc a

MAKE DLRole r

SET r.uniqueID = a.name;

RULE Attr2Role (a,r)

FORALL UMLAttr a

MAKE DLRole r

SET r.uniqueID = a.name

LINKING RoleForAttr

WITH attr = a, role = r;

RULE Class2Concept(c1,c2)

FORALL UMLClass c1

MAKE DLConcept c2

SET c2.uniqueID = c1.name;

TRANSFORMATION DL2UML(dl,uml)

RULE Role2Assoc(r,a)

FORALL DLRole r

MAKE UMLAssoc a

SET a.name = r.uniqueID;

RULE Concept2Class(c1,c2)

FORALL DLConcept c1

MAKE UMLCLass c2

SET c2.name = c1.uniqueID;

Example: ER and DL TRANSFORMATION ER2DL(er,dl) RULE Relationship2Role(r1,r2) FORALL ERRelationship r1 MAKE DLRole r2 SET r2.uniqueID = r1.name; RULE Attribute2Role(a,r) FORALL ERAttribute a MAKE DLRole r SET r.uniqueID = a.name; RULE Entity2Concept(e,c) FORALL EREntity e MAKE DLConcept c SET c.uniqueID = e.name; TRANSFORMATION DL2ER(dl,er) RULE Role2Relationship(r1,r2) FORALL DLRole r1 MAKE ERRelationship r2 SET r2.name = r1.uniqueID; RULE Concept2Entity (c,e) FORALL DLConcept c MAKE EREntity e SET e.name = c.uniqueID;

TRANSFORMATION ER2DL(er,dl)

RULE Relationship2Role(r1,r2)

FORALL ERRelationship r1

MAKE DLRole r2

SET r2.uniqueID = r1.name;

RULE Attribute2Role(a,r)

FORALL ERAttribute a

MAKE DLRole r

SET r.uniqueID = a.name;

RULE Entity2Concept(e,c)

FORALL EREntity e

MAKE DLConcept c

SET c.uniqueID = e.name;

TRANSFORMATION DL2ER(dl,er)

RULE Role2Relationship(r1,r2)

FORALL DLRole r1

MAKE ERRelationship r2

SET r2.name = r1.uniqueID;

RULE Concept2Entity (c,e)

FORALL DLConcept c

MAKE EREntity e

SET e.name = c.uniqueID;

Example: UML and DL extended TRANSFORMATION DLfromOWL2UML(dl,owl2dl,uml) EXTENDS DL2UML(dl,uml) RULE Role2Attr(r,a) OVERRIDES Role2Assoc(r,a) FORALL PropForRole@owl2dl pr WHERE pr.role = r AND pr.prop = p AND OWLDataTypeProperty p MAKE UMLAttribute a FROM r SET a.name = r.uniqueID; LINKING RoleForAttr WITH attr = a, role = r;

TRANSFORMATION DLfromOWL2UML(dl,owl2dl,uml)

EXTENDS DL2UML(dl,uml)

RULE Role2Attr(r,a)

OVERRIDES Role2Assoc(r,a)

FORALL PropForRole@owl2dl pr

WHERE pr.role = r AND pr.prop = p

AND OWLDataTypeProperty p

MAKE UMLAttribute a FROM r

SET a.name = r.uniqueID;

LINKING RoleForAttr

WITH attr = a, role = r;

Example: ER and DL extended TRANSFORMATION DLfromUML2ER(dl,uml2dl,er) EXTENDS DL2ER(dl,er) RULE Role2Attribute_fromUML(r,a) OVERRIDES Role2Relationship(r,rel) FORALL RoleForAttr@uml2dl ra WHERE ra.role = r MAKE ERAttribute a FROM r SET a.name = r.uniqueID;

TRANSFORMATION DLfromUML2ER(dl,uml2dl,er)

EXTENDS DL2ER(dl,er)

RULE Role2Attribute_fromUML(r,a)

OVERRIDES Role2Relationship(r,rel)

FORALL RoleForAttr@uml2dl ra

WHERE ra.role = r

MAKE ERAttribute a FROM r

SET a.name = r.uniqueID;

The Simple UML Model

The Simple Relational Model

The Mapping (Tracking) Model

UML RDBMS TableForClass N: String ObjRelTX C 1 C 1 A 1 Col 1 T 1 Class Attribute ColumnFor ContainedAttr Column Table

1. A class maps on to a single table Issues not considered in the description: Only "persistent" UML Classes should be mapped How should key columns be named? We choose the name of the Class RULE Class2Table(c, t, k) FORALL UMLClass c WHERE c.kind = "persistent" MAKE Table t, Key k SET t.name = c.name, t.key = k, k.name = c.name LINKING TableForClass WITH cls = c, tbl = t LINKING KeyForClass WITH cls = c, key = k;

Issues not considered in the description:

Only "persistent" UML Classes should be mapped

How should key columns be named? We choose the name of the Class

RULE Class2Table(c, t, k)

FORALL UMLClass c

WHERE c.kind = "persistent"

MAKE Table t, Key k

SET t.name = c.name, t.key = k,

k.name = c.name

LINKING TableForClass

WITH cls = c, tbl = t

LINKING KeyForClass

WITH cls = c, key = k;

Non-extension style for Attr2Col Rule RULE Attr2Column(c, a, t, col, t4c) FORALL Attribute a WHERE TableForClass t4c LINKS cls = c, tbl = t AND hasAttr(c, a, n) MAKE Column col FROM colName(n) SET col.name = n, col.owner = t, t4c.cols = col LINKING ColumnForContainedAttr WITH cls = c, attr = a, name = n, col = col;

RULE Attr2Column(c, a, t, col, t4c)

FORALL Attribute a

WHERE TableForClass t4c

LINKS cls = c, tbl = t

AND hasAttr(c, a, n)

MAKE Column col FROM colName(n)

SET col.name = n,

col.owner = t,

t4c.cols = col

LINKING ColumnForContainedAttr

WITH cls = c, attr = a,

name = n, col = col;

% Immediate Attributes of a Class that are % primary have their corresponding Column % as part of the Table's Key. RULE KeyColumns(c, a, k, col) WHERE ColumnForContainedAttr LINKS cls = c, attr = a, col = col AND a.kind = "primary" AND inhAttr(c, a) SET col.belongsTo = k;

% Immediate Attributes of a Class that are

% primary have their corresponding Column

% as part of the Table's Key.

RULE KeyColumns(c, a, k, col)

WHERE ColumnForContainedAttr

LINKS cls = c, attr = a, col = col

AND a.kind = "primary" AND inhAttr(c, a)

SET col.belongsTo = k;

% Produce a Column and a ForeignKey for every % Association. RULE ColumnAndForeignKeyForAssoc(assoc, tbl, key) FORALL Association assoc WHERE TableForClass LINKS class = assoc.source, table = tbl AND KeyForClass LINKS class = assoc.destination, key = key MAKE Column col, ForeignKey fk SET col.name = assoc.name, col.owner = tbl, fk.owner = tbl, fk.column = col, fk.refersTo = key LINKING ColumnForAssociation WITH assoc = assoc, col = col, fkey = fk;

% Produce a Column and a ForeignKey for every

% Association.

RULE ColumnAndForeignKeyForAssoc(assoc, tbl, key)

FORALL Association assoc

WHERE TableForClass

LINKS class = assoc.source, table = tbl

AND KeyForClass

LINKS class = assoc.destination, key = key

MAKE Column col, ForeignKey fk

SET col.name = assoc.name, col.owner = tbl,

fk.owner = tbl, fk.column = col,

fk.refersTo = key

LINKING ColumnForAssociation

WITH assoc = assoc, col = col, fkey = fk;