# Mapping DSL Examples Complete examples of mapping DSL generation for different domains and data sources. ## Example 1: Relational Database to RDF Mapping ### Source Database Schema ```sql CREATE TABLE person ( person_id INT PRIMARY KEY, first_name VARCHAR(100), last_name VARCHAR(100), email VARCHAR(100), birth_date DATE, company_id INT, FOREIGN KEY (company_id) REFERENCES company(company_id) ); CREATE TABLE company ( company_id INT PRIMARY KEY, company_name VARCHAR(255), industry VARCHAR(100), founded_year INT ); CREATE TABLE employment ( employment_id INT PRIMARY KEY, person_id INT, company_id INT, job_title VARCHAR(100), start_date DATE, salary DECIMAL(10, 2), FOREIGN KEY (person_id) REFERENCES person(person_id), FOREIGN KEY (company_id) REFERENCES company(company_id) ); ``` ### Generated Mapping DSL ```yaml mapping: PersonCompanyMapping version: 1.0 description: Map person and company tables to RDF triples source: type: database connection: postgresql://localhost:5432/company_db dialect: postgresql entities: - mapping_id: PersonMapping table: person entity_type: http://xmlns.com/foaf/0.1/Person identifier: column: person_id datatype: http://www.w3.org/2001/XMLSchema#integer uri_template: "http://example.org/person/{person_id}" properties: - source_column: first_name predicate: http://xmlns.com/foaf/0.1/givenName datatype: xsd:string - source_column: last_name predicate: http://xmlns.com/foaf/0.1/familyName datatype: xsd:string - source_column: email predicate: http://xmlns.com/foaf/0.1/mbox datatype: xsd:string - source_column: birth_date predicate: http://xmlns.com/foaf/0.1/birthday datatype: xsd:date relationships: - name: WORKS_FOR source_column: company_id target_mapping: CompanyMapping predicate: http://schema.org/worksFor cardinality: "*..1" - mapping_id: CompanyMapping table: company entity_type: http://schema.org/Organization identifier: column: company_id datatype: http://www.w3.org/2001/XMLSchema#integer uri_template: "http://example.org/company/{company_id}" properties: - source_column: company_name predicate: http://schema.org/name datatype: xsd:string - source_column: industry predicate: http://schema.org/industry datatype: xsd:string - source_column: founded_year predicate: http://schema.org/foundingDate datatype: xsd:gYear transformation: "year_format" - mapping_id: EmploymentMapping table: employment entity_type: http://example.org/Employment identifier: column: employment_id datatype: http://www.w3.org/2001/XMLSchema#integer uri_template: "http://example.org/employment/{employment_id}" properties: - source_column: job_title predicate: http://schema.org/jobTitle - source_column: start_date predicate: http://schema.org/startDate datatype: xsd:date - source_column: salary predicate: http://example.org/salary datatype: xsd:decimal relationships: - name: HAS_EMPLOYEE source_column: person_id target_mapping: PersonMapping predicate: http://example.org/hasEmployee - name: FOR_COMPANY source_column: company_id target_mapping: CompanyMapping predicate: http://example.org/forCompany ``` ### Generated R2RML ```turtle @prefix rr: . @prefix foaf: . @prefix schema: . @prefix ex: . @prefix xsd: . ex:PersonMapping a rr:TriplesMap ; rr:logicalTable [ rr:tableName "person" ] ; rr:subjectMap [ rr:template "http://example.org/person/{person_id}" ; rr:class foaf:Person ] ; rr:predicateObjectMap [ rr:predicate foaf:givenName ; rr:objectMap [ rr:column "first_name" ] ] ; rr:predicateObjectMap [ rr:predicate foaf:familyName ; rr:objectMap [ rr:column "last_name" ] ] ; rr:predicateObjectMap [ rr:predicate schema:worksFor ; rr:objectMap [ rr:parentTriplesMap ex:CompanyMapping ; rr:joinCondition [ rr:child "company_id" ; rr:parent "company_id" ] ] ] . ex:CompanyMapping a rr:TriplesMap ; rr:logicalTable [ rr:tableName "company" ] ; rr:subjectMap [ rr:template "http://example.org/company/{company_id}" ; rr:class schema:Organization ] ; rr:predicateObjectMap [ rr:predicate schema:name ; rr:objectMap [ rr:column "company_name" ] ] ; rr:predicateObjectMap [ rr:predicate schema:industry ; rr:objectMap [ rr:column "industry" ] ] . ``` --- ## Example 2: CSV File Mapping ### Input CSV File (employees.csv) ```csv employee_id,employee_name,department,manager_id,salary,hire_date E001,Alice Johnson,Engineering,M001,100000,2020-01-15 E002,Bob Smith,Sales,M002,75000,2021-03-20 E003,Carol Davis,Engineering,M001,95000,2020-06-10 E004,David Wilson,HR,M003,80000,2022-01-05 ``` ### Generated Mapping DSL ```yaml mapping: EmployeeCSVMapping version: 1.0 source: type: csv file: data/employees.csv delimiter: "," encoding: utf-8 header_row: 1 skip_blank_rows: true entity: mapping_id: EmployeeMapping entity_type: http://xmlns.com/foaf/0.1/Person identifier: column: employee_id datatype: xsd:string uri_template: "http://example.org/employee/{employee_id}" properties: - source_column: employee_name predicate: http://xmlns.com/foaf/0.1/name datatype: xsd:string - source_column: department predicate: http://example.org/department datatype: xsd:string - source_column: salary predicate: http://example.org/salary datatype: xsd:decimal - source_column: hire_date predicate: http://schema.org/startDate datatype: xsd:date relationships: - name: REPORTS_TO source_column: manager_id target_mapping: ManagerMapping target_entity_type: http://xmlns.com/foaf/0.1/Person target_uri_template: "http://example.org/manager/{manager_id}" predicate: http://example.org/reportsTo cardinality: "*..1" ``` --- ## Example 3: JSON API Response Mapping ### Input JSON API Response ```json { "items": [ { "id": "product_001", "name": "Laptop", "description": "High-performance laptop", "price": 999.99, "currency": "USD", "category": { "id": "cat_001", "name": "Electronics" }, "manufacturer": { "id": "mfg_001", "name": "TechCorp" }, "reviews": [ { "reviewer": "user_123", "rating": 5, "comment": "Excellent product" } ] } ] } ``` ### Generated Mapping DSL ```yaml mapping: ProductAPIMapping version: 1.0 source: type: json location: https://api.example.com/products path: $.items[*] authentication: bearer_token entities: - mapping_id: ProductMapping jsonpath: $. entity_type: http://schema.org/Product identifier: jsonpath: $.id datatype: xsd:string uri_template: "http://example.org/product/{id}" properties: - source_jsonpath: $.name predicate: http://schema.org/name datatype: xsd:string - source_jsonpath: $.description predicate: http://schema.org/description datatype: xsd:string - source_jsonpath: $.price predicate: http://schema.org/price datatype: xsd:decimal - source_jsonpath: $.currency predicate: http://schema.org/priceCurrency datatype: xsd:string relationships: - name: HAS_CATEGORY source_jsonpath: $.category.id target_mapping: CategoryMapping predicate: http://schema.org/category - name: MANUFACTURED_BY source_jsonpath: $.manufacturer.id target_mapping: ManufacturerMapping predicate: http://schema.org/manufacturer - name: HAS_REVIEW source_jsonpath: $.reviews[*].id target_mapping: ReviewMapping predicate: http://schema.org/review - mapping_id: CategoryMapping jsonpath: $.category entity_type: http://schema.org/Category identifier: jsonpath: $.id datatype: xsd:string uri_template: "http://example.org/category/{id}" properties: - source_jsonpath: $.name predicate: http://schema.org/name - mapping_id: ManufacturerMapping jsonpath: $.manufacturer entity_type: http://schema.org/Organization identifier: jsonpath: $.id datatype: xsd:string uri_template: "http://example.org/manufacturer/{id}" properties: - source_jsonpath: $.name predicate: http://schema.org/name ``` --- ## Example 4: Complex Multi-Table Mapping ### Mapping Configuration ```yaml mapping: UniversityMapping version: 1.0 description: Map university database to RDF knowledge graph source: type: database connection: mysql://localhost/university entities: # Student Mapping - mapping_id: StudentMapping table: students entity_type: http://example.org/Student identifier: column: student_id uri_template: "http://example.org/student/{student_id}" properties: - source_column: first_name predicate: foaf:givenName - source_column: last_name predicate: foaf:familyName - source_column: email predicate: foaf:mbox - source_column: enrollment_date predicate: schema:startDate datatype: xsd:date relationships: - name: ENROLLED_IN source_column: degree_program_id target_mapping: DegreeMapping predicate: ex:enrolledIn - name: ADVISED_BY source_column: advisor_id target_mapping: ProfessorMapping predicate: ex:advisedBy # Professor Mapping - mapping_id: ProfessorMapping table: professors entity_type: http://example.org/Professor identifier: column: professor_id uri_template: "http://example.org/professor/{professor_id}" properties: - source_column: name predicate: foaf:name - source_column: email predicate: foaf:mbox - source_column: office predicate: ex:office relationships: - name: TEACHES source_column: department_id target_mapping: DepartmentMapping predicate: ex:partOf # Course Mapping - mapping_id: CourseMapping table: courses entity_type: http://schema.org/Course identifier: column: course_id uri_template: "http://example.org/course/{course_id}" properties: - source_column: course_name predicate: schema:name - source_column: description predicate: schema:description - source_column: credit_hours predicate: ex:creditHours datatype: xsd:integer relationships: - name: OFFERED_BY source_column: department_id target_mapping: DepartmentMapping predicate: ex:offeredBy # Degree Program Mapping - mapping_id: DegreeMapping table: degree_programs entity_type: http://schema.org/EducationalOccupationalCredential identifier: column: degree_id uri_template: "http://example.org/degree/{degree_id}" properties: - source_column: degree_name predicate: schema:name - source_column: duration_years predicate: ex:duration datatype: xsd:integer # Department Mapping - mapping_id: DepartmentMapping table: departments entity_type: http://schema.org/Organization identifier: column: department_id uri_template: "http://example.org/department/{department_id}" properties: - source_column: department_name predicate: schema:name - source_column: building predicate: ex:location ``` --- ## Mapping Statistics | Example | Source | Entities | Properties | Relationships | Output Formats | |---------|--------|----------|-----------|----------------|----------------| | Database | SQL | 3 (Person, Company, Employment) | 12 | 5 | DSL, R2RML | | CSV | File | 1 (Employee) | 5 | 1 | DSL | | JSON API | HTTP | 4 (Product, Category, Manufacturer, Review) | 8 | 3 | DSL | | University | SQL | 5 (Student, Professor, Course, Degree, Dept) | 16 | 6 | DSL | --- See [mapping-patterns.md](../references/mapping-patterns.md) for detailed mapping DSL design patterns.