# Constraint Generation Examples Complete constraint examples for different domains. ## Example 1: University Domain Constraints ### Schema Definition ``` Entities: Student: student_id (unique), name (required), email (unique) Professor: professor_id (unique), name (required) Course: course_code (unique), title (required), credits Department: dept_id (unique), name (required) Relationships: (Student)-[:ENROLLED_IN]->(Course): min 1, max 10 (Professor)-[:TEACHES]->(Course): min 1, max 5 (Department)-[:MANAGES]->(Course): min 0, max unlimited (Department)-[:EMPLOYS]->(Professor): min 1 ``` ### Generated Neo4j Constraints ```cypher -- Unique Constraints CREATE CONSTRAINT student_id_unique ON (s:Student) REQUIRE s.student_id IS UNIQUE CREATE CONSTRAINT professor_id_unique ON (p:Professor) REQUIRE p.professor_id IS UNIQUE CREATE CONSTRAINT course_code_unique ON (c:Course) REQUIRE c.course_code IS UNIQUE CREATE CONSTRAINT dept_id_unique ON (d:Department) REQUIRE d.dept_id IS UNIQUE CREATE CONSTRAINT student_email_unique ON (s:Student) REQUIRE s.email IS UNIQUE -- Indexes CREATE INDEX ON (s:Student)(name) CREATE INDEX ON (p:Professor)(name) CREATE INDEX ON (c:Course)(title) CREATE INDEX ON (d:Department)(name) -- Validation Queries MATCH (s:Student) WHERE s.name IS NULL RETURN s -- Should be empty MATCH (c:Course) WHERE c.title IS NULL RETURN c -- Should be empty MATCH (s:Student) WHERE NOT (s)-[:ENROLLED_IN]->() RETURN s -- Check min enrollment ``` ### Generated SHACL Shapes ```turtle @prefix ex: . @prefix sh: . @prefix xsd: . ex:StudentShape a sh:NodeShape ; sh:targetClass ex:Student ; sh:property [ sh:path ex:student_id ; sh:minCount 1 ; sh:maxCount 1 ] ; sh:property [ sh:path ex:name ; sh:datatype xsd:string ; sh:minCount 1 ] ; sh:property [ sh:path ex:email ; sh:datatype xsd:string ; sh:minCount 1 ; sh:pattern "^[^@]+@[^@]+\\.[^@]+$" ] ; sh:property [ sh:path ex:enrolledIn ; sh:class ex:Course ; sh:minCount 1 ; sh:maxCount 10 ] . ex:ProfessorShape a sh:NodeShape ; sh:targetClass ex:Professor ; sh:property [ sh:path ex:professor_id ; sh:minCount 1 ] ; sh:property [ sh:path ex:name ; sh:datatype xsd:string ; sh:minCount 1 ] ; sh:property [ sh:path ex:teaches ; sh:class ex:Course ; sh:minCount 1 ; sh:maxCount 5 ] . ``` --- ## Example 2: E-Commerce Domain Constraints ### Schema Definition ``` Entities: Customer: customer_id (unique), email (unique), name (required) Product: product_id (unique), sku (unique), price > 0 Order: order_id (unique), total > 0 Category: category_id (unique), name (required) Relationships: (Customer)-[:PLACES]->(Order): min 0, max unlimited (Order)-[:CONTAINS]->(Product): min 1, max 1000 (Product)-[:BELONGS_TO]->(Category): min 1, max 1 ``` ### Generated Neo4j Constraints ```cypher -- Unique Constraints CREATE CONSTRAINT customer_id_unique ON (c:Customer) REQUIRE c.customer_id IS UNIQUE CREATE CONSTRAINT email_unique ON (c:Customer) REQUIRE c.email IS UNIQUE CREATE CONSTRAINT product_id_unique ON (p:Product) REQUIRE p.product_id IS UNIQUE CREATE CONSTRAINT sku_unique ON (p:Product) REQUIRE p.sku IS UNIQUE CREATE CONSTRAINT order_id_unique ON (o:Order) REQUIRE o.order_id IS UNIQUE CREATE CONSTRAINT category_id_unique ON (cat:Category) REQUIRE cat.category_id IS UNIQUE -- Data Type Validation Queries MATCH (p:Product) WHERE p.price <= 0 RETURN p -- Should be empty MATCH (o:Order) WHERE o.total <= 0 RETURN o -- Should be empty MATCH (c:Customer) WHERE c.name IS NULL RETURN c -- Should be empty -- Relationship Validation Queries MATCH (p:Product) WHERE NOT (p)-[:BELONGS_TO]->() RETURN p -- All products must have category MATCH (o:Order) WHERE NOT (o)-[:CONTAINS]->() RETURN o -- All orders must contain items ``` --- ## Example 3: RDF/OWL Constraints ### SHACL Shapes ```turtle @prefix ex: . @prefix foaf: . @prefix sh: . @prefix xsd: . ex:ResearcherShape a sh:NodeShape ; sh:targetClass ex:Researcher ; sh:nodeKind sh:IRI ; sh:property [ sh:path foaf:name ; sh:minCount 1 ; sh:datatype xsd:string ] ; sh:property [ sh:path foaf:email ; sh:minCount 1 ; sh:pattern "^[^@]+@[^@]+\\.[^@]+$" ] ; sh:property [ sh:path ex:writes ; sh:class ex:Paper ; sh:minCount 1 ] . ex:PaperShape a sh:NodeShape ; sh:targetClass ex:Paper ; sh:property [ sh:path ex:title ; sh:minCount 1 ; sh:datatype xsd:string ; sh:minLength 5 ] ; sh:property [ sh:path ex:writtenBy ; sh:class ex:Researcher ; sh:minCount 1 ; sh:maxCount 10 ] ; sh:property [ sh:path ex:publicationYear ; sh:datatype xsd:gYear ; sh:minInclusive "2000"^^xsd:gYear ] . ``` --- ## Example 4: Social Network Constraints ### Constraint Specification ``` User: user_id (unique), username (unique), email (unique) Post: post_id (unique), content (required), created_date (required) Comment: comment_id (unique), text (required) Cardinality: - User can FOLLOW many users - User can CREATE many posts (no max) - Post can HAVE_COMMENT many (no max) - Comment has exactly 1 author (min 1, max 1) ``` ### Generated Constraints ```cypher -- Unique Constraints CREATE CONSTRAINT user_id_unique ON (u:User) REQUIRE u.user_id IS UNIQUE CREATE CONSTRAINT username_unique ON (u:User) REQUIRE u.username IS UNIQUE CREATE CONSTRAINT email_unique ON (u:User) REQUIRE u.email IS UNIQUE CREATE CONSTRAINT post_id_unique ON (p:Post) REQUIRE p.post_id IS UNIQUE CREATE CONSTRAINT comment_id_unique ON (c:Comment) REQUIRE c.comment_id IS UNIQUE -- Required Property Validation MATCH (p:Post) WHERE p.content IS NULL OR p.created_date IS NULL RETURN p MATCH (c:Comment) WHERE c.text IS NULL RETURN c -- Relationship Validation MATCH (c:Comment) WHERE NOT (c)<-[:AUTHORED_BY]-(u:User) RETURN c -- All comments need author ``` ### SHACL Format ```turtle ex:UserShape a sh:NodeShape ; sh:targetClass ex:User ; sh:property [ sh:path ex:follows ; sh:class ex:User ] . ex:PostShape a sh:NodeShape ; sh:targetClass ex:Post ; sh:property [ sh:path ex:content ; sh:minCount 1 ; sh:datatype xsd:string ; sh:minLength 1 ] ; sh:property [ sh:path ex:createdDate ; sh:minCount 1 ; sh:datatype xsd:dateTime ] . ex:CommentShape a sh:NodeShape ; sh:targetClass ex:Comment ; sh:property [ sh:path ex:text ; sh:minCount 1 ; sh:datatype xsd:string ] ; sh:property [ sh:path ex:authoredBy ; sh:class ex:User ; sh:minCount 1 ; sh:maxCount 1 ] . ``` --- ## Constraint Comparison Table | Domain | Unique | Required | Relationships | Cardinality | Type | |--------|--------|----------|---------------|-------------|------| | University | 4 | 3 | 4 | 4 constraints | Mixed | | E-Commerce | 6 | 1 | 3 | 3 constraints | Mixed | | Research | 0 | 3 | 2 | 3 constraints | SHACL | | Social | 5 | 2 | 3 | 2 constraints | Cypher | --- See [constraint-patterns.md](../references/constraint-patterns.md) for detailed constraint patterns and best practices.