Skip to content

Latest commit

 

History

History
147 lines (100 loc) · 3.07 KB

DSL.md

File metadata and controls

147 lines (100 loc) · 3.07 KB

dbdia DSL reference

This document provides a summary of the domain-specific language recognized by dbdia to define relational schemas and ER models (you may also have a look at the actual ANTLR grammar in use).

General aspects

Comments

C-style comments can be used.

... // single-line comment 

/*
 multi-line 
 comment 
*/

Identifiers

ID: 
    [Alpha] ((Alpha|Digit|\_)*(Alpha|Digit))?

Notes:

  • You can use Unicode letters with accents.
  • The underscore can not be used as a beggining or end character (versions 0.4 or higher).

Semantic checks

dbdia performs a few semantic checks:

  • You can not define the same symbol twice at the same level of scoping. An error is issued if you try to define two entities/relationships with the same name in an ER model, and similary for tables in relational schemas, fields in tables or entities, etc.
  • You can not make a reference to an undefined symbol. Forward references are allowed though.

Relational schemas

relationalSchema: 
    tableDefinition*

tableDefinition: 
    'table' name_of_table=ID '(' tableField (',' tableField)* ')'

tableField: 
    (primaryKeyFieldDef | optionalFieldDef | plainFieldDef)  
    type_identifier=ID?              // optional identifier for field type
    ('-->' table=ID '.' field=ID)?   // optional foreign key reference 
  
primaryKeyFieldDef:
    '_' name=ID '_' 

optionalFieldDef: // for optional (i.e. nullable) fields
    name=ID '?'     

plainFieldDef: 
    name=ID

Basic example

ER models

entRelModel: 
  entRelModelItem*
  
entRelModelItem: 
    entity          // Entity type
  | relationship    // Relationship
  | weakEntity      // Weak entity type

Entitity types

entity: 
  name=ID '(' fields=(entityField (',' entityField)*)? ')'
  
entityField : 
    keyField
  | nonKeyField
  
nonKeyField:
    simpleField
  | optionalField
  | derivedField
  | compositeField
  | multivalueField
  
keyField: 
    '_' name=ID '_' 
    
simpleField: 
    name=ID
    
optionalField: 
    name=ID '?'
  
derivedField:
    '.' name=ID '.'
  
compositeField : 
    name=ID '(' subfields=(nonKeyField (',' nonKeyField )*) ')'  
  
multivalueField: 
    '{' (simpleField | compositeField) '}'

Basic example

Relationships

relation: 
  entityA=ID 
  constrA=relationshipConstraints
  '<' name=ID ('(' nonKeyField (',' nonKeyField)* ')')? '>' 
  constrB=relationConstraints 
  entityB=ID
  
relationshipConstraints:
    '-'+ ('1' | 'M' | 'N') '-'+  // '-' indicates partial participation
  | '='+ ('1' | 'M' | 'N') '='+  // '=' indicates total participation

Basic example

Weak entitity types

weakEntity: 
    name_of_identifying_entity=ID 
    ('-'+ | '='+)      // parcial or total participation by identifying entity 
    '<<' name_of_identifying_relationship=ID '>>'    
    weak_entity=entity // the actual weak entity type (defined like an entity type)

Basic example