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Data Modelling Tutor - To Do

Recent Changes

• Unnamed relationships included in the HTML view
• generate foreign keys for 1 to 0-1 relationships
• quote field names to bring in line with MyPHPAdmin export and protect reserved words (option controlled by attribute in model)
• 1 to 0-1 relationships generate Fks correctly - 1-1 - author needs to decide and change to 1 - 0-1
• Generate enum datatype in the SQL
• Form to enter model URI
• output method set dynamically to generate text or XML instead of HTML
• Improved interface
• Rules for derived attributes added
• Entity comments were missing - fixed
• Added rule element to attributes and relationships - rendered in Text and HTML view, included in schema
• unit tests - some done
• transformation to DROP TABLES : not in dependency order
• default name for link tables corrected to use _
• relationships with attributes - supported in EAR ,DDL and HTML and in Schema
• Subtypes supported in ER models and HTML but not yet in DDL
• Transform to HTML
• Changed to POST
• DDL extended generation now does primary keys for an entity if none defined, and better SQL
• Derive data model from non-normalized data source - see normalizer.xq
• Derived attributes and relationship annotated with leading / in diagram
• supporting entities as types to simplify relationships - only in ER diagrams
• Inactive links in Navigation bar greyed rather than removed
• crows foot replaces the closed triangle for many, now I know about arrow syntax - tee not working
• refactored er.xqm putting string handling in ws.xqm
• ER diagrams show attributes in the box
• primarykey, derived, autioincrement changed to xs:boolean in schema
• derived attribute added to entity and attribute
• attributes with the same name in diifferent entities are distinguished in the diagrams
• Handle involuted relationships in comparison
• Integrity errors inhibit model comparison,and unchanged input detected to forestall eager answer viewing

Bugs

• 1-1 - author needs to decide and change to 1 - 0-1 - add to documentation and model check
• rename title in enum to label
• Types which are the same name as entities are treated as relationships - but this is not documented and code not yet generated
• One to many relationships should set foreign key to NOT NULL
• Derived relationship not annoted with /
• Schema is too tight - no ordering constraints needed
• Comments should allow HTML in the schema - handled OK in the HTML view
• rename Worksheet/Name to Worksheet/Title for consistency
• Dependent keys not included in the Text
• Dot interface to graphviz must use POST not GET - generate SVG or handle as streamed binary

Worksheets Roadmap

• Examples needed for enums; dependent in role and foreign keys as primary keys; many-many relationships; unique; subtypes; multi-valued attributes; attribute entity types
• Need to diagnose the problems arising in the CW and exam and incorporate into the worksheets
• Examples o one- one relationships where there is a conceptual difference - support optimisation to one table

Application Roadmap

• Model comparator
  • relationships in input but not in answer are not detected
  • no comparision of data types in analysis
  • Improve fuzzy matching - work in lower case domain
  • Match without replacement: Entity and Attribute matching must be unique - currrent algorithm allows a model answer attribute to be matched with two different attempt attributes.
  • Use stemming to allow better detection of plurals
  • Need to allow some model aspects to be optional eg. with or without primary keys
  • Compare entities by attribute names - needed for normalizer output comparison
• Model schema
  • detect duplicate entity/attribute within entity, types - check function does this - added to the interface - Done may 09
  • support embedded entities as well as dependent entities (poorly explained)
  • support units in a datatype for explict documentation
  • drop datatype and type distinction - use type only and its name if no type defined in model
  • support enumerated types for type as well as datatype
  • drop datatype from attribute and allow only in type
  • support type definition with name, size and decimals
  • Drop many and optional from code - just use the min and max (or make many mean 0 to N )
  • Handle numeric values in min and max
  • Use the schema to validate the model - currently unnecessarily strict
  • Support subtypes in the model XML - support for ER diagram, text and HTML only at present
  • allow short tags - e, a r, t ?
  • handle multi-valued attributes
  • entity prefixes
  • Comment needs to be text or HTML
  • Support entity types as relationships
  • support sequence
  • support xs types, minLength and maxLength and mapping to MySQL data types
• Modeller interface
  • Selecting a Mode should trigger re-display in modeller.xq (modeller deprecated)
  • Put output in a tab with DHTML
  • Save modified model and save generated DDL to a file - not needed
  • use Ajax to update graph?
  • Better diagnosis of XML errors - ? bug - diagnostic goes to command line?
• Tutor Interface
  • Only show model after a number of attempts
  • Compose models from other models to support incremental examples
  • add assessment
  • Show tags
  • Success / Fail text in Diagnose body
• Diagrams
  • SVG output with hints or links
  • Use neato instead of dot for layout?
  • Node styling
  • Show types in ER models
  • upgrade to latest graphviz - HTML labels not rendered?
• Worksheet format
  • SQL execution and diagnosis
  • Multiple choice questions
  • XQuery
  • SPARQL queries
• Normalizer
  • Inferred string lengths are too restrictive
• DDL Generation
  • Foreign key constraint for compound primary keys incorrect
  • DDL generation failing for 0-1 and 1- 1 ? check
  • 2 Many-many relationships between the same entities are not distinguished - done 2/3/09 - need to define different relationship names
  • cycles in dependencies not checked - would cause a problem!
• Other Transformations and interfaces
  • Diagram with UML notation
  • Notation for instances as well as types
  • Reverse engineer SQL DDL to XML
  • Transform to Alloy
  • Transform to Java Classes
  • Transform to PHP
  • Generate instance from model to diagram or generate test data
  • Transformation to XMLSchema
  • Create non XML DSL -see XML Sugar
  • Create drawing tool to create XML document graphically
• ER modelling difficulties to cover
  • separation of representation from basic data
    • views of the dat generated by selects to compose, select and order basic data
    • computable values - such as an area from its height and width, the count of the number of instances
    • representation variants - format of date and time
  • getting 1- many relationship round the right way
  • multiple relationships between 2 entities - such as manager , current employee , past employee
  • recurrent relationships such as employee - manager, person - friend

Created: Chris Wallace, 3 Feb 2009 - last modified 4 June 2009