Keyphrases
- xml schema
- context free grammars
- xml documents
- integrity constraints
- regular expressions
- xml data
- object oriented
- data exchange
- relational databases
- semi structured documents
- conceptual model
- metadata
- grammatical inference
- markup language
- relational schema
- building blocks
- structured data
- natural language
- database
- semi structured
- information retrieval
- conceptual schema
- context free