1. Interexchance Languages XML COBRA UMLS 2. XML eXtensible Markup Language Used for data exchangeover the web Similar to HTML Uses document type definition to define data Mainly used to make spreadsheets for financial data It allows one to create new tags 3. XML Stores data with user defined tags XML data can be embedded with HTML code and then used to display within a browser Its flexibility and robustness makes it a excellent choice to share data BLAST, FASTA produce XML format results NCBI, EMBL, DDBJ all use XML format PIR database can be downloaded in XML Also the Gene Ontology data 4. XML Example version=1.0?> 39655100123456789 123456799 123456999 123459999 5. 1st line XML Declaration declares version 2nd line first element of the root of document an object resulting from Entrex search Next 4 lines child elements IdList, Count, RetMax, RetStart IdList has a date attribute and multiple Id sublements 6. NOTE All tags are case sensitive All elements must have a matching closing tag All elements must be correctly nested All attribute values must be quoted (abc) 7. Output EsearchResult Count RetMax RetStart IdList ID ID ID ID 123456789 123456799 123456999 123459999