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Database tools
An SQL layer around CDF
Overview
• Current SPENVIS database
• Limitations
• SQL wrapped CDF
• Advantages
• Demonstration
Current SPENVIS database
• Data is stored in Common Data Format file (CDF)
• Programming language (IDL) supports CDF natively
• All SPENVIS tools are “file-aware”• open, read, close• combine multiple files
Limitations of custom database
• Few advanced features/interfaces•New features/interfaces require large
programming overhead
• Difficult to extend SPENVIS functionality•New functions may require database
modification
• Few languages support CDF natively• Awkward intermediate objects
SQL wrapped CDF
• Off-the-shelf DBMS (PostgreSQL)
• DBMS backend extension (C)•Open, read, close CDF file
• Metadata tables• File, variable, dimension
• Triggers & functions• Automatic population of metadata tables• Epoch arithmetic
Advantages
• Backward compatible•Old tools can still use CDF file access•New tools can use DBMS interface
• New tools are no longer “file-aware”• open, close, multiple files: handled by DBMS
• New data not (necessarily) in files• Improves performance
• Many languages support SQL natively•Choice of best fit technology
Demonstration
HTTP+PHP
DBMS
CDF
Now
HTTP+
PHP
Possible
DBMSCDF
CDFDBMSHTTP+
PHP
Future
Screenshots
Screenshots
Screenshots
Screenshots
Screenshots