Database tools An SQL layer around CDF. Overview Current SPENVIS database Limitations SQL wrapped...

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