07/03/03 48821 CTB Converted to XML format This relation specifies the source of selected keywords. The source may be specified in three ways, from the PDB (Project Database), from the PMDB (Proposal management Database), or as a difference calculation. In the first case (PDB) the source of the keyword will be the name of a mnemonic as specified in the EUDL.DAT file of the PDB. The OPUS software will look up the location of that mnemonic in the yurintab relation. If it is desired to convert the value of the mnemonic to a string (discrete conversion) or to engineering units (linear or polynomial conversion), then the second field (subsource) specifies the 8 character mnemonic of a conversion. See the description of conv_discrete, conv_linear, and conv_polynomial. In the second case (PMDB) the source field is the name of a database relation in the PMDB. The subsource specifies the name of the field in that relation. Only relations which can be joined with the relation qolink on the basis of program_id, obset_id and ob_number can be used. There is a special case of deep relations like qesiparm. In this case there is only a field for si_par_name and si_par_value, both of which are string fields. To obtain a value from such a deep relation, specify the name of the parameter in a form (usually uppercase) that will match the value in the database. Finally, for keywords which are simply differences between two already dredged keywords, only the names of the subtrahend and minuend mnemonics are required for the source and subsource fields. C3 short instrument name NIC STI C8 Name of the keyword C8 which kind of source applies PDB PMDB DELTA C30 source name: mnemonic, relation, subtrahend C30 specify: conversion mnemonic, fieldname or parameter name, minuend mnemonic KEYWORD_SOURCE Source of the keyword values OPUS unique clustered