CCSD3ZF0000100000001NJPL3IF0PDS200000001 = SFDU_LABEL RECORD_TYPE = STREAM PRODUCT_CREATION_TIME = 1992-05-13 OBJECT = TEXT NOTE = "Description of Planetary Science Data Dictionary tables." END_OBJECT = TEXT END THE PLANETARY SCIENCE DATA DICTIONARY DELIMITED ASCII FORMAT This text accompanies a number of delimited-ASCII tables that form the bulk of the Planetary Science Data Dictionary. These tables are designed to be bulk-loaded into any relational database management system. The table descriptions include logical links that should be created between tables, so that key information may remain consistent. The Planetary Science Data Dictionary is a single, logical database of information, however, we have split it into two sections. The first part, the Data Element Database, contains descriptions of individual data elements (or attributes, or descriptors) that are used to describe science data products. The key to almost every table in this database is the Column name (or data element name). The second part of the Planetary Science Data Dictionary identifies and describes what we call Data Objects. Objects can be data structures like image, table, or spectrum; catalog structures like a database table; or physical entities like spacecraft instruments. The objects described in this set of tables contain lists of attributes that are required for describing the object, and others that are optional descriptors. This helps us standardize the way things are described in our catalog, and it helps us validate the structure of data descriptions. ---- THE DATA ELEMENT DATABASE COLTN (column name/terse name) contains status information for each data element. This is the master table of the data element database. It is linked to each of the other tables in a one-to- many relationship. Column name Terse name General data type Unit Standard value type Standard value key Maximum Minimum Maximum length Minimum length Date last changed ------ CDESC (column description) is linked to COLTN by Column name, and lists the descriptions for each data element name split up into numbered, 60-character lines. Column name Sequence number Description ------ STDVALS (Standard values) is linked to COLTN by Column name, and lists each standard value associated with its data element name. We do not use the output flag yet -- it is designed to help in the creation of a printed data dictionary document. Column name Standard value Output flag ------ INDKEY (Index key) is linked to COLTN by Column name. It assigns each data element one or more general classifications. This is meant to help a user obtain collections of data elements that pertain to particular types of data products. Column name Index classification ----- UNIT is linked to COLTN by Unit. It is a list of units of measurement. Symbol Unit name Measured quantity ----- CALIAS (Column alias) shows each alias associated with a data element, and the objects in which aliasing is allowed. Data element name Alias Object ----- ATTROBJ (Attribute/object) shows in which object each data element appears, and whether or not it is a required descriptor Column name Required flag Object name THE OBJECT DATABASE OBJECTS contains basic information about each data object. This is the master table of the Objects database. It is linked to each of the other tables in a one-to-many relationship. Object name Object terse name Status type Source name Definition date Object type ----- OBJDESC (Object description) is linked to OBJECTS by Object name, and lists the descriptions for each object name split up into numbered, 60-character lines. Object name Sequence number Description ----- OBJHIER (Object hierarchy) is linked to OBJECTS by Object name, and tracks all hierarchical relationships between objects. Some objects are required to describe other objects -- the Column Object is required to describe a Table, for example. Other objects are optional. Object name Required flag Subobject name ----- OBJATTR (Object/Attribute) is linked to OBJECTS by Object name. It is a mirror image of the ATTROBJ table in the data element database. It shows the data elements that appear in each object, and indicates whether or not the data element is a required descriptor. (This table duplicates the other because we were unable to indicate many-to-many relationships on our PC- based relational database system. A more robust system would be able to use only one of these tables.) Object name Required flag Column name ----- OBJALIAS (Object alias) is linked to OBJECTS by Object name, and indicates any names that have been used previously for a particular data object Object name Alias name ----- STATNOT (Object status note) is a table that allows the system managers to include notes on the objects provenance, progress or use in the system. It is linked to OBJECTS by Object name, and lists the status notes for each object name split up into numbered, 60-character lines. Object name Sequence number Status note