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Andrew Johnson APS Engineering Support Division

Explain the distinction between condition-defined and user-defined constraints. Which of these constraints can the system check automatically? Explain your answer. Answer: In a generalization–specialization hierarchy, it must be possible to de- cide which entities are members of which lower level entity sets. In a condition- defined design constraint, membership in the lower level entity-sets is evalu- ated on the basis of whether or not an entity satisfies an explicit condition or predicate.User-defined lower-level entity sets are not constrained by a member- ship condition; rather, entities are assigned to a given entity set by the database user. Condition-defined constraints alone can be automatically handled by the sys- tem. Whenever any tuple is. | .4 Argonne NATIONAL LABORATORY . fora brighter future EPICS Database Practice iff U.S. Department of Energy UChicago ArgonneLLC Office of Science U.S. DEPiRTMEHT OFENERŨY A U.S. Department of Energy laboratory managed by UChicago Argonne LLC Andrew Johnson APS Engineering Support Division January 2007 USPAS EPICS Course EPICS record types Where do record types come from - EPICS Base base src rec General purpose record types No record-type specific operator displays or databases Documentation in EPICS Record Reference Manual - EPICS collaboration General purpose and application-specific record types Some are supported for use by collaborators some are NOT Some come with record-type specific displays databases - Custom record types can be written by an EPICS developer and added to an EPICS application. Not in the scope of this lecture Argonne NATIONAL LABORATORY The Record Reference Manual Where is it - EPICS Home Base R3.13 Reference Documents html What is in it - Database Concepts good review - Fields common to all records covered earlier - Fields common to many records covered earlier - Record Types - provides a description of the record processing routines for most of the record types in base. When would I use it - Skim through before writing any databases - Read through before writing any records - Otherwise use as reference Argonne NATIONAL .