Use of a Relational Database at Leda

1. Use of a Relational Database at Leda Bob Dalesio 11-27-98

2. Previous Approach • Wiring diagrams in Access (RDB) • Database in Capfast

3. Capfast Graphical View of data Hierarchical creation/viewing Drawing to make relationships RDB Easy tabular report generation Arbitrary Query Capability Table entry to configure Capfast Vs. RDB

4. Capfast Discussion • Capfast is a very easy tool to use to define hierarchical systems - subsystem, devices, components. • Capfast uses lines to depict relationships between these elements (these show record processing and data flow very intuitively) • Many instances of the components can be created with only one copy of the template - which can be modified at any time - changing all instances • Fields like DTYP, LINR, EGUF, EGUL, ZNAM, ONAM are all in property sheets that must be opened to modify them • Changes to these fields require selecting each property to modify • Arbitrary reports are not possible - unless the ASCII report is fed into a relational database (we have a prototype tool operational to do this)

5. RDB Discussion • An RDB provides very versatile report generation capability • Data entry is particularly easy - particularly for entering the same value into many records at the same time • The ability to order the report based on any field makes the verification of hardware addresses and the checking of name spelling particularly simple • It is very difficult to see complex EPICS record relationships by following the text entries in an RDB • Data and processing links would be more difficult to enter as names would need to be spelled properly (where Capfast only requires a wire)

6. LEDA Vacuum System Approach • Use Capfast to create the hierarchical description of the database - subsystem, device, component, signals • Use Capfast to configure the process flow and data flow - making all SCAN, FLNK, soft INP/OUT, NPP/PP, CALC, and HIGH for BO visible on the schematic. • From the Capfast produced database - create an Access database • In Access - enter configuration fields: hw INP/OUT, LINR, DTYP, EGUF, EUGL, ZNAM, ONAM etc…. • Load the database from Capfast then the database from Access - EPICS will create records if there is no existing record - or overwrite any fields in the last loaded database

7. Results • Capfast database was defined by the project engineer • RDB parameters were entered by a technician • Reports generated for signal checkout from Access expedited the process • Changes required to classes of channels for labels, hardware type and engineering units could be done to 10’s or hundreds of records in seconds • Loading two databases slows the reboot time by about 10 seconds. • Having the source in two places requires more coordination. • Deleting or changing the names of existing records was the most difficult operation - it required locating and deleting the records in Access • The inconvenience for deleting records was more than compensated for by the ease of channel check out and ability to reconfigure many channels at once. The schematics are still the easiest way to understand a database.