Re: EPICS database Feature request

["Shen, Guobao" <shengb@bnl.gov>]

Hi Emmanuel,
Not sure whether I fully understand your question, but for an exiting record,
all default fields are there no matter you use it or not.
The difference is just what the exact value it has.

For you first example: the FLNK is CONSTANT 0, and DRVH is 40
you next example FLNK is "AnotherAO", and DRVH is 0.

Therefore, you are always able to change any existing field by for example using dbpf from iocsh

epics> dbpf anotherAO.VAL 10
Record 'anotherAO.VAL' not found
epics> dbpf myAO.VAL 10
DBR_DOUBLE:         10
epics>

But again, I might miss something.

Guobao

On 6/6/14, 11:22 AM, Emmanuel Mayssat wrote:

Hello all,

A feature I use a lot with my db  file is overwriting a record, ie:

record(ao, "myAO") {

   field(VAL, "20")

   field(DRVH, "40")

}

and later in the same or another db file

record(ao, "myAO") {

   field(VAL, "21")

   field(FLNK, "AnotherAO")

}

The above is equivalent to  1 single entry with

record(ao, "mAO") {

  field(VAL, "21")

  field(DRVH, "40")

  field(FLNK, "AnotherAO")

}

Now the issue is that to overwrite the field of a record, you need to know its type (i.e. ao) as you need to repeat the record line.

Is it possible to have a database entry (maybe like the alias entry) where you could just say:

changefield("myAO", VAL, 21)

which doesn't create the record if it doesn't exist, but which perform the equivalent to 

record(ao, "myAO") {

  field(VAL, "21")

}

if it does.

Maybe a similar command already exist.

If so let me know,

--

Emmanuel