Data Management
Detailed Information About the JGOFS Distributed Database Management System (DDMS)
Application Program Interface
From a C programs, you can call the folowing functions to obtain
information from the data system:
- maxlev = jdbopen_(&unit,obj,names,&namesize,&num)
- Opens a data object. The variable char obj[1024] is a
long string containing the object name, including parameters if
desired for selections, etc. The array of char
names[][namesize] contains num names for the variables
to be returned (if num > 0) or space for |num|
names if num< 0. In the latter case, the number of
variables found is also returned in num. The result of the
call is the maximum heirachical level of the dataset. Negative values
are error returns.
- lev = jdblevel_(&unit,&varnum)
- Return the level in the hierarchy (0=outermost, 1=next,...) of the
variable number varnum.
- lev = jdbread_(&unit,values)
- Read the next realization of the data from the object. The
subroutine fills in num values in the array of
floats.
- lev = jdbreada_(&unit,values,&valuesize)
- Same as above, but the values are read into strings
- ok = jdbcomments_(&unit,outcom)
- Return the next comment in the string outcom. The
returned value is 0 if there are no more comments.
- ok = jdbattributes_(&unit,&id,outcom)
- Return the next attribute of variable number id in the
string outcom. The returned value is 0 if there are no more
attributes.
- jdbclose_(&unit)
- Close the object.
In Fortran, the calls are
maxlev = jdbopen(unit,obj,names,namesize,num)
lev = jdblevel(unit,varnum)
lev = jdbread(unit,values)
lev = jdbreada(unit,values,valuesize)
ok = jdbcomments(unit,outcom)
call jdbclose(unit)
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