Data Management

DDMS Overview


Basic Elements

Data Objects


User Applications

Manipulating Data


Further Info

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.
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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