readRDF {Rredland} | R Documentation |
read an RDF document identified by URI (or deserialize a redland Berkeley DB representation) into a librdf model object
readRDF(uri, storageType=c("internal", "bdb")[1], storageName="test", world=..GredlWorld, stoHash=NULL) restoreBDB(storageName, world=..GredlWorld, stoHash="hash-type='bdb',dir='.'")
uri |
a redlURI instance, or a string encoding a URI |
storageType |
character string, with value "internal" or "bdb" |
storageName |
basename of file to store the hashes, if storageType
is "bdb" |
world |
librdf world (redlWorld class instance) |
stoHash |
a librdf hash specification of parameters to the new storage request; non-default values for advanced users only. |
Vince Carey <stvjc@channing.harvard.edu>
# use character string URI ii = readRDF(paste("file:", system.file("RDF/gopart.rdf", package="Rredland"), sep="")) ii freeRedl(ii) # make a URI for a fragment from GO distributed with the package example(makeRedlURI) # read from it with defaults mm = readRDF(uu) mm # excerpt after transformation to data.frame as(mm, "data.frame")[1:3,] # now we will do some disk operations with BDB curd = getwd() tt = tempdir() # change dir setwd(tt) # read contents of previous URI, but use external storage hh = readRDF(uu, storageType="bdb", storageName="gopart") # see the created files; note that they are not # populated until the storage/model is freed dir() # free the model, so the BDB hashes are populated freeRedl(hh) hh # now restore the hashes and create a redlModel ff = restoreBDB("gopart") ff # cleanup unlink("gopart-so2p.db") unlink("gopart-po2s.db") unlink("gopart-sp2o.db") setwd(curd) cat(paste("to clean up completely, execute unlink(\"", tt,"\", recursive=TRUE) in R, if it looks safe to do so.\n", sep=""))