ds.testObjExists {dsBaseClient}R Documentation

Checking that a correct version of a data object exists on a data source server


This function checks that a specified data object exists or has been correctly created on a specified set of data servers (may be only one data server).


ds.testObjExists(test.obj.name = NULL, datasources = NULL)



a character string specifying the name of the object to search for e.g. "TID.f"


specifies the particular opal object(s) to use, if it is not specified the default set of opals will be used. The default opals are always called default.opals. This parameter is set without inverted commas: e.g. datasources=opals.em or datasources=default.opals If you wish to specify the second opal server in a set of three, the parameter is specified: e.g. datasources=opals.em[2]. If you wish to specify the first and third opal servers in a set specify: e.g. datasources=opals.em[2,3]


The data object to search for is defined as a character string to the argument test.obj.name. The set of data servers to search on is provided as the argument datasources. Close copies of the code in this function are embedded into other functions that create an object and you then wish to test whether it has successfully been created e.g. ds.make, ds.asFactor


If the specified data object exists and is of a valid class (i.e. is not null) in every one of the datasources specified by the datasources argument, the function returns a list with a single element $return.message which is of the form: "A valid copy of data object <TID.f> exists in all specified data sources". If the specified object is non-existant in at least one of the specified data sources or it exists but is of class "null", the $return message is of the form: "Error: A valid data object TID.h does NOT exist in ALL specified data sources" "It is either ABSENT and/or has no valid content/class, for details see return.info above". The list return.info then includes a list of each data source with an indication of whether the data object being tested exists at all e.g. for study 3 return of the list object $return.info$study3$test.obj.exists = FALSE implies that the tested object does not exist even as a name in study 3 while return of the list object $return.info$study3$test.obj.class = "ABSENT" implies that even if the tested object exists as a name in study 3 it does not have a valid class (so contains no data etc)


Burton PR

[Package dsBaseClient version 5.0.0 ]