Question

Can the python interface be used to directly access and iterate through an intersystems cache global, or does python simply expose the same “tables” I see when I use a linked server or ODBC Connection?

Answer 1

If you want to directly access globals you can create a stored procedure that will do so. You should consider the security implications before you do this – it will expose all data in the global to anyone with ODBC access.

Here is an example of a stored procedure that returns the values of up to 9 global subscripts, plus the value at that node. You can modify it pretty easily if you need to.

Query OneGlobal(GlobalName As %String) As %Query(ROWSPEC = "NodeValue:%String,Sub1:%String,Sub2:%String,Sub3:%String,Sub4:%String,Sub5:%String,Sub6:%String,Sub7:%String,Sub8:%String,Sub9:%String") [SqlProc]
{
}

ClassMethod OneGlobalExecute(ByRef qHandle As %Binary, GlobalName As %String) As %Status
{
    S qHandle="^"_GlobalName
    Quit $$$OK
}

ClassMethod OneGlobalClose(ByRef qHandle As %Binary) As %Status [ PlaceAfter = OneGlobalExecute ]
{
    Quit $$$OK
}

ClassMethod OneGlobalFetch(ByRef qHandle As %Binary, ByRef Row As %List, ByRef AtEnd As %Integer = 0) As %Status [ PlaceAfter = OneGlobalExecute ]
{

    S Q=qHandle  
    S Q=$Q(@Q)  b  
    I Q="" S Row="",AtEnd=1 Q $$$OK
    S Depth=$QL(Q)
    S $LI(Row,1)=$G(@Q)
    F I=1:1:Depth S $LI(Row,I+1)=$QS(Q,I)
    F I=Depth+1:1:9 S $LI(Row,I+1)=""
    S AtEnd=0
    S qHandle=Q
    Quit $$$OK
}

To access this from python you might use (with pyodbc):

import pyodbc
import win32com.client
import urllib2

class CacheOdbcClient:

    connectionString="DSN=MYCACHEDSN"

    def __init__(self):
        pass

    def getGlobalAsOverlyLargeList(self):
        connection=pyodbc.connect(self.connectionString)
        cursor=connection.cursor()
        cursor.execute("call MyPackageName.MyClassName_OneGlobal ?","MYGLOBAL")
        list=[]
        for row in cursor :
            list.append((row.NodeValue,row.Sub1,row.Sub2,row.Sub3,row.Sub4,row.Sub5,row.Sub6,row.Sub7,row.Sub8,row.Sub9))
        return list