dabo Commit
Revision 4731
Date: 2008-11-28 17:52:11 -0800 (Fri, 28 Nov 2008)
Author: Ed
Trac: http://svn.dabodev.com/trac/dabo/changeset/4731
Changed:
U trunk/dabo/db/dDataSet.py
Log:
Improved the handling of empty datasets. No longer will exceptions be raised;
instead, None will be returned on an execute against an empty dataset, and the
original will be returned on a filter on an empty dataset.
Diff:
Modified: trunk/dabo/db/dDataSet.py
===================================================================
--- trunk/dabo/db/dDataSet.py 2008-11-28 16:26:43 UTC (rev 4730)
+++ trunk/dabo/db/dDataSet.py 2008-11-29 01:52:11 UTC (rev 4731)
@@ -143,6 +143,9 @@
endswith: LIKE '%<expr>'
contains: LIKE '%<expr>%'
"""
+ if not self:
+ # No rows, so nothing to filter
+ return self
opDict = {"eq": " = ?",
"equals": " = ?",
"gt": " > ?",
@@ -256,7 +259,7 @@
alias = "dataset"
if len(ds) == 0:
# Can't create and populate a table without a structure
- dabo.errorLog.write(_("Cannot populate without data for
alias %s")
+ dabo.errorLog.write(_("Cannot populate without data for
alias '%s'")
% alias)
return None
if ds._populated:
@@ -323,6 +326,9 @@
# Create the table for this dDataSet
self._populate(self, "dataset")
+ if not self._populated:
+ # No data in the dataset
+ return None
# pt = time.clock()
# print "POPULATED", pt-st
@@ -657,13 +663,29 @@
if __name__ == "__main__":
- data = [{"name" : "Ed Leafe", "age" : 48, "coder" : True, "color":
"brown"},
- {"name" : "Mike Leafe", "age" : 19, "coder" :
False, "color": "purple"},
- {"name" : "Dan Leafe", "age" : 14, "coder" :
False, "color": "green"},
- {"name" : "Paul McNett", "age" : 38, "coder" :
True, "color": "red"}]
+ data = [{"name" : "Ed Leafe", "age" : 51, "coder" : True, "color":
"brown"},
+ {"name" : "Mike Leafe", "age" : 21, "coder" :
False, "color": "purple"},
+ {"name" : "Dan Leafe", "age" : 17, "coder" :
False, "color": "green"},
+ {"name" : "Paul McNett", "age" : 39, "coder" :
True, "color": "red"}]
ds = dDataSet(data)
newDS = ds.execute("select name, age from dataset where age > 30")
print "Over 30:"
for rec in newDS:
print "\tName: %(name)s, Age: %(age)s" % rec
+
+ emptyDS = ds.filter("age", 99, "gt")
+ if not emptyDS:
+ print "No one is over 99 years old"
+ else:
+ print "There are %s people over 99 years old" % len(emptyDS)
+ filt = emptyDS.filter("foo", "bar")
+
+ leafeDS = ds.filter("name", "Leafe", "endswith")
+ if not leafeDS:
+ print "No one is is named 'Leafe'"
+ else:
+ print "There are %s people named 'Leafe'" % len(leafeDS)
+ orig = leafeDS.removeFilters()
+ print "The original dataset has %s records." % len(orig)
+
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