[CalendarServer-changes] [8123] CalendarServer/trunk/twext/enterprise/dal

[source_changes at macosforge.org]

Revision: 8123
          http://trac.macosforge.org/projects/calendarserver/changeset/8123
Author:   glyph at apple.com
Date:     2011-09-26 22:54:33 -0700 (Mon, 26 Sep 2011)
Log Message:
-----------
empty string / NULL comparisons in Oracle

Modified Paths:
--------------
    CalendarServer/trunk/twext/enterprise/dal/syntax.py
    CalendarServer/trunk/twext/enterprise/dal/test/test_sqlsyntax.py

Modified: CalendarServer/trunk/twext/enterprise/dal/syntax.py
===================================================================
--- CalendarServer/trunk/twext/enterprise/dal/syntax.py	2011-09-27 02:49:59 UTC (rev 8122)
+++ CalendarServer/trunk/twext/enterprise/dal/syntax.py	2011-09-27 05:54:33 UTC (rev 8123)
@@ -658,16 +658,22 @@
 
 
     def subSQL(self, metadata, allTables):
+        if ( metadata.dialect == ORACLE_DIALECT
+             and isinstance(self.b, Constant) and self.b.value == ''
+             and self.op in ('=', '!=') ):
+            return NullComparison(self.a, self.op).subSQL(metadata, allTables)
         stmt = SQLFragment()
         result = self._subexpression(self.a, metadata, allTables)
-        if isinstance(self.a, CompoundComparison) and self.a.op == 'or' and self.op == 'and':
+        if (isinstance(self.a, CompoundComparison)
+            and self.a.op == 'or' and self.op == 'and'):
             result = _inParens(result)
         stmt.append(result)
 
         stmt.text += ' %s ' % (self.op,)
 
         result = self._subexpression(self.b, metadata, allTables)
-        if isinstance(self.b, CompoundComparison) and self.b.op == 'or' and self.op == 'and':
+        if (isinstance(self.b, CompoundComparison)
+            and self.b.op == 'or' and self.op == 'and'):
             result = _inParens(result)
         stmt.append(result)
         return stmt

Modified: CalendarServer/trunk/twext/enterprise/dal/test/test_sqlsyntax.py
===================================================================
--- CalendarServer/trunk/twext/enterprise/dal/test/test_sqlsyntax.py	2011-09-27 02:49:59 UTC (rev 8122)
+++ CalendarServer/trunk/twext/enterprise/dal/test/test_sqlsyntax.py	2011-09-27 05:54:33 UTC (rev 8123)
@@ -164,6 +164,36 @@
                               "select * from FOO where BAR is not null", []))
 
 
+    def test_compareWithEmptyStringOracleSpecialCase(self):
+        """
+        Oracle considers the empty string to be a NULL value, so comparisons
+        with the empty string should be 'is NULL' comparisons.
+        """
+        # Sanity check: let's make sure that the non-oracle case looks normal.
+        self.assertEquals(Select(
+            From=self.schema.FOO,
+            Where=self.schema.FOO.BAR == '').toSQL(),
+            SQLFragment(
+                "select * from FOO where BAR = ?", [""]))
+        self.assertEquals(Select(
+            From=self.schema.FOO,
+            Where=self.schema.FOO.BAR != '').toSQL(),
+            SQLFragment(
+                "select * from FOO where BAR != ?", [""]))
+        self.assertEquals(Select(
+            From=self.schema.FOO,
+            Where=self.schema.FOO.BAR == ''
+        ).toSQL(NumericPlaceholder(ORACLE_DIALECT)),
+            SQLFragment(
+                "select * from FOO where BAR is null", []))
+        self.assertEquals(Select(
+            From=self.schema.FOO,
+            Where=self.schema.FOO.BAR != ''
+        ).toSQL(NumericPlaceholder(ORACLE_DIALECT)),
+            SQLFragment(
+                "select * from FOO where BAR is not null", []))
+
+
     def test_compoundWhere(self):
         """
         L{Select.And} and L{Select.Or} will return compound columns.
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