Add placeholder_factory to Parameterizer

pypika/queries.py

@@ -1228,7 +1228,8 @@ def minus(self, other: "QueryBuilder") -> _SetOperation:
     @builder
     def set(self, field: Union[Field, str], value: Any) -> "QueryBuilder":
         field = Field(field) if not isinstance(field, Field) else field
-        self._updates.append((field, self._wrapper_cls(value)))
+        value = self.wrap_constant(value, wrapper_cls=self._wrapper_cls)
+        self._updates.append((field, value))
 
     def __add__(self, other: "QueryBuilder") -> _SetOperation:
         return self.union(other)

pypika/terms.py

@@ -7,6 +7,7 @@
 from typing import (
     TYPE_CHECKING,
     Any,
+    Callable,
     Iterable,
     Iterator,
     List,
@@ -333,7 +334,8 @@ class Parameterizer:
     be accessed via the `values` attribute.
     """
 
-    def __init__(self) -> None:
+    def __init__(self, placeholder_factory: Optional[Callable[[int], str]] = None) -> None:
+        self.placeholder_factory = placeholder_factory
         self.values = []
 
     def should_parameterize(self, value: Any) -> bool:
@@ -347,7 +349,10 @@ def should_parameterize(self, value: Any) -> bool:
 
     def create_param(self, value: Any) -> Parameter:
         self.values.append(value)
-        return Parameter(idx=len(self.values))
+        if self.placeholder_factory:
+            return Parameter(self.placeholder_factory(len(self.values)))
+        else:
+            return Parameter(idx=len(self.values))
 
 
 class Negative(Term):

tests/test_parameter.py

@@ -235,3 +235,8 @@ def test_limit_and_offest_in_mssql(self):
             'SELECT * FROM "abc" ORDER BY (SELECT 0) OFFSET ? ROWS FETCH NEXT ? ROWS ONLY', sql
         )
         self.assertEqual([5, 10], parameterizer.values)
+
+    def test_placeholder_factory(self):
+        parameterizer = Parameterizer(placeholder_factory=lambda _: "%s")
+        param = parameterizer.create_param(1)
+        self.assertEqual("%s", param.get_sql())

tests/test_updates.py

@@ -43,7 +43,7 @@ def test_update__table_schema(self):
 
     def test_update_with_none(self):
         q = Query.update("abc").set("foo", None)
-        self.assertEqual('UPDATE "abc" SET "foo"=null', str(q))
+        self.assertEqual('UPDATE "abc" SET "foo"=NULL', str(q))
 
     def test_update_from(self):
         from_table = Table("from_table")