cx_Oracle modernize

Full "RETURNING" support is implemented for the cx_Oracle dialect, meaning
multiple RETURNING rows are now recived for DML statements that produce
more than one row for RETURNING.

cx_Oracle 7 is now the minimum version for cx_Oracle.

Getting Oracle to do multirow returning took about 5 minutes.  however,
getting Oracle's RETURNING system to integrate with ORM-enabled
insert, update, delete, is a big deal because that architecture wasn't
really working very robustly, including some recent changes in 1.4
for FromStatement were done in a hurry, so this patch also cleans up
the FromStatement situation and begins to establish it more concretely
as the base for all ReturnsRows / TextClause ORM scenarios.

Fixes: #6245
Change-Id: I2b4e6007affa51ce311d2d5baa3917f356ab961f

1 files changed, 23 insertions, 0 deletions

diff --git a/lib/sqlalchemy/sql/_typing.py b/lib/sqlalchemy/sql/_typing.py
index 0a72a93c5..bc1e0672c 100644
--- a/lib/sqlalchemy/sql/_typing.py
+++ b/lib/sqlalchemy/sql/_typing.py
@@ -14,6 +14,11 @@ from ..util.typing import Literal
 from ..util.typing import Protocol
 
 if TYPE_CHECKING:
+    from .compiler import Compiled
+    from .compiler import DDLCompiler
+    from .compiler import SQLCompiler
+    from .dml import UpdateBase
+    from .dml import ValuesBase
     from .elements import ClauseElement
     from .elements import ColumnClause
     from .elements import ColumnElement
@@ -38,6 +43,7 @@ if TYPE_CHECKING:
     from .type_api import TypeEngine
     from ..util.typing import TypeGuard
 
+
 _T = TypeVar("_T", bound=Any)
 
 
@@ -153,6 +159,12 @@ _TypeEngineArgument = Union[Type["TypeEngine[_T]"], "TypeEngine[_T]"]
 
 if TYPE_CHECKING:
 
+    def is_sql_compiler(c: Compiled) -> TypeGuard[SQLCompiler]:
+        ...
+
+    def is_ddl_compiler(c: Compiled) -> TypeGuard[DDLCompiler]:
+        ...
+
     def is_named_from_clause(t: FromClauseRole) -> TypeGuard[NamedFromClause]:
         ...
 
@@ -183,7 +195,13 @@ if TYPE_CHECKING:
     def is_subquery(t: FromClause) -> TypeGuard[Subquery]:
         ...
 
+    def is_dml(c: ClauseElement) -> TypeGuard[UpdateBase]:
+        ...
+
 else:
+
+    is_sql_compiler = operator.attrgetter("is_sql")
+    is_ddl_compiler = operator.attrgetter("is_ddl")
     is_named_from_clause = operator.attrgetter("named_with_column")
     is_column_element = operator.attrgetter("_is_column_element")
     is_text_clause = operator.attrgetter("_is_text_clause")
@@ -194,6 +212,7 @@ else:
     is_select_statement = operator.attrgetter("_is_select_statement")
     is_table = operator.attrgetter("_is_table")
     is_subquery = operator.attrgetter("_is_subquery")
+    is_dml = operator.attrgetter("is_dml")
 
 
 def has_schema_attr(t: FromClauseRole) -> TypeGuard[TableClause]:
@@ -206,3 +225,7 @@ def is_quoted_name(s: str) -> TypeGuard[quoted_name]:
 
 def is_has_clause_element(s: object) -> TypeGuard[_HasClauseElement]:
     return hasattr(s, "__clause_element__")
+
+
+def is_insert_update(c: ClauseElement) -> TypeGuard[ValuesBase]:
+    return c.is_dml and (c.is_insert or c.is_update)  # type: ignore