- Added :class:`.mysql.JSON` for MySQL 5.7. The JSON type provides

persistence of JSON values in MySQL as well as basic operator support
of "getitem" and "getpath", making use of the ``JSON_EXTRACT``
function in order to refer to individual paths in a JSON structure.
fixes #3547
- Added a new type to core :class:`.types.JSON`.  This is the
base of the PostgreSQL :class:`.postgresql.JSON` type as well as that
of the new :class:`.mysql.JSON` type, so that a PG/MySQL-agnostic
JSON column may be used.  The type features basic index and path
searching support.
fixes #3619
- reorganization of migration docs etc. to try to refer both to
the fixes to JSON that helps Postgresql while at the same time
indicating these are new features of the new base JSON type.
- a rework of the Array/Indexable system some more, moving things
that are specific to Array out of Indexable.
- new operators for JSON indexing added to core so that these can
be compiled by the PG and MySQL dialects individually
- rename sqltypes.Array to sqltypes.ARRAY - as there is no generic
Array implementation, this is an uppercase type for now, consistent
with the new sqltypes.JSON type that is also not a generic implementation.
There may need to be some convention change to handle the case of
datatypes that aren't generic, rely upon DB-native implementations,
but aren't necessarily all named the same thing.

1 files changed, 12 insertions, 3 deletions

diff --git a/lib/sqlalchemy/sql/operators.py b/lib/sqlalchemy/sql/operators.py
index da3576466..f4f90b664 100644
--- a/lib/sqlalchemy/sql/operators.py
+++ b/lib/sqlalchemy/sql/operators.py
@@ -12,7 +12,6 @@
 
 from .. import util
 
-
 from operator import (
     and_, or_, inv, add, mul, sub, mod, truediv, lt, le, ne, gt, ge, eq, neg,
     getitem, lshift, rshift
@@ -720,7 +719,6 @@ def istrue(a):
 def isfalse(a):
     raise NotImplementedError()
 
-
 def is_(a, b):
     return a.is_(b)
 
@@ -837,6 +835,14 @@ def nullslast_op(a):
     return a.nullslast()
 
 
+def json_getitem_op(a, b):
+    raise NotImplementedError()
+
+
+def json_path_getitem_op(a, b):
+    raise NotImplementedError()
+
+
 _commutative = set([eq, ne, add, mul])
 
 _comparison = set([eq, ne, lt, gt, ge, le, between_op, like_op])
@@ -879,7 +885,8 @@ def mirror(op):
 
 _associative = _commutative.union([concat_op, and_, or_])
 
-_natural_self_precedent = _associative.union([getitem])
+_natural_self_precedent = _associative.union([
+    getitem, json_getitem_op, json_path_getitem_op])
 """Operators where if we have (a op b) op c, we don't want to
 parenthesize (a op b).
 
@@ -894,6 +901,8 @@ _PRECEDENCE = {
     from_: 15,
     any_op: 15,
     all_op: 15,
+    json_getitem_op: 15,
+    json_path_getitem_op: 15,
     getitem: 15,
     mul: 8,
     truediv: 8,