Squash the OptimizerHints mixin into the base dialect and thus all dialects (even when not used)

It is currently defined and used only in MS SQL, MySQL, and Oracle. Other databases simply do not support this method. It will not damage the query if we add the SQL comment there if the database does not support it.

Author: Sergey Vasilyev

data_diff/abcs/mixins.py

@@ -120,14 +120,3 @@ class AbstractMixin_MD5(AbstractMixin):
     @abstractmethod
     def md5_as_int(self, s: str) -> str:
         "Provide SQL for computing md5 and returning an int"
-
-
-@attrs.define(frozen=False)
-class AbstractMixin_OptimizerHints(AbstractMixin):
-    @abstractmethod
-    def optimizer_hints(self, optimizer_hints: str) -> str:
-        """Creates a compatible optimizer_hints string
-
-        Parameters:
-            optimizer_hints - string of optimizer hints
-        """

data_diff/databases/base.py

@@ -74,10 +74,7 @@
     JSON,
 )
 from data_diff.abcs.mixins import Compilable
-from data_diff.abcs.mixins import (
-    AbstractMixin_NormalizeValue,
-    AbstractMixin_OptimizerHints,
-)
+from data_diff.abcs.mixins import AbstractMixin_NormalizeValue
 
 logger = logging.getLogger("database")
 cv_params = contextvars.ContextVar("params")
@@ -198,12 +195,6 @@ def apply_query(callback: Callable[[str], Any], sql_code: Union[str, ThreadLocal
         return callback(sql_code)
 
 
-@attrs.define(frozen=False)
-class Mixin_OptimizerHints(AbstractMixin_OptimizerHints):
-    def optimizer_hints(self, hints: str) -> str:
-        return f"/*+ {hints} */ "
-
-
 @attrs.define(frozen=False)
 class BaseDialect(abc.ABC):
     SUPPORTS_PRIMARY_KEY: ClassVar[bool] = False
@@ -771,6 +762,9 @@ def to_string(self, s: str) -> str:
     def set_timezone_to_utc(self) -> str:
         "Provide SQL for setting the session timezone to UTC"
 
+    def optimizer_hints(self, hints: str) -> str:
+        return f"/*+ {hints} */ "
+
 
 T = TypeVar("T", bound=BaseDialect)
 

data_diff/databases/mssql.py

@@ -5,7 +5,6 @@
 from data_diff.abcs.mixins import AbstractMixin_MD5, AbstractMixin_NormalizeValue
 from data_diff.databases.base import (
     CHECKSUM_HEXDIGITS,
-    Mixin_OptimizerHints,
     CHECKSUM_OFFSET,
     QueryError,
     ThreadedDatabase,
@@ -39,7 +38,6 @@ def import_mssql():
 @attrs.define(frozen=False)
 class Dialect(
     BaseDialect,
-    Mixin_OptimizerHints,
     AbstractMixin_MD5,
     AbstractMixin_NormalizeValue,
 ):

data_diff/databases/mysql.py

@@ -20,7 +20,6 @@
     AbstractMixin_NormalizeValue,
 )
 from data_diff.databases.base import (
-    Mixin_OptimizerHints,
     ThreadedDatabase,
     import_helper,
     ConnectError,
@@ -44,7 +43,6 @@ def import_mysql():
 @attrs.define(frozen=False)
 class Dialect(
     BaseDialect,
-    Mixin_OptimizerHints,
     AbstractMixin_MD5,
     AbstractMixin_NormalizeValue,
 ):

data_diff/databases/oracle.py

@@ -19,7 +19,6 @@
 from data_diff.abcs.mixins import AbstractMixin_MD5, AbstractMixin_NormalizeValue
 from data_diff.databases.base import (
     BaseDialect,
-    Mixin_OptimizerHints,
     ThreadedDatabase,
     import_helper,
     ConnectError,
@@ -43,7 +42,6 @@ def import_oracle():
 @attrs.define(frozen=False)
 class Dialect(
     BaseDialect,
-    Mixin_OptimizerHints,
     AbstractMixin_MD5,
     AbstractMixin_NormalizeValue,
 ):