feat: add database.create_tables config setting

Users can disable automatic table creation for production mode:

    dj.config.database.create_tables = False

Or via environment variable DJ_CREATE_TABLES or datajoint.json.

When False, Schema will raise an error when accessing missing tables
instead of creating them. Explicit create_tables=True in Schema()
overrides the config setting.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: dimitri-yatsenko

src/datajoint/schemas.py

@@ -72,7 +72,8 @@ class Schema:
     create_schema : bool, optional
         If False, raise error if schema doesn't exist. Default True.
     create_tables : bool, optional
-        If False, raise error when accessing missing tables. Default True.
+        If False, raise error when accessing missing tables.
+        Default from ``dj.config.database.create_tables`` (True unless configured).
     add_objects : dict, optional
         Additional objects for the declaration context.
 
@@ -93,7 +94,7 @@ def __init__(
         *,
         connection: Connection | None = None,
         create_schema: bool = True,
-        create_tables: bool = True,
+        create_tables: bool | None = None,
         add_objects: dict[str, Any] | None = None,
     ) -> None:
         """
@@ -110,15 +111,16 @@ def __init__(
         create_schema : bool, optional
             If False, raise error if schema doesn't exist. Default True.
         create_tables : bool, optional
-            If False, raise error when accessing missing tables. Default True.
+            If False, raise error when accessing missing tables.
+            Default from ``dj.config.database.create_tables`` (True unless configured).
         add_objects : dict, optional
             Additional objects for the declaration context.
         """
         self.connection = connection
         self.database = None
         self.context = context
         self.create_schema = create_schema
-        self.create_tables = create_tables
+        self.create_tables = create_tables if create_tables is not None else config.database.create_tables
         self.add_objects = add_objects
         self.declare_list = []
         if schema_name:

src/datajoint/settings.py

@@ -61,6 +61,7 @@
     "database.password": "DJ_PASS",
     "database.port": "DJ_PORT",
     "database.schema_prefix": "DJ_SCHEMA_PREFIX",
+    "database.create_tables": "DJ_CREATE_TABLES",
     "loglevel": "DJ_LOG_LEVEL",
 }
 
@@ -192,6 +193,12 @@ class DatabaseSettings(BaseSettings):
         description="Project-specific prefix for schema names. "
         "Not automatically applied; use dj.config.database.schema_prefix when creating schemas.",
     )
+    create_tables: bool = Field(
+        default=True,
+        validation_alias="DJ_CREATE_TABLES",
+        description="Default for Schema create_tables parameter. "
+        "Set to False for production mode to prevent automatic table creation.",
+    )
 
 
 class ConnectionSettings(BaseSettings):