Simplify code by assumming both SQLA and Peewee

CHANGELOG.rst

@@ -19,6 +19,7 @@ This document records the main changes to the ``sdssdb`` code.
 * Add `.PeeweeDatabaseConnection.get_model` to retrieve the model for a given table.
 * :bug:`28` Temporarily remove SQLAlchemy implementation of ``sds5db`` since it's not maintained. We may reintroduce it later once the schema is stable.
 * Use ``host=localhost`` when a profile is being used on its own domain.
+* :support:`32` Assume that both SQLAlchemy and Peewee will be installed and simplify code.
 
 * :release:`0.3.2 <2020-03-10>`
 * Change ``operations-test`` profile to ``operations`` using the new machine hostname.

python/sdssdb/__init__.py

@@ -19,23 +19,5 @@
 config = get_config(NAME, user_path='~/.sdssdb/sdssdb.yml')
 
 
-try:
-    import peewee  # noqa
-    _peewee = True
-except ImportError:
-    _peewee = False
-
-try:
-    import sqlalchemy  # noqa
-    _sqla = True
-except ImportError:
-    _sqla = False
-    if _peewee is False:
-        raise ImportError('neither SQLAlchemy nor Peewee are installed. '
-                          'Install at least one of them to use sdssdb.')
-
-
-if _peewee:
-    from .connection import PeeweeDatabaseConnection  # noqa
-if _sqla:
-    from .connection import SQLADatabaseConnection  # noqa
+from .connection import PeeweeDatabaseConnection  # noqa
+from .connection import SQLADatabaseConnection  # noqa