diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6b2acc853d4..5f1f0b4a181 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,9 @@
 - Substantial performance improvements for parsing on large projects, especially projects with many docs definition. ([#2480](https://github.com/fishtown-analytics/dbt/issues/2480), [#2481](https://github.com/fishtown-analytics/dbt/pull/2481))
 - Expose Snowflake query id in case of an exception raised by connector ([#2201](https://github.com/fishtown-analytics/dbt/issues/2201), [#2358](https://github.com/fishtown-analytics/dbt/pull/2358))
 
+### Under the hood
+- Better support for optional database fields in adapters ([#2487](https://github.com/fishtown-analytics/dbt/issues/2487) [#2489](https://github.com/fishtown-analytics/dbt/pull/2489))
+
 Contributors:
 - [@dmateusp](https://github.com/dmateusp) ([#2475](https://github.com/fishtown-analytics/dbt/pull/2475))
 - [@ChristianKohlberg](https://github.com/ChristianKohlberg) (#2358](https://github.com/fishtown-analytics/dbt/pull/2358))
diff --git a/core/dbt/adapters/base/impl.py b/core/dbt/adapters/base/impl.py
index 479d1dac673..6af38b5264b 100644
--- a/core/dbt/adapters/base/impl.py
+++ b/core/dbt/adapters/base/impl.py
@@ -264,7 +264,7 @@ def load_internal_manifest(self) -> Manifest:
     ###
     # Caching methods
     ###
-    def _schema_is_cached(self, database: str, schema: str) -> bool:
+    def _schema_is_cached(self, database: Optional[str], schema: str) -> bool:
         """Check if the schema is cached, and by default logs if it is not."""
 
         if dbt.flags.USE_CACHE is False:
@@ -341,12 +341,8 @@ def _relations_cache_for_schemas(self, manifest: Manifest) -> None:
         # it's possible that there were no relations in some schemas. We want
         # to insert the schemas we query into the cache's `.schemas` attribute
         # so we can check it later
-        cache_update: Set[Tuple[str, Optional[str]]] = set()
+        cache_update: Set[Tuple[Optional[str], Optional[str]]] = set()
         for relation in cache_schemas:
-            if relation.database is None:
-                raise InternalException(
-                    'Got a None database in a cached schema!'
-                )
             cache_update.add((relation.database, relation.schema))
         self.cache.update_schemas(cache_update)
 
@@ -646,7 +642,9 @@ def expand_target_column_types(
 
         self.expand_column_types(from_relation, to_relation)
 
-    def list_relations(self, database: str, schema: str) -> List[BaseRelation]:
+    def list_relations(
+        self, database: Optional[str], schema: str
+    ) -> List[BaseRelation]:
         if self._schema_is_cached(database, schema):
             return self.cache.get_relations(database, schema)
 
diff --git a/core/dbt/adapters/base/relation.py b/core/dbt/adapters/base/relation.py
index 6591c48980b..44654bfb342 100644
--- a/core/dbt/adapters/base/relation.py
+++ b/core/dbt/adapters/base/relation.py
@@ -6,7 +6,7 @@
 from collections.abc import Mapping, Hashable
 from dataclasses import dataclass, fields
 from typing import (
-    Optional, TypeVar, Generic, Any, Type, Dict, Union, List, Iterator, Tuple,
+    Optional, TypeVar, Generic, Any, Type, Dict, Union, Iterator, Tuple,
     Set
 )
 from typing_extensions import Protocol
@@ -278,16 +278,11 @@ def _render_iterator(
             yield key, path_part
 
     def render(self) -> str:
-        parts: List[str] = [
-            part for _, part in self._render_iterator() if part is not None
-        ]
-
-        if len(parts) == 0:
-            raise dbt.exceptions.RuntimeException(
-                "No path parts are included! Nothing to render."
-            )
-
-        return '.'.join(parts)
+        # if there is nothing set, this will return the empty string.
+        return '.'.join(
+            part for _, part in self._render_iterator()
+            if part is not None
+        )
 
     def quoted(self, identifier):
         return '{quote_char}{identifier}{quote_char}'.format(
diff --git a/core/dbt/adapters/cache.py b/core/dbt/adapters/cache.py
index 157684fe9c2..8bbac5cc95f 100644
--- a/core/dbt/adapters/cache.py
+++ b/core/dbt/adapters/cache.py
@@ -4,25 +4,20 @@
 import threading
 
 from dbt.logger import CACHE_LOGGER as logger
+from dbt.utils import lowercase
 import dbt.exceptions
 
 _ReferenceKey = namedtuple('_ReferenceKey', 'database schema identifier')
 
 
-def _lower(value: Optional[str]) -> Optional[str]:
-    """Postgres schemas can be None so we can't just call lower()."""
-    if value is None:
-        return None
-    return value.lower()
-
-
 def _make_key(relation) -> _ReferenceKey:
     """Make _ReferenceKeys with lowercase values for the cache so we don't have
     to keep track of quoting
     """
-    return _ReferenceKey(_lower(relation.database),
-                         _lower(relation.schema),
-                         _lower(relation.identifier))
+    # databases and schemas can both be None
+    return _ReferenceKey(lowercase(relation.database),
+                         lowercase(relation.schema),
+                         lowercase(relation.identifier))
 
 
 def dot_separated(key: _ReferenceKey) -> str:
@@ -53,15 +48,15 @@ def __str__(self) -> str:
 
     @property
     def database(self) -> Optional[str]:
-        return _lower(self.inner.database)
+        return lowercase(self.inner.database)
 
     @property
     def schema(self) -> Optional[str]:
-        return _lower(self.inner.schema)
+        return lowercase(self.inner.schema)
 
     @property
     def identifier(self) -> Optional[str]:
-        return _lower(self.inner.identifier)
+        return lowercase(self.inner.identifier)
 
     def __copy__(self):
         new = self.__class__(self.inner)
@@ -190,7 +185,7 @@ def add_schema(
         :param database: The database name to add.
         :param schema: The schema name to add.
         """
-        self.schemas.add((_lower(database), _lower(schema)))
+        self.schemas.add((lowercase(database), lowercase(schema)))
 
     def drop_schema(
         self, database: Optional[str], schema: Optional[str],
@@ -199,7 +194,7 @@ def drop_schema(
 
         Then remove all its contents (and their dependents, etc) as well.
         """
-        key = (_lower(database), _lower(schema))
+        key = (lowercase(database), lowercase(schema))
         if key not in self.schemas:
             return
 
@@ -217,7 +212,7 @@ def update_schemas(self, schemas: Iterable[Tuple[Optional[str], str]]):
 
         :param schemas: An iterable of the schema names to add.
         """
-        self.schemas.update((_lower(d), s.lower()) for (d, s) in schemas)
+        self.schemas.update((lowercase(d), s.lower()) for (d, s) in schemas)
 
     def __contains__(self, schema_id: Tuple[Optional[str], str]):
         """A schema is 'in' the relations cache if it is in the set of cached
@@ -226,7 +221,7 @@ def __contains__(self, schema_id: Tuple[Optional[str], str]):
         :param schema_id: The db name and schema name to look up.
         """
         db, schema = schema_id
-        return (_lower(db), schema.lower()) in self.schemas
+        return (lowercase(db), schema.lower()) in self.schemas
 
     def dump_graph(self):
         """Dump a key-only representation of the schema to a dictionary. Every
@@ -484,13 +479,13 @@ def get_relations(
         :return List[BaseRelation]: The list of relations with the given
             schema
         """
-        database = _lower(database)
-        schema = _lower(schema)
+        database = lowercase(database)
+        schema = lowercase(schema)
         with self.lock:
             results = [
                 r.inner for r in self.relations.values()
-                if (_lower(r.schema) == schema and
-                    _lower(r.database) == database)
+                if (lowercase(r.schema) == schema and
+                    lowercase(r.database) == database)
             ]
 
         if None in results:
@@ -509,7 +504,7 @@ def _list_relations_in_schema(
         self, database: Optional[str], schema: Optional[str]
     ) -> List[_CachedRelation]:
         """Get the relations in a schema. Callers should hold the lock."""
-        key = (_lower(database), _lower(schema))
+        key = (lowercase(database), lowercase(schema))
 
         to_remove: List[_CachedRelation] = []
         for cachekey, relation in self.relations.items():
diff --git a/core/dbt/contracts/graph/parsed.py b/core/dbt/contracts/graph/parsed.py
index 70f091ecc80..9c9955f12a2 100644
--- a/core/dbt/contracts/graph/parsed.py
+++ b/core/dbt/contracts/graph/parsed.py
@@ -83,7 +83,7 @@ def add_node(self, value: str):
 
 @dataclass
 class HasRelationMetadata(JsonSchemaMixin, Replaceable):
-    database: str
+    database: Optional[str]
     schema: str
 
 
diff --git a/core/dbt/contracts/results.py b/core/dbt/contracts/results.py
index c9f9b06c97b..e9de86ff132 100644
--- a/core/dbt/contracts/results.py
+++ b/core/dbt/contracts/results.py
@@ -10,6 +10,7 @@
     JsonOnly,
     GLOBAL_LOGGER as logger,
 )
+from dbt.utils import lowercase
 from hologram.helpers import StrEnum
 from hologram import JsonSchemaMixin
 
@@ -238,7 +239,7 @@ class FreshnessRunOutput(JsonSchemaMixin, Writable):
 
 CatalogKey = NamedTuple(
     'CatalogKey',
-    [('database', str), ('schema', str), ('name', str)]
+    [('database', Optional[str]), ('schema', str), ('name', str)]
 )
 
 
@@ -247,7 +248,7 @@ class StatsItem(JsonSchemaMixin):
     id: str
     label: str
     value: Primitive
-    description: str
+    description: Optional[str]
     include: bool
 
 
@@ -268,7 +269,7 @@ class ColumnMetadata(JsonSchemaMixin):
 @dataclass
 class TableMetadata(JsonSchemaMixin):
     type: str
-    database: str
+    database: Optional[str]
     schema: str
     name: str
     comment: Optional[str]
@@ -285,7 +286,7 @@ class CatalogTable(JsonSchemaMixin, Replaceable):
 
     def key(self) -> CatalogKey:
         return CatalogKey(
-            self.metadata.database.lower(),
+            lowercase(self.metadata.database),
             self.metadata.schema.lower(),
             self.metadata.name.lower(),
         )
diff --git a/core/dbt/include/global_project/macros/etc/get_custom_database.sql b/core/dbt/include/global_project/macros/etc/get_custom_database.sql
index adbe152cb9b..bf12e366f5c 100644
--- a/core/dbt/include/global_project/macros/etc/get_custom_database.sql
+++ b/core/dbt/include/global_project/macros/etc/get_custom_database.sql
@@ -14,6 +14,10 @@
 
 #}
 {% macro generate_database_name(custom_database_name=none, node=none) -%}
+    {% do return(adapter_macro('generate_database_name', custom_database_name, node)) %}
+{%- endmacro %}
+
+{% macro default__generate_database_name(custom_database_name=none, node=none) -%}
     {%- set default_database = target.database -%}
     {%- if custom_database_name is none -%}
 
diff --git a/core/dbt/node_runners.py b/core/dbt/node_runners.py
index ffea17c0606..e1f84836bd3 100644
--- a/core/dbt/node_runners.py
+++ b/core/dbt/node_runners.py
@@ -27,6 +27,7 @@
 import dbt.tracking
 import dbt.ui.printer
 import dbt.flags
+import dbt.utils
 
 
 INTERNAL_ERROR_STRING = """This is an error in dbt. Please try again. If \
@@ -491,8 +492,7 @@ def _build_run_result(self, node, start_time, error, status, timing_info,
                           skip=False, failed=None):
         execution_time = time.time() - start_time
         thread_id = threading.current_thread().name
-        if status is not None:
-            status = status.lower()
+        status = dbt.utils.lowercase(status)
         return PartialResult(
             node=node,
             status=status,
diff --git a/core/dbt/parser/base.py b/core/dbt/parser/base.py
index 748c85172bb..ff3fa0a0e9a 100644
--- a/core/dbt/parser/base.py
+++ b/core/dbt/parser/base.py
@@ -120,7 +120,9 @@ def __call__(
         self, parsed_node: Any, config_dict: Dict[str, Any]
     ) -> None:
         override = config_dict.get(self.component)
-        new_value = self.updater(override, parsed_node).strip()
+        new_value = self.updater(override, parsed_node)
+        if isinstance(new_value, str):
+            new_value = new_value.strip()
         setattr(parsed_node, self.component, new_value)
 
 
diff --git a/core/dbt/task/generate.py b/core/dbt/task/generate.py
index d3167d93429..e78fe84649a 100644
--- a/core/dbt/task/generate.py
+++ b/core/dbt/task/generate.py
@@ -62,9 +62,15 @@ def __init__(self, columns: List[PrimitiveDict]):
             self.add_column(col)
 
     def get_table(self, data: PrimitiveDict) -> CatalogTable:
+        database = data.get('table_database')
+        if database is None:
+            dkey: Optional[str] = None
+        else:
+            dkey = str(database)
+
         try:
             key = CatalogKey(
-                str(data['table_database']),
+                dkey,
                 str(data['table_schema']),
                 str(data['table_name']),
             )
@@ -164,8 +170,9 @@ def format_stats(stats: PrimitiveDict) -> StatsDict:
 
 
 def mapping_key(node: CompileResultNode) -> CatalogKey:
+    dkey = dbt.utils.lowercase(node.database)
     return CatalogKey(
-        node.database.lower(), node.schema.lower(), node.identifier.lower()
+        dkey, node.schema.lower(), node.identifier.lower()
     )
 
 
diff --git a/core/dbt/task/runnable.py b/core/dbt/task/runnable.py
index d75040f644c..713d0d55cd9 100644
--- a/core/dbt/task/runnable.py
+++ b/core/dbt/task/runnable.py
@@ -45,12 +45,6 @@
 RUNNING_STATE = DbtProcessState('running')
 
 
-def _lower(value: Optional[str]) -> Optional[str]:
-    if value is None:
-        return value
-    return value.lower()
-
-
 def write_manifest(config, manifest):
     if dbt.flags.WRITE_JSON:
         manifest.write(os.path.join(config.target_path, MANIFEST_FILE_NAME))
@@ -453,28 +447,32 @@ def create_schemas(self, adapter, selected_uids: Iterable[str]):
             )
             required_databases.add(db_only)
 
-        existing_schemas_lowered: Set[Tuple[str, Optional[str]]] = set()
+        existing_schemas_lowered: Set[Tuple[Optional[str], Optional[str]]]
+        existing_schemas_lowered = set()
 
-        def list_schemas(db_only: BaseRelation) -> List[Tuple[str, str]]:
-            # the database name should never be None here (or where are we
-            # listing schemas from?)
+        def list_schemas(
+            db_only: BaseRelation
+        ) -> List[Tuple[Optional[str], str]]:
+            # the database can be None on some warehouses that don't support it
+            database_quoted: Optional[str]
+            db_lowercase = dbt.utils.lowercase(db_only.database)
             if db_only.database is None:
-                raise InternalException(
-                    f'Got an invalid database-only portion of {db_only} '
-                    f'(database was None)'
-                )
-            database_name: str = db_only.database
-            database_quoted = str(db_only)
-            with adapter.connection_named(f'list_{database_name}'):
+                database_quoted = None
+                conn_name = 'list_schemas'
+            else:
+                database_quoted = str(db_only)
+                conn_name = f'list_{db_only.database}'
+
+            with adapter.connection_named(conn_name):
                 # we should never create a null schema, so just filter them out
                 return [
-                    (database_name.lower(), s.lower())
+                    (db_lowercase, s.lower())
                     for s in adapter.list_schemas(database_quoted)
                     if s is not None
                 ]
 
         def create_schema(relation: BaseRelation) -> None:
-            db = relation.database
+            db = relation.database or ''
             schema = relation.schema
             with adapter.connection_named(f'create_{db}_{schema}'):
                 adapter.create_schema(relation)
@@ -491,18 +489,15 @@ def create_schema(relation: BaseRelation) -> None:
                 existing_schemas_lowered.update(ls_future.result())
 
             for info in required_schemas:
-                if info.database is None:
-                    raise InternalException(
-                        'Got an information schema with no database!'
-                    )
                 if info.schema is None:
                     # we are not in the business of creating null schemas, so
                     # skip this
                     continue
-                db: str = info.database
+                db: Optional[str] = info.database
+                db_lower: Optional[str] = dbt.utils.lowercase(db)
                 schema: str = info.schema
 
-                db_schema = (db.lower(), schema.lower())
+                db_schema = (db_lower, schema.lower())
                 if db_schema not in existing_schemas_lowered:
                     existing_schemas_lowered.add(db_schema)
                     create_futures.append(
diff --git a/core/dbt/utils.py b/core/dbt/utils.py
index e9cf218dfe0..989b93308d5 100644
--- a/core/dbt/utils.py
+++ b/core/dbt/utils.py
@@ -490,6 +490,13 @@ def coerce_dict_str(value: Any) -> Optional[Dict[str, Any]]:
         return None
 
 
+def lowercase(value: Optional[str]) -> Optional[str]:
+    if value is None:
+        return None
+    else:
+        return value.lower()
+
+
 # some types need to make constants available to the jinja context as
 # attributes, and regular properties only work with objects. maybe this should
 # be handled by the RelationProxy?