diff --git a/dbt/adapters/mariadb/connections.py b/dbt/adapters/mariadb/connections.py
index 879b260..c67a56a 100644
--- a/dbt/adapters/mariadb/connections.py
+++ b/dbt/adapters/mariadb/connections.py
@@ -18,7 +18,7 @@
 class MariaDBCredentials(Credentials):
     server: str = ""
     port: Optional[int] = None
-    database: str = ""
+    database: Optional[str] = None
     schema: str = ""
     username: Optional[str] = None
     password: Optional[str] = None
diff --git a/dbt/adapters/mysql/connections.py b/dbt/adapters/mysql/connections.py
index 087aa4a..8c00e6b 100644
--- a/dbt/adapters/mysql/connections.py
+++ b/dbt/adapters/mysql/connections.py
@@ -18,7 +18,7 @@
 class MySQLCredentials(Credentials):
     server: str = ""
     port: Optional[int] = None
-    database: str = ""
+    database: Optional[str] = None
     schema: str = ""
     username: Optional[str] = None
     password: Optional[str] = None
diff --git a/dbt/adapters/mysql5/connections.py b/dbt/adapters/mysql5/connections.py
index e6c6ed8..2eb7e96 100644
--- a/dbt/adapters/mysql5/connections.py
+++ b/dbt/adapters/mysql5/connections.py
@@ -18,7 +18,7 @@
 class MySQLCredentials(Credentials):
     server: str = ""
     port: Optional[int] = None
-    database: str = ""
+    database: Optional[str] = None
     schema: str = ""
     username: Optional[str] = None
     password: Optional[str] = None