diff --git a/services/ans/include/event_report.h b/services/ans/include/event_report.h
index cae2668f239adac8a203e4b54863f50585220d59..e46bbdca976e6046ef3205ded72407cb6aed65d5 100644
--- a/services/ans/include/event_report.h
+++ b/services/ans/include/event_report.h
@@ -26,20 +26,20 @@ namespace OHOS {
 namespace Notification {
 namespace {
 // event name
-const std::string SUBSCRIBE_ERROR = "SUBSCRIBE_ERROR";
-const std::string ENABLE_NOTIFICATION_ERROR = "ENABLE_NOTIFICATION_ERROR";
-const std::string ENABLE_NOTIFICATION_SLOT_ERROR = "ENABLE_NOTIFICATION_SLOT_ERROR";
-const std::string PUBLISH_ERROR = "PUBLISH_ERROR";
-const std::string FLOW_CONTROL_OCCUR = "FLOW_CONTROL_OCCUR";
+constexpr char SUBSCRIBE_ERROR[] = "SUBSCRIBE_ERROR";
+constexpr char ENABLE_NOTIFICATION_ERROR[] = "ENABLE_NOTIFICATION_ERROR";
+constexpr char ENABLE_NOTIFICATION_SLOT_ERROR[] = "ENABLE_NOTIFICATION_SLOT_ERROR";
+constexpr char PUBLISH_ERROR[] = "PUBLISH_ERROR";
+constexpr char FLOW_CONTROL_OCCUR[] = "FLOW_CONTROL_OCCUR";
 
-const std::string SUBSCRIBE = "SUBSCRIBE";
-const std::string UNSUBSCRIBE = "UNSUBSCRIBE";
-const std::string ENABLE_NOTIFICATION = "ENABLE_NOTIFICATION";
-const std::string ENABLE_NOTIFICATION_SLOT = "ENABLE_NOTIFICATION_SLOT";
+constexpr char SUBSCRIBE[] = "SUBSCRIBE";
+constexpr char UNSUBSCRIBE[] = "UNSUBSCRIBE";
+constexpr char ENABLE_NOTIFICATION[] = "ENABLE_NOTIFICATION";
+constexpr char ENABLE_NOTIFICATION_SLOT[] = "ENABLE_NOTIFICATION_SLOT";
 
-const std::string PUBLISH = "PUBLISH";
-const std::string CANCEL = "CANCEL";
-const std::string REMOVE = "REMOVE";
+constexpr char PUBLISH[] = "PUBLISH";
+constexpr char CANCEL[] = "CANCEL";
+constexpr char REMOVE[] = "REMOVE";
 } // namespace
 
 struct EventInfo {
diff --git a/services/ans/include/preferences_constant.h b/services/ans/include/preferences_constant.h
index 80434070058fdcf4b78cb3f1d8996ebcbc724e4a..c99d818fddb35296b8b324b8f66b4be0c186c92c 100644
--- a/services/ans/include/preferences_constant.h
+++ b/services/ans/include/preferences_constant.h
@@ -18,195 +18,15 @@
 
 namespace OHOS {
 namespace Notification {
-/**
- * Indicates that disturbe key which do not disturbe type.
- */
-const static std::string KEY_DO_NOT_DISTURB_TYPE = "ans_doNotDisturbType";
-
-/**
- * Indicates that disturbe key which do not disturbe begin date.
- */
-const static std::string KEY_DO_NOT_DISTURB_BEGIN_DATE = "ans_doNotDisturbBeginDate";
-
-/**
- * Indicates that disturbe key which do not disturbe end date.
- */
-const static std::string KEY_DO_NOT_DISTURB_END_DATE = "ans_doNotDisturbEndDate";
-
-/**
- * Indicates that disturbe key which enable all notification.
- */
-const static std::string KEY_ENABLE_ALL_NOTIFICATION = "ans_notificationAll";
-
-/**
- * Indicates that disturbe key which bundle label.
- */
-const static std::string KEY_BUNDLE_LABEL = "label_ans_bundle_";
-
-/**
- * Indicates that disturbe key which under line.
- */
-const static std::string KEY_UNDER_LINE = "_";
-
-/**
- * Indicates that disturbe key which bundle begin key.
- */
-const static std::string KEY_ANS_BUNDLE = "ans_bundle";
-
-/**
- * Indicates that disturbe key which bundle name.
- */
-const static std::string KEY_BUNDLE_NAME = "name";
-
-/**
- * Indicates that disturbe key which bundle imortance.
- */
-const static std::string KEY_BUNDLE_IMPORTANCE = "importance";
-
-/**
- * Indicates that disturbe key which bundle show badge.
- */
-const static std::string KEY_BUNDLE_SHOW_BADGE = "showBadge";
-
-/**
- * Indicates that disturbe key which bundle total badge num.
- */
-const static std::string KEY_BUNDLE_BADGE_TOTAL_NUM = "badgeTotalNum";
-
-/**
- * Indicates that disturbe key which bundle private allowed.
- */
-const static std::string KEY_BUNDLE_PRIVATE_ALLOWED = "privateAllowed";
-
-/**
- * Indicates that disturbe key which bundle enable notification.
- */
-const static std::string KEY_BUNDLE_ENABLE_NOTIFICATION = "enabledNotification";
-
-/**
- * Indicates that disturbe key which bundle popped dialog.
- */
-const static std::string KEY_BUNDLE_POPPED_DIALOG = "poppedDialog";
-
-/**
- * Indicates that disturbe key which bundle uid.
- */
-const static std::string KEY_BUNDLE_UID = "uid";
-
-/**
- * Indicates that disturbe key which group.
- */
-const static std::string KEY_GROUP = "group";
-
-/**
- * Indicates that disturbe key which group id.
- */
-const static std::string KEY_GROUP_ID = "id";
-
-/**
- * Indicates that disturbe key which group name.
- */
-const static std::string KEY_GROUP_NAME = "name";
-
-/**
- * Indicates that disturbe key which group description.
- */
-const static std::string KEY_GROUP_DESCRIPTION = "groupDescription";
-
-/**
- * Indicates that disturbe key which group is disable.
- */
-const static std::string KEY_GROUP_DISABLE = "isDisable";
-
-/**
- * Indicates that disturbe key which slot.
- */
-const static std::string KEY_SLOT = "slot";
-
-/**
- * Indicates that disturbe key which slot type.
- */
-const static std::string KEY_SLOT_TYPE = "type";
-
-/**
- * Indicates that disturbe key which slot id.
- */
-const static std::string KEY_SLOT_ID = "id";
-
-/**
- * Indicates that disturbe key which slot group id.
- */
-const static std::string KEY_SLOT_GROUPID = "groupId";
-
-/**
- * Indicates that disturbe key which slot group name.
- */
-const static std::string KEY_SLOT_NAME = "name";
-
-/**
- * Indicates that disturbe key which slot description.
- */
-const static std::string KEY_SLOT_DESCRIPTION = "description";
-
-/**
- * Indicates that disturbe key which slot level.
- */
-const static std::string KEY_SLOT_LEVEL = "level";
-
-/**
- * Indicates that disturbe key which slot show badge.
- */
-const static std::string KEY_SLOT_SHOW_BADGE = "showBadge";
-
-/**
- * Indicates that disturbe key which slot enable light.
- */
-const static std::string KEY_SLOT_ENABLE_LIGHT = "enableLight";
-
-/**
- * Indicates that disturbe key which slot enable vibration.
- */
-const static std::string KEY_SLOT_ENABLE_VRBRATION = "enableVibration";
-
-/**
- * Indicates that disturbe key which slot led light color.
- */
-const static std::string KEY_SLOT_LED_LIGHT_COLOR = "ledLightColor";
-
-/**
- * Indicates that disturbe key which slot lockscreen visibleness.
- */
-const static std::string KEY_SLOT_LOCKSCREEN_VISIBLENESS = "lockscreenVisibleness";
-
-/**
- * Indicates that disturbe key which slot sound.
- */
-const static std::string KEY_SLOT_SOUND = "sound";
-
-/**
- * Indicates that disturbe key which slot vibration style.
- */
-const static std::string KEY_SLOT_VIBRATION_STYLE = "vibrationSytle";
-
-/**
- * Indicates that disturbe key which slot enable bypass end.
- */
-const static std::string KEY_SLOT_ENABLE_BYPASS_DND = "enableBypassDnd";
-
-/**
- * Indicates whether the type of slot is enabled.
- */
-const static std::string KEY_SLOT_ENABLED = "enabled";
-
 /**
  * Indicates distributed database app id.
  */
-const std::string APP_ID = "advanced_notification_service";
+constexpr char APP_ID[] = "advanced_notification_service";
 
 /**
  * Indicates distributed database store id.
  */
-const std::string STORE_ID = "local_db";
+constexpr char STORE_ID[] = "local_db";
 
 /**
  * Default params that bundle importance is LEVEL_DEFAULT.
diff --git a/services/ans/src/notification_preferences_database.cpp b/services/ans/src/notification_preferences_database.cpp
index f98f9d5df7ed4bdc27f9746234ede98ff10a0470..842216dbbea9c3e0cae10fecfa63f07b156401bd 100644
--- a/services/ans/src/notification_preferences_database.cpp
+++ b/services/ans/src/notification_preferences_database.cpp
@@ -23,6 +23,186 @@
 #include "uri.h"
 namespace OHOS {
 namespace Notification {
+/**
+ * Indicates that disturbe key which do not disturbe type.
+ */
+const static std::string KEY_DO_NOT_DISTURB_TYPE = "ans_doNotDisturbType";
+
+/**
+ * Indicates that disturbe key which do not disturbe begin date.
+ */
+const static std::string KEY_DO_NOT_DISTURB_BEGIN_DATE = "ans_doNotDisturbBeginDate";
+
+/**
+ * Indicates that disturbe key which do not disturbe end date.
+ */
+const static std::string KEY_DO_NOT_DISTURB_END_DATE = "ans_doNotDisturbEndDate";
+
+/**
+ * Indicates that disturbe key which enable all notification.
+ */
+const static std::string KEY_ENABLE_ALL_NOTIFICATION = "ans_notificationAll";
+
+/**
+ * Indicates that disturbe key which bundle label.
+ */
+const static std::string KEY_BUNDLE_LABEL = "label_ans_bundle_";
+
+/**
+ * Indicates that disturbe key which under line.
+ */
+const static std::string KEY_UNDER_LINE = "_";
+
+/**
+ * Indicates that disturbe key which bundle begin key.
+ */
+const static std::string KEY_ANS_BUNDLE = "ans_bundle";
+
+/**
+ * Indicates that disturbe key which bundle name.
+ */
+const static std::string KEY_BUNDLE_NAME = "name";
+
+/**
+ * Indicates that disturbe key which bundle imortance.
+ */
+const static std::string KEY_BUNDLE_IMPORTANCE = "importance";
+
+/**
+ * Indicates that disturbe key which bundle show badge.
+ */
+const static std::string KEY_BUNDLE_SHOW_BADGE = "showBadge";
+
+/**
+ * Indicates that disturbe key which bundle total badge num.
+ */
+const static std::string KEY_BUNDLE_BADGE_TOTAL_NUM = "badgeTotalNum";
+
+/**
+ * Indicates that disturbe key which bundle private allowed.
+ */
+const static std::string KEY_BUNDLE_PRIVATE_ALLOWED = "privateAllowed";
+
+/**
+ * Indicates that disturbe key which bundle enable notification.
+ */
+const static std::string KEY_BUNDLE_ENABLE_NOTIFICATION = "enabledNotification";
+
+/**
+ * Indicates that disturbe key which bundle popped dialog.
+ */
+const static std::string KEY_BUNDLE_POPPED_DIALOG = "poppedDialog";
+
+/**
+ * Indicates that disturbe key which bundle uid.
+ */
+const static std::string KEY_BUNDLE_UID = "uid";
+
+/**
+ * Indicates that disturbe key which group.
+ */
+const static std::string KEY_GROUP = "group";
+
+/**
+ * Indicates that disturbe key which group id.
+ */
+const static std::string KEY_GROUP_ID = "id";
+
+/**
+ * Indicates that disturbe key which group name.
+ */
+const static std::string KEY_GROUP_NAME = "name";
+
+/**
+ * Indicates that disturbe key which group description.
+ */
+const static std::string KEY_GROUP_DESCRIPTION = "groupDescription";
+
+/**
+ * Indicates that disturbe key which group is disable.
+ */
+const static std::string KEY_GROUP_DISABLE = "isDisable";
+
+/**
+ * Indicates that disturbe key which slot.
+ */
+const static std::string KEY_SLOT = "slot";
+
+/**
+ * Indicates that disturbe key which slot type.
+ */
+const static std::string KEY_SLOT_TYPE = "type";
+
+/**
+ * Indicates that disturbe key which slot id.
+ */
+const static std::string KEY_SLOT_ID = "id";
+
+/**
+ * Indicates that disturbe key which slot group id.
+ */
+const static std::string KEY_SLOT_GROUPID = "groupId";
+
+/**
+ * Indicates that disturbe key which slot group name.
+ */
+const static std::string KEY_SLOT_NAME = "name";
+
+/**
+ * Indicates that disturbe key which slot description.
+ */
+const static std::string KEY_SLOT_DESCRIPTION = "description";
+
+/**
+ * Indicates that disturbe key which slot level.
+ */
+const static std::string KEY_SLOT_LEVEL = "level";
+
+/**
+ * Indicates that disturbe key which slot show badge.
+ */
+const static std::string KEY_SLOT_SHOW_BADGE = "showBadge";
+
+/**
+ * Indicates that disturbe key which slot enable light.
+ */
+const static std::string KEY_SLOT_ENABLE_LIGHT = "enableLight";
+
+/**
+ * Indicates that disturbe key which slot enable vibration.
+ */
+const static std::string KEY_SLOT_ENABLE_VRBRATION = "enableVibration";
+
+/**
+ * Indicates that disturbe key which slot led light color.
+ */
+const static std::string KEY_SLOT_LED_LIGHT_COLOR = "ledLightColor";
+
+/**
+ * Indicates that disturbe key which slot lockscreen visibleness.
+ */
+const static std::string KEY_SLOT_LOCKSCREEN_VISIBLENESS = "lockscreenVisibleness";
+
+/**
+ * Indicates that disturbe key which slot sound.
+ */
+const static std::string KEY_SLOT_SOUND = "sound";
+
+/**
+ * Indicates that disturbe key which slot vibration style.
+ */
+const static std::string KEY_SLOT_VIBRATION_STYLE = "vibrationSytle";
+
+/**
+ * Indicates that disturbe key which slot enable bypass end.
+ */
+const static std::string KEY_SLOT_ENABLE_BYPASS_DND = "enableBypassDnd";
+
+/**
+ * Indicates whether the type of slot is enabled.
+ */
+const static std::string KEY_SLOT_ENABLED = "enabled";
+
 const std::map<std::string,
     std::function<void(NotificationPreferencesDatabase *, sptr<NotificationSlot> &, std::string &)>>
     NotificationPreferencesDatabase::slotMap_ = {