Fix: filed_map was incorrectly persisted (#7443)

### What problem does this PR solve?

Fix `filed_map` was incorrectly persisted. #7412 

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

api/db/services/document_service.py

@@ -97,6 +97,26 @@ class DocumentService(CommonService):
 
         return list(docs.dicts()), count
 
+    @classmethod
+    @DB.connection_context()
+    def count_by_kb_id(cls, kb_id, keywords, run_status, types):
+        if keywords:
+            docs = cls.model.select().where(
+                (cls.model.kb_id == kb_id),
+                (fn.LOWER(cls.model.name).contains(keywords.lower()))
+            )
+        else:
+            docs = cls.model.select().where(cls.model.kb_id == kb_id)
+
+        if run_status:
+            docs = docs.where(cls.model.run.in_(run_status))
+        if types:
+            docs = docs.where(cls.model.type.in_(types))
+
+        count = docs.count()
+
+        return count
+
     @classmethod
     @DB.connection_context()
     def insert(cls, doc):

api/db/services/knowledgebase_service.py

@@ -269,6 +269,16 @@ class KnowledgebaseService(CommonService):
         dfs_update(m.parser_config, config)
         cls.update_by_id(id, {"parser_config": m.parser_config})
 
+    @classmethod
+    @DB.connection_context()
+    def delete_field_map(cls, id):
+        e, m = cls.get_by_id(id)
+        if not e:
+            raise LookupError(f"knowledgebase({id}) not found.")
+
+        m.parser_config.pop("field_map", None)
+        cls.update_by_id(id, {"parser_config": m.parser_config})
+
     @classmethod
     @DB.connection_context()
     def get_field_map(cls, ids):