diff --git a/src/main/java/io/khasang/pm/dao/BasicDao.java b/src/main/java/io/khasang/pm/dao/BasicDao.java
index 2e1675d..d254e88 100644
--- a/src/main/java/io/khasang/pm/dao/BasicDao.java
+++ b/src/main/java/io/khasang/pm/dao/BasicDao.java
@@ -11,8 +11,20 @@ public interface BasicDao<T> {
      */
     T add(T entity);
 
+    /**
+     * updating entity in db
+     *
+     * @param entity - entity for update in db
+     * @return udated entity
+     */
     T update(T entity);
 
+    /**
+     * deleting entity in db
+     *
+     * @param entity - entity for deleting from db
+     * @return deleted entity
+     */
     T delete(T entity);
 
     /**
diff --git a/src/main/java/io/khasang/pm/entity/ChildDocument.java b/src/main/java/io/khasang/pm/entity/ChildDocument.java
index 34954b2..9b47682 100644
--- a/src/main/java/io/khasang/pm/entity/ChildDocument.java
+++ b/src/main/java/io/khasang/pm/entity/ChildDocument.java
@@ -3,7 +3,6 @@
 import javax.persistence.*;
 
 @Entity
-//@Table(name = "documents")
 public class ChildDocument {
     @Id
     @GeneratedValue(strategy = GenerationType.AUTO)
diff --git a/src/main/java/io/khasang/pm/service/ChildDocumentService.java b/src/main/java/io/khasang/pm/service/ChildDocumentService.java
index 3acc4f3..2f686e8 100644
--- a/src/main/java/io/khasang/pm/service/ChildDocumentService.java
+++ b/src/main/java/io/khasang/pm/service/ChildDocumentService.java
@@ -5,13 +5,42 @@
 import java.util.List;
 
 public interface ChildDocumentService {
+    /**
+     * required for adding childDocument to db
+     *
+     * @param childDocument - childDocument for adding
+     * @return added childDocument
+     */
     ChildDocument add(ChildDocument childDocument);
 
+    /**
+     * required for updating childDocument in db
+     *
+     * @param childDocument - childDocument for update
+     * @return updated childDocument
+     */
     ChildDocument update(ChildDocument childDocument);
 
+    /**
+     * required for deleting childDocument from db
+     *
+     * @param id - childDocument's id for deleting
+     * @return deleted childDocument
+     */
     ChildDocument delete(long id);
 
+    /**
+     * getting specify childDocument by ID from db
+     *
+     * @param id - childDocument's id for receiving
+     * @return childDocument by id
+     */
     ChildDocument getById(long id);
 
+    /**
+     * getting all childDocuments
+     *
+     * @return all childDocument from db
+     */
     List<ChildDocument> getAllChildDocuments();
 }