diff --git a/core/src/main/java/com/databasir/core/domain/document/diff/DiffTypePredictor.java b/core/src/main/java/com/databasir/core/domain/document/diff/DiffTypePredictor.java
new file mode 100644
index 0000000..7e4c006
--- /dev/null
+++ b/core/src/main/java/com/databasir/core/domain/document/diff/DiffTypePredictor.java
@@ -0,0 +1,31 @@
+package com.databasir.core.domain.document.diff;
+
+import com.databasir.core.diff.data.DiffType;
+import com.databasir.core.domain.document.data.DatabaseDocumentSimpleResponse;
+
+import java.util.List;
+
+public class DiffTypePredictor {
+
+    public static DiffType predict(List<DatabaseDocumentSimpleResponse.TableData> result) {
+        long changedItemSize = result.stream()
+                .filter(item -> !item.getDiffType().isNone())
+                .count();
+        long addedItemSize = result.stream()
+                .filter(item -> !item.getDiffType().isNone())
+                .filter(item -> item.getDiffType().isAdded())
+                .count();
+        long removedItemSize = result.stream()
+                .filter(item -> !item.getDiffType().isNone())
+                .filter(item -> item.getDiffType().isRemoved())
+                .count();
+        if (changedItemSize > 0 && addedItemSize == changedItemSize) {
+            return DiffType.ADDED;
+        } else if (changedItemSize > 0 && removedItemSize == changedItemSize) {
+            return DiffType.REMOVED;
+        } else {
+            return result.stream()
+                    .anyMatch(t -> t.getDiffType() != DiffType.NONE) ? DiffType.MODIFIED : DiffType.NONE;
+        }
+    }
+}
diff --git a/core/src/main/java/com/databasir/core/domain/document/service/DocumentService.java b/core/src/main/java/com/databasir/core/domain/document/service/DocumentService.java
index 3edb3ec..f018eb7 100644
--- a/core/src/main/java/com/databasir/core/domain/document/service/DocumentService.java
+++ b/core/src/main/java/com/databasir/core/domain/document/service/DocumentService.java
@@ -13,6 +13,7 @@ import com.databasir.core.domain.document.comparator.TableDiffResult;
 import com.databasir.core.domain.document.converter.*;
 import com.databasir.core.domain.document.data.*;
 import com.databasir.core.domain.document.data.TableDocumentResponse.ForeignKeyDocumentResponse;
+import com.databasir.core.domain.document.diff.DiffTypePredictor;
 import com.databasir.core.domain.document.event.DocumentUpdated;
 import com.databasir.core.domain.document.generator.DocumentFileGenerator;
 import com.databasir.core.domain.document.generator.DocumentFileGenerator.DocumentFileGenerateContext;
@@ -274,16 +275,7 @@ public class DocumentService {
                     }
                 }
                 result.sort(Comparator.comparing(DatabaseDocumentSimpleResponse.TableData::getName));
-                var notNoneDiffs = result.stream().filter(item -> !item.getDiffType().isNone());
-                boolean allAdded = notNoneDiffs.count() > 0
-                        && notNoneDiffs.allMatch(item -> item.getDiffType().isAdded());
-                DiffType diffType;
-                if (allAdded) {
-                    diffType = DiffType.ADDED;
-                } else {
-                    diffType = result.stream()
-                            .anyMatch(t -> t.getDiffType() != DiffType.NONE) ? DiffType.MODIFIED : DiffType.NONE;
-                }
+                DiffType diffType = DiffTypePredictor.predict(result);
                 return documentSimpleResponseConverter.of(document, result, diffType, projectName);
             } else {
                 tableMetas.sort(Comparator.comparing(DatabaseDocumentSimpleResponse.TableData::getName));
diff --git a/meta/src/main/java/com/databasir/core/diff/data/DiffType.java b/meta/src/main/java/com/databasir/core/diff/data/DiffType.java
index 20f2423..2113af5 100644
--- a/meta/src/main/java/com/databasir/core/diff/data/DiffType.java
+++ b/meta/src/main/java/com/databasir/core/diff/data/DiffType.java
@@ -11,6 +11,10 @@ public enum DiffType {
         return this == ADDED;
     }
 
+    public boolean isRemoved() {
+        return this == REMOVED;
+    }
+
     public boolean isNone() {
         return this == NONE;
     }