diff --git a/source/src/main/java/one/nem/lacerta/source/database/entity/Library.java b/source/src/main/java/one/nem/lacerta/source/database/entity/Library.java
index 091087e4..6220fca1 100644
--- a/source/src/main/java/one/nem/lacerta/source/database/entity/Library.java
+++ b/source/src/main/java/one/nem/lacerta/source/database/entity/Library.java
@@ -1,4 +1,15 @@
 package one.nem.lacerta.source.database.entity;
 
+import androidx.room.Entity;
+import androidx.room.PrimaryKey;
+
+@Entity(tableName = "library")
 public class Library {
+
+    @PrimaryKey
+    public String id; // ドキュメントID
+
+    public String rootPath; // rootのパス
+
+    public String path; // パス
 }