diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Comment.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Comment.kt
new file mode 100644
index 0000000..558e2f2
--- /dev/null
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Comment.kt
@@ -0,0 +1,22 @@
+package cn.edu.hfut.auto.knowledge.entity
+
+import org.babyfish.jimmer.sql.Entity
+import org.babyfish.jimmer.sql.GeneratedValue
+import org.babyfish.jimmer.sql.Id
+import org.babyfish.jimmer.sql.ManyToOne
+import org.babyfish.jimmer.sql.meta.UUIDIdGenerator
+import java.time.LocalDateTime
+import java.util.*
+
+@Entity
+interface Comment {
+    @Id
+    @GeneratedValue(generatorType = UUIDIdGenerator::class)
+    val id: UUID
+    val content: String
+    @ManyToOne
+    val author: User
+    @ManyToOne
+    val note: Note
+    val createTime: LocalDateTime
+}
\ No newline at end of file
diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Knowledge.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Knowledge.kt
new file mode 100644
index 0000000..969ef9d
--- /dev/null
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Knowledge.kt
@@ -0,0 +1,44 @@
+package cn.edu.hfut.auto.knowledge.entity
+
+import org.babyfish.jimmer.sql.*
+import org.babyfish.jimmer.sql.kt.fetcher.newFetcher
+import org.babyfish.jimmer.sql.meta.UUIDIdGenerator
+import java.time.LocalDateTime
+import java.util.*
+
+@Entity
+interface Knowledge {
+    @Id
+    @GeneratedValue(generatorType = UUIDIdGenerator::class)
+    val id: UUID
+    @Key
+    val name: String
+    val createTime: LocalDateTime
+
+    @ManyToOne
+    @Key
+    val parent: Knowledge?
+
+    @OneToMany(mappedBy = "parent")
+    val children: List<Knowledge>
+
+    @OneToOne(mappedBy = "knowledge")
+    val knowledgeFileAttribute: KnowledgeFileAttribute?
+
+    companion object {
+        val BRIEF_FETCHER = newFetcher(Knowledge::class).by {
+            allScalarFields()
+            knowledgeFileAttribute()
+        }
+        val AS_PARENT_FETCHER = newFetcher(Knowledge::class).by {
+            allScalarFields()
+            children(BRIEF_FETCHER)
+            knowledgeFileAttribute()
+        }
+        val AS_CHILD_FETCHER = newFetcher(Knowledge::class).by {
+            allScalarFields()
+            parent(BRIEF_FETCHER)
+            knowledgeFileAttribute()
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/KnowledgeFileAttribute.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/KnowledgeFileAttribute.kt
new file mode 100644
index 0000000..8cb9e0c
--- /dev/null
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/KnowledgeFileAttribute.kt
@@ -0,0 +1,30 @@
+package cn.edu.hfut.auto.knowledge.entity
+
+import org.babyfish.jimmer.sql.*
+import org.babyfish.jimmer.sql.meta.UUIDIdGenerator
+import java.util.*
+
+@Entity
+interface KnowledgeFileAttribute {
+    @Id
+    @GeneratedValue(generatorType = UUIDIdGenerator::class)
+    val id: UUID
+    val suffix: String
+    val size: Long
+    val brief: String
+    val pageView: Long
+
+    @OneToOne
+    val knowledge: Knowledge
+
+    @ManyToMany
+    @JoinTable
+    val tags: List<Tag>
+
+    @ManyToMany
+    @JoinTable(name = "knowledge_file_attribute_starer_mapping")
+    val starers: List<User>
+
+    @ManyToMany(mappedBy = "knowledgeFiles")
+    val notes: List<Note>
+}
\ No newline at end of file
diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Note.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Note.kt
new file mode 100644
index 0000000..8c816e9
--- /dev/null
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Note.kt
@@ -0,0 +1,39 @@
+package cn.edu.hfut.auto.knowledge.entity
+
+import org.babyfish.jimmer.sql.*
+import org.babyfish.jimmer.sql.meta.UUIDIdGenerator
+import java.time.LocalDateTime
+import java.util.*
+
+@Entity
+interface Note {
+    @Id
+    @GeneratedValue(generatorType = UUIDIdGenerator::class)
+    val id: UUID
+    val title: String
+
+    @ManyToOne
+    val author: User
+    val createTime: LocalDateTime
+    val updateTime: LocalDateTime
+    val pageView: Long
+
+    @OneToMany(mappedBy = "note")
+    val comments: List<Comment>
+
+    @ManyToMany
+    @JoinTable
+    val tags: List<Tag>
+
+    @ManyToMany
+    @JoinTable(name = "note_knowledge_file_mapping")
+    val knowledgeFiles: List<KnowledgeFileAttribute>
+
+    @ManyToMany
+    @JoinTable(name = "note_starer_mapping")
+    val starers: List<User>
+
+    @ManyToMany
+    @JoinTable(name = "note_liker_mapping")
+    val likers: List<User>
+}
\ No newline at end of file
diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Notice.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Notice.kt
new file mode 100644
index 0000000..74ce10b
--- /dev/null
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Notice.kt
@@ -0,0 +1,24 @@
+package cn.edu.hfut.auto.knowledge.entity
+
+import org.babyfish.jimmer.sql.Entity
+import org.babyfish.jimmer.sql.GeneratedValue
+import org.babyfish.jimmer.sql.Id
+import org.babyfish.jimmer.sql.ManyToOne
+import org.babyfish.jimmer.sql.meta.UUIDIdGenerator
+import java.time.LocalDateTime
+import java.util.*
+
+@Entity
+interface Notice {
+    @Id
+    @GeneratedValue(generatorType = UUIDIdGenerator::class)
+    val id: UUID
+    val viewed: Boolean
+    val createTime: LocalDateTime
+    @ManyToOne
+    val note: Note
+    @ManyToOne
+    val comment: Comment
+    @ManyToOne
+    val targetUser: User
+}
\ No newline at end of file
diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Tag.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Tag.kt
new file mode 100644
index 0000000..88e3d4b
--- /dev/null
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/Tag.kt
@@ -0,0 +1,14 @@
+package cn.edu.hfut.auto.knowledge.entity
+
+import org.babyfish.jimmer.sql.Entity
+import org.babyfish.jimmer.sql.GeneratedValue
+import org.babyfish.jimmer.sql.GenerationType
+import org.babyfish.jimmer.sql.Id
+
+@Entity
+interface Tag {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    val id: Long
+    val name: String
+}
\ No newline at end of file
diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/User.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/User.kt
index 56faea9..e9f95ec 100644
--- a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/User.kt
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/User.kt
@@ -9,9 +9,23 @@ interface User {
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     val id: Long
+
     @Key
     val username: String
+
     @get:JsonIgnore
     val password: String
     val level: Short
+
+    @OneToMany(mappedBy = "author")
+    val notes: List<Note>
+
+    @OneToMany(mappedBy = "targetUser")
+    val notices: List<Notice>
+
+    @ManyToMany(mappedBy = "starers")
+    val starredKnowledge: List<KnowledgeFileAttribute>
+
+    @ManyToMany(mappedBy = "starers")
+    val starredNotes: List<Note>
 }
\ No newline at end of file