diff --git a/kernel/model/attribute_view.go b/kernel/model/attribute_view.go
index 19961289c..e92d4ecad 100644
--- a/kernel/model/attribute_view.go
+++ b/kernel/model/attribute_view.go
@@ -806,38 +806,47 @@ func updateAttributeViewColRelation(operation *Operation) (err error) {
 	}
 
 	for _, keyValues := range srcAv.KeyValues {
-		if keyValues.Key.ID == operation.KeyID {
-			// 已经设置过双向关联的话需要先断开双向关联
-			if nil != keyValues.Key.Relation && keyValues.Key.Relation.IsTwoWay {
-				oldDestAv, parseErr := av.ParseAttributeView(keyValues.Key.Relation.AvID)
-				if nil == parseErr {
-					isOldSameAv := oldDestAv.ID == destAv.ID
-					if isOldSameAv {
-						oldDestAv = destAv
-					}
+		if keyValues.Key.ID != operation.KeyID {
+			continue
+		}
 
-					oldDestKey, _ := oldDestAv.GetKey(keyValues.Key.Relation.BackKeyID)
-					if nil != oldDestKey && nil != oldDestKey.Relation && oldDestKey.Relation.AvID == srcAv.ID && oldDestKey.Relation.IsTwoWay {
-						oldDestKey.Relation.IsTwoWay = false
-						oldDestKey.Relation.BackKeyID = ""
-					}
+		srcRel := keyValues.Key.Relation
+		// 已经设置过双向关联的话需要先断开双向关联
+		if nil != srcRel && srcRel.IsTwoWay {
+			oldDestAv, _ := av.ParseAttributeView(srcRel.AvID)
+			if nil != oldDestAv {
+				isOldSameAv := oldDestAv.ID == destAv.ID
+				if isOldSameAv {
+					oldDestAv = destAv
+				}
 
-					if !isOldSameAv {
-						err = av.SaveAttributeView(oldDestAv)
-						if nil != err {
-							return
-						}
+				oldDestKey, _ := oldDestAv.GetKey(srcRel.BackKeyID)
+				if nil != oldDestKey && nil != oldDestKey.Relation && oldDestKey.Relation.AvID == srcAv.ID && oldDestKey.Relation.IsTwoWay {
+					oldDestKey.Relation.IsTwoWay = false
+					oldDestKey.Relation.BackKeyID = ""
+				}
+
+				if !isOldSameAv {
+					err = av.SaveAttributeView(oldDestAv)
+					if nil != err {
+						return
 					}
 				}
 			}
-
-			keyValues.Key.Relation = &av.Relation{
-				AvID:      operation.ID,
-				IsTwoWay:  operation.IsTwoWay,
-				BackKeyID: operation.BackRelationKeyID,
-			}
-			break
 		}
+
+		srcRel = &av.Relation{
+			AvID:     operation.ID,
+			IsTwoWay: operation.IsTwoWay,
+		}
+
+		if operation.IsTwoWay {
+			srcRel.BackKeyID = operation.BackRelationKeyID
+		} else {
+			srcRel.BackKeyID = ""
+		}
+
+		break
 	}
 
 	destAdded := false
diff --git a/kernel/model/export.go b/kernel/model/export.go
index 671dba184..3bc24bf16 100644
--- a/kernel/model/export.go
+++ b/kernel/model/export.go
@@ -818,6 +818,7 @@ func ProcessPDF(id, p string, merge, removeAssets bool) (err error) {
 
 	processPDFBookmarks(pdfCtx, headings)
 	processPDFLinkEmbedAssets(pdfCtx, assetDests, removeAssets)
+	// processPDFWatermark(pdfCtx, "text", "Test", "")
 
 	pdfcpu.VersionStr = "SiYuan v" + util.Ver
 	if writeErr := api.WriteContextFile(pdfCtx, p); nil != writeErr {
@@ -827,6 +828,46 @@ func ProcessPDF(id, p string, merge, removeAssets bool) (err error) {
 	return
 }
 
+func processPDFWatermark(pdfCtx *pdfcpu.Context, mode, watermark, desc string) {
+	// Support adding the watermark on export PDF https://github.com/siyuan-note/siyuan/issues/9961
+	// https://pdfcpu.io/core/watermark
+
+	if !IsPaidUser() {
+		return
+	}
+
+	if "" == watermark {
+		return
+	}
+
+	if "text" != mode && "image" != mode && "pdf" != mode {
+		logging.LogErrorf("invalid watermark type: %s", mode)
+		return
+	}
+
+	var wm *pdfcpu.Watermark
+	var err error
+	switch mode {
+	case "text":
+		wm, err = pdfcpu.ParseTextWatermarkDetails(watermark, desc, false, pdfcpu.POINTS)
+	case "image":
+		wm, err = pdfcpu.ParseImageWatermarkDetails(watermark, desc, false, pdfcpu.POINTS)
+	case "pdf":
+		wm, err = pdfcpu.ParsePDFWatermarkDetails(watermark, desc, false, pdfcpu.POINTS)
+	}
+
+	if nil != err {
+		logging.LogErrorf("parse watermark failed: %s", err)
+		return
+	}
+
+	err = pdfCtx.AddWatermarks(nil, wm)
+	if nil != err {
+		logging.LogErrorf("add watermark failed: %s", err)
+		return
+	}
+}
+
 func processPDFBookmarks(pdfCtx *pdfcpu.Context, headings []*ast.Node) {
 	links, err := api.ListToCLinks(pdfCtx)
 	if nil != err {