diff --git a/prisma/migrations/20260114125000_add_calendar_sync/migration.sql b/prisma/migrations/20260114125000_add_calendar_sync/migration.sql
index 28a29c0..736f16a 100644
--- a/prisma/migrations/20260114125000_add_calendar_sync/migration.sql
+++ b/prisma/migrations/20260114125000_add_calendar_sync/migration.sql
@@ -9,7 +9,7 @@ BEGIN
     END IF;
 END $$;
 
--- CreateTable
+-- CreateTable: Create CalendarSync table if it doesn't exist
 CREATE TABLE IF NOT EXISTS "CalendarSync" (
     "id" TEXT NOT NULL,
     "calendarId" TEXT NOT NULL,
@@ -42,7 +42,7 @@ CREATE INDEX IF NOT EXISTS "CalendarSync_provider_idx" ON "CalendarSync"("provid
 -- CreateIndex
 CREATE INDEX IF NOT EXISTS "Calendar_missionId_idx" ON "Calendar"("missionId");
 
--- AddForeignKey: Add foreign key if it doesn't exist
+-- AddForeignKey: Add Calendar_missionId_fkey if it doesn't exist
 DO $$ 
 BEGIN
     IF NOT EXISTS (
@@ -53,8 +53,24 @@ BEGIN
     END IF;
 END $$;
 
--- AddForeignKey
-ALTER TABLE "CalendarSync" ADD CONSTRAINT "CalendarSync_calendarId_fkey" FOREIGN KEY ("calendarId") REFERENCES "Calendar"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+-- AddForeignKey: Add CalendarSync_calendarId_fkey if it doesn't exist
+DO $$ 
+BEGIN
+    IF NOT EXISTS (
+        SELECT 1 FROM pg_constraint 
+        WHERE conname = 'CalendarSync_calendarId_fkey'
+    ) THEN
+        ALTER TABLE "CalendarSync" ADD CONSTRAINT "CalendarSync_calendarId_fkey" FOREIGN KEY ("calendarId") REFERENCES "Calendar"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+    END IF;
+END $$;
 
--- AddForeignKey
-ALTER TABLE "CalendarSync" ADD CONSTRAINT "CalendarSync_mailCredentialId_fkey" FOREIGN KEY ("mailCredentialId") REFERENCES "MailCredentials"("id") ON DELETE SET NULL ON UPDATE CASCADE;
+-- AddForeignKey: Add CalendarSync_mailCredentialId_fkey if it doesn't exist
+DO $$ 
+BEGIN
+    IF NOT EXISTS (
+        SELECT 1 FROM pg_constraint 
+        WHERE conname = 'CalendarSync_mailCredentialId_fkey'
+    ) THEN
+        ALTER TABLE "CalendarSync" ADD CONSTRAINT "CalendarSync_mailCredentialId_fkey" FOREIGN KEY ("mailCredentialId") REFERENCES "MailCredentials"("id") ON DELETE SET NULL ON UPDATE CASCADE;
+    END IF;
+END $$;