diff --git a/server.js b/server.js
index db0e005..7063f19 100644
--- a/server.js
+++ b/server.js
@@ -56,9 +56,40 @@ try {
 
 // Migration: Update CHECK constraint to include 'sickday' if needed
 try {
-  // SQLite doesn't support modifying CHECK constraints directly
-  // The constraint will be updated when a new sickday entry is added
-  console.log('Entry_type constraint check completed');
+  // SQLite can't alter CHECK constraints, so the table has to be rebuilt
+  const { sql } = db.prepare("SELECT sql FROM sqlite_master WHERE type = 'table' AND name = 'entries'").get();
+
+  if (!sql.includes("'sickday'")) {
+    console.log('Rebuilding entries table to allow sickday entries...');
+    const seq = db.prepare("SELECT seq FROM sqlite_sequence WHERE name = 'entries'").get();
+
+    db.transaction(() => {
+      db.exec(`
+        CREATE TABLE entries_new (
+          id INTEGER PRIMARY KEY AUTOINCREMENT,
+          date TEXT NOT NULL UNIQUE,
+          start_time TEXT,
+          end_time TEXT,
+          pause_minutes INTEGER NOT NULL DEFAULT 0,
+          location TEXT DEFAULT 'office' CHECK(location IN ('office', 'home')),
+          entry_type TEXT DEFAULT 'work' CHECK(entry_type IN ('work', 'vacation', 'flextime', 'sickday'))
+        )
+      `);
+      db.exec(`
+        INSERT INTO entries_new (id, date, start_time, end_time, pause_minutes, location, entry_type)
+        SELECT id, date, start_time, end_time, pause_minutes, location, entry_type FROM entries
+      `);
+      db.exec('DROP TABLE entries');
+      db.exec('ALTER TABLE entries_new RENAME TO entries');
+
+      // Keep the AUTOINCREMENT counter so ids of deleted entries are never reused
+      if (seq) {
+        db.prepare("UPDATE sqlite_sequence SET seq = ? WHERE name = 'entries'").run(seq.seq);
+      }
+    })();
+
+    console.log('Entries table rebuilt successfully');
+  }
 } catch (error) {
   console.error('Error during entry_type constraint migration:', error);
 }