diff --git a/src/api/controller/accounts.py b/src/api/controller/accounts.py
index 8c98d22..a095b5e 100644
--- a/src/api/controller/accounts.py
+++ b/src/api/controller/accounts.py
@@ -46,30 +46,46 @@ def get_months(account_id):
 
 @app.route("/api/accounts", methods=["PUT"])
 def add_account():
-    account = Account(request.json['name'])
+    with session.begin():
+        try:
+            account = Account(request.json['name'])
 
-    session.add(account)
-    session.commit()
+            session.add(account)
+            session.commit()
+
+            return json.dumps("Account added.")
+        except:
+            session.rollback()
+            raise
 
-    return json.dumps("Account added.")
 
 @app.route("/api/accounts/<account_id>", methods=["PUT"])
 def update_account(account_id):
-    account = session.query(Account).filter(Account.id == account_id).first()
+    with session.begin():
+        try:
+            account = session.query(Account).filter(Account.id == account_id).first()
 
-    account.name = request.json['name']
+            account.name = request.json['name']
 
-    session.merge(account)
-    session.commit()
+            session.merge(account)
+            session.commit()
 
-    return json.dumps("Account #%s updated." % account_id)
+            return json.dumps("Account #%s updated." % account_id)
+        except:
+            session.rollback()
+            raise
 
 @app.route("/api/accounts/<account_id>", methods=["DELETE"])
 def delete_account(account_id):
-    account = session.query(Account).filter(Account.id == account_id).first()
-
-    session.delete(account)
-    session.commit()
-
-    return json.dumps("Account #%s deleted." % account_id)
+    with session.begin():
+        try:
+            account = session.query(Account).filter(Account.id == account_id).first()
+        
+            session.delete(account)
+            session.commit()
+        
+            return json.dumps("Account #%s deleted." % account_id)
+        except:
+            session.rollback()
+            raise
 
diff --git a/src/api/controller/entries.py b/src/api/controller/entries.py
index 262fe1d..21ee4eb 100644
--- a/src/api/controller/entries.py
+++ b/src/api/controller/entries.py
@@ -45,44 +45,58 @@ def get_entries(account_id, year, month):
 
 @app.route("/api/entries", methods=["PUT"])
 def add_entry():
-    entry = Entry(
-      value_date = request.json['value_date'],
-      operation_date = request.json['operation_date'],
-      label = request.json['label'],
-      value = request.json['value'],
-      category = request.json['category'],
-      account_id = request.json['account_id']
-    )
-
-    session.add(entry)
-    session.commit()
-
-    return json.dumps("Entry added.")
+    with session.begin():
+        try:
+            entry = Entry(
+              value_date = request.json['value_date'],
+              operation_date = request.json['operation_date'],
+              label = request.json['label'],
+              value = request.json['value'],
+              category = request.json['category'],
+              account_id = request.json['account_id']
+            )
+        
+            session.add(entry)
+            session.commit()
+        
+            return json.dumps("Entry added.")
+        except:
+            session.rollback()
+            raise
 
 @app.route("/api/entries/<entry_id>", methods=["PUT"])
 def update_entry(entry_id):
-    entry = session.query(Entry).filter(Entry.id == entry_id).first()
-
-    entry.id = entry_id
-    entry.value_date = request.json['value_date']
-    entry.operation_date = request.json['operation_date']
-    entry.label = request.json['label']
-    entry.value = request.json['value']
-    entry.category = request.json['category']
-    entry.account_id = request.json['account_id']
-
-    session.merge(entry)
-    session.commit()
-
-    return json.dumps("Entry #%s updated." % entry_id)
+    with session.begin():
+        try:
+            entry = session.query(Entry).filter(Entry.id == entry_id).first()
+        
+            entry.id = entry_id
+            entry.value_date = request.json['value_date']
+            entry.operation_date = request.json['operation_date']
+            entry.label = request.json['label']
+            entry.value = request.json['value']
+            entry.category = request.json['category']
+            entry.account_id = request.json['account_id']
+        
+            session.merge(entry)
+            session.commit()
+        
+            return json.dumps("Entry #%s updated." % entry_id)
+        except:
+            session.rollback()
+            raise
 
 @app.route("/api/entries/<entry_id>", methods=["DELETE"])
 def delete_entry(entry_id):
-    entry = session.query(Entry).filter(Entry.id == entry_id).first()
-
-    session.delete(entry)
-    session.commit()
-
-    return json.dumps("Entry #%s deleted." % entry_id)
-
+    with session.begin():
+        try:
+            entry = session.query(Entry).filter(Entry.id == entry_id).first()
+        
+            session.delete(entry)
+            session.commit()
+        
+            return json.dumps("Entry #%s deleted." % entry_id)
+        except:
+            session.rollback()
+            raise