Не выполняется запрос INSERT в c#

Если создать вот такой класс Слово

public class Word
{
    public int Id { get; set; }
    public string Eng { get; set; }
    public string Rus { get; set; }
    public override string ToString()
    {
        return $"{Id}: {Eng}-{Rus}";
    }
}

То для него получился вот такой класс Хранилища

public class Repository
{
    //ctor
    public Repository()
    {
    }
    private OleDbConnection GetConnection()
    {
        OleDbConnectionStringBuilder oleStringBuilder = new OleDbConnectionStringBuilder();
        oleStringBuilder.Provider = "Microsoft.ACE.OLEDB.12.0";
        var currentDir = Path.GetDirectoryName(this.GetType().Assembly.Location);
        oleStringBuilder.DataSource = Path.Combine(currentDir, "wordsDb.accdb");
        OleDbConnection connection = new OleDbConnection(oleStringBuilder.ConnectionString);
        return connection;
    }
    /// <summary>
    /// Получение полного списка всех слов
    /// </summary>
    /// <returns></returns>
    public List<Word> GetWords()
    {
        var result = new List<Word>();
        using (OleDbConnection connection = GetConnection())
        using (OleDbCommand command = connection.CreateCommand())
        {
            command.CommandText = "SELECT * FROM Words";
            connection.Open();
            var reader = command.ExecuteReader();
            while (reader.Read())
            {
                var word = new Word
                {
                    Id = reader.GetFieldValue<int>(0),
                    Eng = reader.GetFieldValue<string>(1),
                    Rus = reader.GetFieldValue<string>(2)
                };
                result.Add(word);
            }
        }
        return result;
    }
    /// <summary>
    /// Поиск слова по его Id
    /// </summary>
    /// <param name="id"></param>
    /// <returns></returns>
    public Word GetWordById(int id)
    {
        Word result = null;
        using (OleDbConnection connection = GetConnection())
        using (OleDbCommand command = connection.CreateCommand())
        {
            command.CommandText = "SELECT * FROM Words WHERE Id=@id";
            command.Parameters.AddWithValue("id", id);
            connection.Open();
            var reader = command.ExecuteReader();
            while (reader.Read())
            {
                result = new Word
                {
                    Id = reader.GetFieldValue<int>(0),
                    Eng = reader.GetFieldValue<string>(1),
                    Rus = reader.GetFieldValue<string>(2)
                };
            }
        }
        return result;
    }
    /// <summary>
    /// Поиск слова по анг. значению
    /// </summary>
    /// <param name="eng"></param>
    /// <returns></returns>
    public Word GetWordByEng(string eng)
    {
        if (String.IsNullOrEmpty(eng)) throw new ArgumentNullException(nameof(eng));
        Word result = null;
        using (OleDbConnection connection = GetConnection())
        using (OleDbCommand command = connection.CreateCommand())
        {
            command.CommandText = "SELECT * FROM Words WHERE english=@eng";
            command.Parameters.AddWithValue("eng", eng);
            connection.Open();
            var reader = command.ExecuteReader();
            while (reader.Read())
            {
                result = new Word
                {
                    Id = reader.GetFieldValue<int>(0),
                    Eng = reader.GetFieldValue<string>(1),
                    Rus = reader.GetFieldValue<string>(2)
                };
            }
        }
        return result;
    }
    /// <summary>
    /// Добавление нового слова
    /// </summary>
    /// <param name="word"></param>
    /// <returns></returns>
    public int AddWord(Word word)
    {
        if (word == null) throw new ArgumentNullException(nameof(word));
        if (String.IsNullOrWhiteSpace(word.Eng)) throw new ArgumentException("Английское значение обязательное");
        if (String.IsNullOrWhiteSpace(word.Rus)) throw new ArgumentException("Русское значение обязательное");
        int result = 0;
        using (OleDbConnection connection = GetConnection())
        using (OleDbCommand command = connection.CreateCommand())
        {
            command.CommandText = "INSERT INTO Words (english, russian) VALUES (@eng, @rus)";
            command.Parameters.AddWithValue("eng", word.Eng);
            command.Parameters.AddWithValue("rus", word.Rus);
            connection.Open();
            result = command.ExecuteNonQuery();
        }
        return result;
    }
    /// <summary>
    /// Обновление слова
    /// </summary>
    /// <param name="word"></param>
    /// <returns></returns>
    public int UpdateWord(Word word)
    {
        if (word == null) throw new ArgumentNullException(nameof(word));
        if (word.Id == 0) throw new ArgumentException(nameof(word));
        int result = 0;
        using (OleDbConnection connection = GetConnection())
        using (OleDbCommand command = connection.CreateCommand())
        {
            command.CommandText = $"UPDATE Words SET english = '{word.Eng}', russian = '{word.Rus}' WHERE Id = {word.Id}";
            connection.Open();
            result = command.ExecuteNonQuery();
        }
        return result;
    }

    /// <summary>
    /// Удаление слова
    /// </summary>
    /// <param name="id"></param>
    /// <returns></returns>
    public int DeleteWord(int id)
    {
        int result = 0;
        using (OleDbConnection connection = GetConnection())
        using (OleDbCommand command = connection.CreateCommand())
        {
            command.CommandText = "DELETE FROM Words WHERE Id=@id";
            command.Parameters.AddWithValue("id", id);
            connection.Open();
            result = command.ExecuteNonQuery();
        }
        return result;
    }
}

Как таким классом пользоваться можете посмотреть через тесты

[TestClass()]
public class RepositoryTests
{
    [TestMethod()]
    public void GetAllWords()
    {
        Repository repo = new Repository();
        var res = repo.GetWords();
        Assert.IsTrue(res.Count > 0);
    }
    [TestMethod]
    public void GetWordByEng()
    {
        Repository repo = new Repository();
        string eng = "apple";
        Word word = repo.GetWordByEng(eng);
        Assert.IsNotNull(word);
        Assert.AreEqual(eng, word.Eng);
    }
    [TestMethod]
    public void GetWordById()
    {
        Repository repo = new Repository();
        string eng = "apple";
        int id = 1;
        Word word = repo.GetWordById(id);
        Assert.IsNotNull(word);
        Assert.AreEqual(eng, word.Eng);
    }
    [TestMethod]
    [Ignore]
    public void InsertWord()
    {
        var word = new Word { Eng = "test", Rus = "тест" };
        Repository repo = new Repository();
        int res = repo.AddWord(word);
        Assert.IsTrue(res > 0);
    }
    [TestMethod]
    [Ignore]
    public void UpdateWord()
    {
        var rus = "тестОбновлен";
        Repository repo = new Repository();
        var word = repo.GetWordByEng("test");
        word.Eng = word.Eng + 1;
        word.Rus = rus;
        int res = repo.UpdateWord(word);
        var updatedWord = repo.GetWordById(word.Id);
        Assert.IsTrue(res > 0);
        Assert.AreEqual(rus, updatedWord.Rus);
    }
    [TestMethod]
    [Ignore]
    public void DeleteWord()
    {
        Repository repo = new Repository();
        var word = repo.GetWordByEng("test1");
        int res = repo.DeleteWord(word.Id);
        Assert.IsTrue(res > 0);
    }
}