Loop through Table and Insert data into database based on condition using C# in ASP.Net

Hi learningmrs,

Refer below code.

protected void Btnsubmit_Click1(object sender, EventArgs e)
{
    string id = txtEmp.Text;
    string effectiveDate = txteffdt.Text,
        action = txtAction.Text,
        actionReason = ddlActionReason.Text,
        status = "A/I";
    int effectiveSequence = 0;
    DataTable dt = GetData();
    DataRow[] dr = dt.Select("EmpId='" + id + "' AND Effdt='" + effectiveDate + "'");
    if (dr.Length > 0)
    {
        effectiveSequence = Convert.ToInt32(dt.Select("EmpId='" + id + "' AND Effdt='" + effectiveDate + "'")[0]["EffectiveSequence"]);
        string query = "INSERT INTO Employee VALUES(@EffectiveDate, @EffectiveSequence, @EmpID, @Action, @ActionReason, @Status)";
        using (SqlCommand cmd = new SqlCommand())
        {
            cmd.CommandText = query;
            cmd.Parameters.AddWithValue("@EffectiveDate", effectiveDate);
            cmd.Parameters.AddWithValue("@EffectiveSequence", effectiveSequence + 1);
            cmd.Parameters.AddWithValue("@EmpID", id);
            cmd.Parameters.AddWithValue("@Action", action);
            cmd.Parameters.AddWithValue("@ActionReason", actionReason);
            cmd.Parameters.AddWithValue("@Status", status);
            this.Insert(cmd);
        }
    }
    else
    {
        using (SqlCommand cmd = new SqlCommand())
        {
            string query = "INSERT INTO Employee VALUES(@EffectiveDate, @EffectiveSequence, @EmpID, @Action, @ActionReason, @Status)";
            cmd.CommandText = query;
            cmd.Parameters.AddWithValue("@EffectiveDate", effectiveDate);
            cmd.Parameters.AddWithValue("@EffectiveSequence", 0);
            cmd.Parameters.AddWithValue("@EmpID", id);
            cmd.Parameters.AddWithValue("@Action", action);
            cmd.Parameters.AddWithValue("@ActionReason", actionReason);
            cmd.Parameters.AddWithValue("@Status", status);
            this.Insert(cmd);
        }
    }

    DataRow[] drEmployees = dt.Select("EmpId='" + id + "'");
    foreach (DataRow row in drEmployees)
    {
        DataRow[] dr1 = dt.Select("Effdt='" + row["EffectiveDate"].ToString() + "'");
        using (SqlCommand cmd = new SqlCommand())
        {
            string query = "INSERT INTO Employee VALUES(@EffectiveDate, @EffectiveSequence, @EmpID, @Action, @ActionReason, @Status)";
            cmd.CommandText = query;
            cmd.Parameters.AddWithValue("@EffectiveDate", effectiveDate);
            cmd.Parameters.AddWithValue("@EmpID", id);
            cmd.Parameters.AddWithValue("@Action", action);
            cmd.Parameters.AddWithValue("@ActionReason", actionReason);
            cmd.Parameters.AddWithValue("@Status", status);
            effectiveSequence = Convert.ToInt32(dt.Select("Effdt='" + row["EffectiveDate"].ToString() + "'")[0]["EffectiveSequence"]);
            cmd.Parameters.AddWithValue("@EffectiveSequence", effectiveSequence + 1);
            this.Insert(cmd);
        }
    }
}

private DataTable GetData()
{
    string conString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    string query = "SELECT * FROM Employees";
    SqlCommand cmd = new SqlCommand(query);
    using (SqlConnection con = new SqlConnection(conString))
    {
        using (SqlDataAdapter sda = new SqlDataAdapter())
        {
            cmd.Connection = con;
            sda.SelectCommand = cmd;
            using (DataTable dt = new DataTable())
            {
                sda.Fill(dt);
                return dt;
            }
        }
    }
}

private void Insert(SqlCommand cmd)
{
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        cmd.Connection = con;
        con.Open();
        cmd.ExecuteScalar();
        con.Close();
    }
}