/// <summary>
/// OData function for clearing log records.
/// </summary>
/// <param name="dateTime">Stringed <see cref="DateTimeOffset"/> date. Delete all records older that date.</param>
/// <returns>Success operation return <c>true</c>.</returns>
private static bool ClearLogRecords(string dateTime)
{
DateTimeOffset date;
if (!DateTimeOffset.TryParse(dateTime, out date))
{
throw new ArgumentException("Invalid date format", nameof(dateTime));
}
SQLDataService ds = (SQLDataService)DataServiceProvider.DataService;
IDbConnection connection = ds.GetConnection();
connection.Open();
try
{
IDbCommand command = connection.CreateCommand();
string tableName = Information.GetClassStorageName(typeof(ApplicationLog));
string timestampColumnName = Information.GetPropertyStorageName(
typeof(ApplicationLog),
Information.ExtractPropertyName <ApplicationLog>(a => a.Timestamp));
command.CommandText = $"DELETE FROM {tableName} WHERE {timestampColumnName} <= @timestamp";
SqlParameter timestampParameter = new SqlParameter("@timestamp", SqlDbType.DateTimeOffset)
{
Value = date
};
command.Parameters.Add(timestampParameter);
command.ExecuteScalar();
return(true);
}
finally
{
// Close the connection if that's how we got it.
connection.Close();
}
}
protected void ExecuteSqlQueryButtom_OnClick(object sender, EventArgs e)
{
SQLDataService ds = (SQLDataService)DataServiceProvider.DataService;
IDbConnection connection = ds.GetConnection();
try
{
connection.Open();
var command = connection.CreateCommand();
command.CommandText = "SELECT Город FROM Абитуриент GROUP BY Город ORDER BY COUNT(*) DESC";
var result = command.ExecuteScalar();
}
catch (Exception ex)
{
}
finally
{
connection.Close();
}
}
protected void ExecuteSqlQueryButton_OnClick(object sender, EventArgs e)
{
SQLDataService ds = (SQLDataService)DataServiceProvider.DataService;
IDbConnection connection = ds.GetConnection();
try
{
connection.Open();
var command = connection.CreateCommand();
command.CommandText = "select count(*) from Преподаватель";
var result = command.ExecuteScalar();
QueryResultLabel.Text = result.ToString();
}
catch (Exception ex)
{
QueryResultLabel.Text = ex.ToString();
}
finally
{
connection.Close();
}
}
