private static DataTable DescribeColumns(ClickHouseConnection connection, string[] restrictions)
{
var query = new StringBuilder("SELECT database as Database, table as Table, name as Name, type as ProviderType, type as DataType FROM system.columns");
var database = restrictions != null && restrictions.Length > 0 ? restrictions[0] : null;
var table = restrictions != null && restrictions.Length > 1 ? restrictions[1] : null;
if (database != null)
{
query.Append($" WHERE database='{database}'");
}
if (table != null)
{
query.Append($" AND table='{table}'");
}
var result = connection.ExecuteDataTable(query.ToString());
foreach (var row in result.Rows.Cast <DataRow>())
{
var clickHouseType = TypeConverter.ParseClickHouseType((string)row["ProviderType"]);
row["ProviderType"] = clickHouseType.ToString();
// TODO: this should return actual framework type like other implementations do
row["DataType"] = clickHouseType.FrameworkType.ToString().Replace("System.", string.Empty);
}
return(result);
}
