public override MyCatSchemaCollection GetColumns(string[] restrictions)
{
string[] keys = new string[4];
keys[0] = "TABLE_CATALOG";
keys[1] = "TABLE_SCHEMA";
keys[2] = "TABLE_NAME";
keys[3] = "COLUMN_NAME";
MyCatSchemaCollection dt = Query("COLUMNS", null, keys, restrictions);
dt.RemoveColumn("CHARACTER_OCTET_LENGTH");
dt.Name = "Columns";
QuoteDefaultValues(dt);
return(dt);
}