public static DataTable GetSchemaTable(string selectSql, IDbAccess dataAccess)
{
if (String.IsNullOrEmpty(selectSql)) return null;
DataTable schemaTable;
Dictionary<string, DataTable> schemaDic = SchemaDic;
if (!schemaDic.TryGetValue(selectSql, out schemaTable))
{
string schemaSql = "SELECT TOP 0 * FROM (" + selectSql + ") T";
schemaTable = dataAccess.QueryDataTable(schemaSql.ToQuery());
schemaDic.Add(selectSql, schemaTable);
}
return schemaTable;
}
