How to execute SQL statements on a dataset which didn't come from a database?

dataset, delphi, delphi-xe2

Solution

TXQuery (http://code.google.com/p/txquery/) is a component that provides a local SQL engine for executing SQL queries against one or more TDataSets. The only issues I have had with it is updating data via a TDBGrid of a query joining multiple tables (TDataSets) - specifically which table is being updated.

AnyDac v6 (now FireDac) also has a local SQL engine. http://www.da-soft.com/anydac/docu/frames.html?frmname=topic&frmfile=Local_SQL.html

Edit: For the example SQL in your question, because it only involves a single table, you do this with just a Filter on the datatset. For example

ADataSet.Filtered := False;
ADataSet.Filter := 'ZipCode=' + QuotedStr('12345');
ADataSet.Filtered := True;

Problem

Suppose I have an application which fetches a custom XML packet from the server which represents a dataset. Then, suppose I wish to execute a SQL statement on that data via a dataset. What can I use to do this? I don't need to know the code necessarily, but just what to use to make this possible and a general explanation of how. For example, I may fetch a list of customers in XML format from the server. Then, I can use any third-party parser to dump that XML data into some client dataset. Then, execute a query on that dataset, for example `select * from customers where ZipCode = '12345'` without fetching this data from the server again. XML is not the only limitation, that's just an example. I might want to do the same to some application settings loaded from an INI file. Either way, the concept is that the original source of the data is unknown. Whether the dataset stores its temporary data in the memory or on the disk doesn't matter, but it would be excellent if it could keep it in the disk.

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