If you are looking to integrate Sage with other packages within your business then perhaps I can help. All products in the range have the ability to take into and out of the accounting system to make integration very viable. The mid range Sage 200 solution and the high-end Sage 1000 solution both make use of Microsoft SQL Server (MSSQL) which can facilitate the movement of data in and out providing you know which tables store which data! So the options for each product are;

Sage (Line) 50
Line 50 actually ships with a read-only ODBC driver. So you can use this driver to export data from Sage 50 into, for example, Excel or into a third party/bespoke application.

If you need to get data into Line 50 then you can either use one of the import routines in the product which are good for static data such as customers and suppliers but a bit limited with transactional data. Additionally the Sage 50 SDK allows the writing of data into the database and takes care of updating the required tables. The actual format of the data is not known for sure but I believe it to be some old btrieve type file storage system. Using the ODBC driver with an SQL query tool is ok for basic queries but it soon struggles with multi-table joins.

Sage 200 (and Sage 200 Suite which is financials plus CRM)
Sage 200 uses MSSQL so it is easy to extract data. However there are alot of tables and it can be abit fo a struggle without the data model. Sage do produce a data model definition document but this is only available to registered Sage developers.

Again for importing data it is either a case of using the inbuilt import routines, inserting records directly into the tables (unsupported by Sage and dangerous unless you really know what you are doing) or using the SDK.

Sage Line 500/Sage 1000
Sage 1000 does have an API which is quite limited for getting data into the system. There is an old routine called tetralink which also allows basic data import and there is a 3rd party tool with templates which allows certain data to be uploaded via Excel.

The data model in Sage 1000 is huge and the legacy of the data model is that it used to be an old btrieve flat file system and today even though it resides within MSSQL there is no referential integrity, primary or foreign keys defined in the data. Add to that there are 1800+ tables all 8-10 characters in length (hardly descriptive!) and no documentation.

If you are looking to get data in or out of any of the above systems I can help. I already have export routines for Line 50, the documentation for the Sage 200 model and years of experience of working with the Sage Line 500/Sage 1000 data model. You can contact me here.