The Data Access Manager (DAM) was a database access API for the classic Mac OS, introduced in 1991 as an extension to System 7. Similar in concept to ODBC, DAM saw little use and was eventually dropped in the late 1990s. Only a handful of products ever used it, although it was used for some extremely impressive demoware in the early 1990s. More modern versions of the classic Mac OS, and macOS, use ODBC for this role instead. Concepts DAM and ODBC are similar in many ways. The primary purpose of both systems was to send "query strings" to a data provider, who would respond (potentially) with a "result set" consisting of rows of data. Both systems were expected to convert data to and from the system's respective formats, integers and strings for instance. Additionally, both provided a communications subsystem that hid the details of sending queries and data between the client and server. Like most Apple software, DAM attempted to make the query process as simple as possible for the users, both application users and programmers writing those applications. One particularly notable feature was the concept of "query documents". Query documents contained any number of pre-defined queries (or other server commands), along with optional code to modify them before being sent to the server. For instance, a typical query document might contain a query string that would log into the database server, and if that was successful, look up the current date from the local client machine using a Mac OS call, and then use that date in a query that returns inventory in a warehouse for a given date. Query documents could also include computer code and resources needed to support this process, for instance, a dialog box asking for the username and password. Applications could use query documents without having any idea of the internals of the query. They simply opened the document, which consisted of a series of resources, and ran each query resource inside in turn. The DAM would ensure that any needed code in the document would be run without the application even being aware of it, and eventually, results would be passed back to the application for display. The entire operation was opaque, allowing applications to add DAM support with ease. DAM also included two more direct API's, the High Level interface, and the Low Level interface. High Level was fairly similar to