Data Access and Transactions

Client Cursor Engine

Remote Data Service calls Cursor Service (invisible to the user) to perform tasks for you automatically. It caches, in memory (or temporarily on disk, for large sets of data), the set of query results retrieved from a data source, as well as client updates to those results. It also contains layout information about the data such as table layouts, row counts, primary and secondary keys, column names, and timestamps, as well as the actual table data itself. To manage the cache, Cursor Service can:

Create and delete temporary tables.
Populate tables.
Manage updates to the data values.
Provide schema information (such as base tables, key columns, read-write columns, and computed columns).
Provide the mechanism to send updates as a batch to the server, with minimum network traffic, by sending only the modified records.

For more information about the differences between the client-side and server-side cursor engines, see Recordsets and Cursors.