Use the following information to decide whether to work with your remote data tables live or linked.
| Linked Table | Live Table | |
|---|---|---|
|
Definition |
A full replica of the DBMS table is downloaded to the client machine. The local replica retains reference to the remote data source (ODBC/OCI Connection parameters); The downloaded copy is retained across sessions of MapInfo Pro. |
Data is read from the DBMS Server as required. When the data is locally cached, the life of the cache is limited to the current session. |
|
Suitability |
Linked tables are suitable for backdrop display data, or data that does not change much. Linked tables are editable, as long as the base tables they are based on are editable. |
Live tables are suitable for reading and editing dynamically changing data; or data sets that do not fit within the limits of 2 GB per data file. Live tables are recommended if you want to maintain data security (the data must remain only in a single secure location). |
|
Performance Factors |
As the data is entirely local, there is a one-time cost of downloading the data, but subsequent access is fast, comparable to native table access, since the user does not incur the cost of network traffic every time the data needs to be accessed for mapping, or for analysis. |
The cost of data transfer is incurred a little bit at a time. Live tables are accessed real time from the database, as required. Optionally, records from the live table can be locally cached for the length of the MapInfo Pro session. Caching enhances performance, because the data is not fetched multiple times as the user, zooms, pans, or browses around the data. |
|
Limitations |
Linked tables are limited to 2 GB per data file; Linked tables are not refreshed unless the user explicitly refreshes the table. You cannot pack a linked table. You cannot modify the table structure of a linked table.For details, see File Size Exceeds 2 GB. |
This is a network intensive option. |
For more information, see Improving Live Access Performance.