Pitney Bowes MapInfo Professional - Manual (Page 183)

If the Projection button is disabled, the application has read the projection information from the Oracle
metadata and will use that projection to display the file.
Table Bounds
Opens the Set Table Bounds dialog box, which lets you choose the options that determine how your
default view and your entire view table bounds are calculated. The bounds options you specify in this
dialog box define both views. Select one of these options and click OK to implement those bounds
options.
Use Data Bound: By default MapInfo Professional calculates the bounds as the minimum bounding
rectangle of all the data in the layer. This requires scanning the table and calculating this value. This
process can take some time, so a progress bar displays showing you the progress of this operation. You
can cancel it, if necessary.
Use CoordSys Bounds: You can use the coordinate system bounds, but usually we do not recommend
it. The coordinate system bounds are usually much larger than the actual data bounds, which may make
finding your displayed data difficult. You are usually zoomed out too far to be able to locate your data
easily.
Use Custom Bounds: Set your own custom bounds based on the size and location of your data. Click
this option to modify or set the bounds of your data.
About Updating Data Bounds in the MapInfo_MapCatalog
The MapInfo_MapCatalog contains the bounds of the data within the table. This determines the map
view when opening the table as the first map in a window. The bounds are set either by EasyLoader
when loading the data, or from MapInfo Professional's Set Minimum Bounding Rectangle tool.
The bounds automatically adjust when inserting or updating spatial objects. If the object is outside the
Minimum Bounding Rectangle (MBR), MapInfo Professional expands the MBR and updates the
MapInfo_MapCatalog. Deleting objects from the table does not alter the bounds.
Deciding to work with Linked or Live Access Tables
There are two ways in which you can work with your data tables: live (or live with caching) and linked.
If you are not working with very much data, a small data table size, then it does not matter if you choose
to work with live or linked access.
About Live Access Tables
You can access remote data as a live access table using MapInfo Professional. It is called a live access
because there is no local copy of the data, that is, all operations against the data go directly to the server.
This differs from linked tables, which download a snapshot from the remote database into a native
MapInfo Professional table.
You can perform most operations on a live access table that you do for a regular MapInfo Professional
table. For example, you can view, edit, copy, and save a live access layer just as you can a regular
MapInfo Professional table. However, you cannot pack or modify a live access table's structure.
Live with cache is the preferred way to access live tables. MapInfo Professional provides smart caching
to improve performance of live data access from remote databases. During a pan operation, MapInfo
Professional retrieves map data from a cache rather than retrieve it from the server every time. Only
when the pan requires map data not already contained in the cache, does it go to the server. Closing or
refreshing the table clears the cache.
When the live access table is creating a new Map window, the initial view is determined by the entry in
the MapInfo_MapCatalog table. The values in the VIEW_* columns, if they exist, describe a rectangular
183 MapInfo Professional User Guide
Chapter 7: Working with Data in a DBMS