Pitney Bowes MapXtreme - Manual (Page 178)

Chapter 8: Working with Data
Table Metadata (TableInfo)
MapXtreme v7.1 185 Developer Guide
Result Sets
ResultSets are similar to view tables in that both are defined using a MapInfo SQL select statement
and have an associated name (Alias). ResultSets, however, have a fixed membership of records
based on the evaluation of the where clause (if any) at the time the result set is created. Any access
to the data in a ResultSet always reflects the data in the source table. However changes to the
source data will not cause the ResultSet to add/remove a record based on the original where clause.
ResultSets manage a set of keys internally.
In general ResultSets are lightweight and temporary. Some of the characteristics of result sets are:
• The data is not copied.
• Access to result sets always accesses its base tables.
• A ResultSet is a sorted list of keys, a collection of column definitions, and a name.
• Membership in the ResultSet is fixed.
• Exception: ResultSets that aggregate, cache the data. Data changed events trigger
recomputation.
• Can be serialized, but not persisted in workspaces.
• ResultSets are vulnerable to Delete and Pack operations.
For more information, see the MapInfo.Data.TableInfoResultSet class in the Developer Reference
Help system.
Source Rows
Source rows represent a match between the table records involved in Table.AddColumns. When
adding temporary columns to a table, multiple records from the data source may be aggregated
together to compute a value for each record in the destination table (also referred to as the bind
table). The MapInfo.Data.SourceRows class is a collection of SourceRows that identify the records
from the data source that were aggregated together,
SourceRows only exist if the BindType property is DynamicCopy, which indicates that changes to
the source data are propagated to the temporaryr column automatically.
L
Table.AddColumns is not supported for the following table types: Server, View, Seamless,
AdoNet, ResultSet, or Drilldown.
See also Adding Expression Columns to a Table .
The GeoDictionary
The GeoDictionary maintains information about which map entities can be matched to which
information. The GeoDictionaries class is a collection of GeoDictionary objects. The
MapInfo.Data.GeoDictionary namespace provides support for data autobinding by being a
programmatic representation of the GeoDictionary file. The GeoDictionary file contains information
about tables (TAB files only). The GeoDictionary is used to automatically determine the table to
which application data should be bound. The GeoDictionary is persisted in a file (typically
GeoDict.DCT) and is maintained using the GeoDictionaryManager utility application (see
Chapter 24: Using the GeoDictionary Manager ).