Pitney Bowes MapXtreme - Manual (Page 154)

Chapter 8: Working with Data
Catalog and Tables
MapXtreme v7.1 161 Developer Guide
Following this chapter are two additional chapters related to data access: Chapter 10: Creating
Expressions , and Chapter 11: Accessing Data from a DBMS .
Catalog and Tables
Catalog is the manager of the MapXtreme data access model. Tables are a fundamental unit of
MapXtreme. Tables hold the data that you want to display and analyze in your application. The
Catalog, as manager, holds a list of tables that are currently open in the session. Tables are also
opened, created and closed from the Catalog.
Nearly all of MapXtreme’s data access operations involve the Catalog and tables.
Tables
The Table class is the basic unit of all data access. Table, Column, and all TAB file metadata
information is accessible from a MapInfo Table. Tables may be mappable (contain a column of type
FeatureGeometry) or non-mappable. Tables also may be open and accessed without displaying a
map.
Table Aliases
When tables are opened, they can be assigned a name (or alias) which is used while the table is
open for referencing the table. For example, the table may be referred to by its alias in SQL
statements. A table that is opened from a TAB file is assigned a default alias if no alias is specified.
The default alias is based upon the name of the TAB file. This property is optional and may be set to
null. However, it is good practice to assign an alias.
Columns
A Column object identifies the properties of a column in a table, feature, or feature collection and
specifies the column's name (alias), data type, width (for string and decimal columns), and other
properties of the column.