aRTtable {aRT} | R Documentation |
Class aRTtable
Description
Class that represents a DBMS table. It can be one of the various TerraLib
table types.
Tables are created from layers or directly from the database. When it is created from a layer,
ther attributes are be linked to the geometries of that layer. When it is created from a database,
it does not have any geometry associated. For selecting data joining tables with the links use aRTthemes
.
Objects from the Class
Objects can be created by calling openTable()
or createTable()
, from aRTlayer
of form aRTdb
.
Extends
Class aRTcomponent
, directly.
Methods
- addRows:
- Adds rows to the table.
- createColumn:
- Creates a column in the table.
- createAndFillColumn:
- Creates a column based on some operation of another layer.
It works only with tables of cellular layers.
- createRelation:
- Creates a relation between an attribute of the table and an attribute of another table.
- getData:
- Returns the table values.
- updateColumns:
- Adds columns and(or) update them.
Table types
In TerraLib there are several types of table, implementing the entity relationship,
temporal and other models. They are:
- static
- Table which each geomety has one, and only one, respective row.
- media
- A media table has only two columns: object_id and media_name.
It associates an url to a geometry double-click in a TerraLib-based GIS.
A layer can have only one media table, and this table does not have a name.
- external
- Each row is not implicitly connected to a geometry, but
the table can have foreign keys to all static, event and dynamoc tables.
- event
- One geometry occours in a specific time interval, as murderers.
- dynatt
- Attributes changing in the time, but the objects have static geometry.
- alldyn
- Fully dynamic (attributes and geometry). (not implemented yet)
- dyngeom
- Dynamic Geometry. (not implemented yet)
- default
- The default value depending on the parent. If the class is aRTlayer,
default will be static, else (aRTdb) it will be external.
Author(s)
Pedro Ribeiro de Andrade
See Also
See aRTtable-METHOD
for a method of this class or CLASSNAME-class
for links to other classes.
[Package
aRT version 1.6-4
Index]