ArcSDE and the Informix Spatial DataBlade
An ArcSDE geodatabase in an Informix database management system (DBMS) stores its spatial data in the Informix Spatial DataBlade data types. Therefore, before ArcSDE can store spatial data in an Informix database, Spatial DataBlade must be registered.
Feature classes in an Informix database
An Informix spatial table can include one or more spatial columns, although ArcSDE restricts a feature class to a single spatial column. Spatial columns are defined with one of Informix Spatial DataBlade's UDTs. A spatial column can only accept data of the type required by the spatial column. For example, an ST_Polygon column rejects integers, characters, and even other types of nonpolygon geometry.
When ArcSDE creates an Informix table with a spatial column, it also creates a row ID column. The row ID is an integer, non-null, unique column that is required by ArcSDE client applications to keep track of selection sets.
ArcSDE adds a record to the geometry_columns table whenever it creates a feature class in an Informix database. Applications using the Informix Spatial DataBlade are responsible for inserting a record into the geometry_columns table each time they add a spatial column to the database.
Guidelines to use existing Informix tables with ArcSDE
Tables with spatial columns can be created by other applications. ArcSDE has been designed to use tables containing spatial columns that were created by other applications or using SQL (sometimes referred to as third-party tables) as long as the tables meet certain prerequisites, including the following:
- It must be owned by the user registering the table.
- It must have an integer, non-null, unique column to use as a row ID column.
- It cannot contain columns of a user-defined type, other than an ST_Geometry column.
- It can contain only one ST_Geometry column.
- It must have only one spatial reference ID for all the records in the table.
To register nonspatial tables, the first three restrictions apply.