Assumptions
The following is assumed:
- You know how to create a trigger and add actions to that trigger using the Canvas Editor. For more information on the Canvas Editor, see Using the Canvas Editor.
- You are familiar with Structured Query Language (SQL) and relational databases.
Retrieving data from a local database table using Local DB Select
This example describes a trigger that when executed
retrieves rows from a local database table using the
Local DB Select action. The following
shows a portion of the sample trigger:
The sample trigger has a Local DB Select action and Log Message action.
Using the Local DB Select action, each
column can be mapped to a variable (including trigger
variables and device variables).
In order to process the data retrieved, the Local
DB Select action must iterate through the rows
returned by the SQL Select operation. You can process the
column values for each row using the Next
Row option on the Local DB Select
action Routing tab. The last action on the
Next Row route must be routed to the
Local DB Select action.
For this example, there is only one action to execute from
the Next Row route. The Log
Message action Success route is
returning to the Local DB Select
action.
When there are no more rows to process and no errors
encountered, the logic flow from the Local DB
Select action will follow the
Success route. The number of times the
Next Row route will be executed is given
by the values returned in Rows Selected.
The Row Index keeps track of the current
row being processed.