Append Data Column
Append Data Column
This Node appends an extra Data Column to the Presence Data Table with the value specified in the input dialog:
Please see the illustration below for an example of how this works:
The resulting table from this operation would contain four columns, with the last one being the one that was appended.
Rather than specify the new value for each row individually, it is common to use functions in combination with Append Columns to create a new column whose value is based on the values of other columns in the row.
In the Append Column dialog there is a dropdown to specify the type of data. The following options are available:
- String - e.g. "Bob"
- Integer - e.g. 26
- Double - e.g. 3.141596
- Date (yyyy-MM-dd) - e.g. 2010-06-17
- Time (HH:mm:ss) - e.g. 17:30:00
- Boolean - e.g. "true" or "false"
- Java Object
This determines how Presence stores the new value internally and can make it easier to use the value in subsequent nodes, for example when inserting into a database with dynamic markers.
This also assists with data validation. If the resolved value of the column cannot be converted to the selected type an error will be thrown, which can be caught by an Error Handler node and dealt with appropriately in your Task.
Multiple Column Appender
This performs the same functionality as the Append Data Column, but allows you to group together several append columns in one node:
This screen is split into two halves - on the left is a list of new columns (this will be blank when first launched). Below this list are the following buttons:
- New Column
- Edit Column Name
- Move Column Up
- Move Column Down
- Clear Column
- Sort Columns Alphabetically
When a new column is created a properties sheet will be visible on the right side of the screen, which is similar to the dialog box presented by the individual Append Column node.
To rename a Column, either double click on the column in the list, or right-click the column and select "Rename Column" from the pop-up menu.
If Rules are set on an append column the value will only be set if the rest of the row conforms to the conditions applied. If the conditions are not met a Null value will be placed instead.
To apply Rules to an individual Append Column Node, right click on the Node in your Task and select Rules > Set Rules from the pop-up menu.
To apply Rules to a new Column in a Multi Column Appender, right click on the item from the left-hand list and select "Rules > Set Rules" from the pop-up menu there.