Specific attribute types
Here is a brief overview of complex attribute types. These attribute types are common for various groups of components.
Links to corresponding sections follow:
When you need to specify a file in a component, you need to use URL File Dialog.
Some components use a specific metadata structure on their ports. The connected edges can be easily assigned metadata from predefined templates. See metadata templates.
Some components can be configured with a time interval (usually a delay or a timeout). For an overview of the syntax of time interval specification, see Time Intervals.
In some of the components, records must be grouped according to values of a group key. In this key, neither the order of key fields nor the sort order are of importance. See Group Key.
In some of the components, records must be grouped and sorted according to the values of a sort key. In this key, both the order of key fields and the sort order are of importance. See Sort Key.
In many components from different groups of components, a transformation can be or must be defined. See Defining Transformations.
Time Intervals
The following time units may be used when specifying time intervals:
w
week (7 days)
d
day (24 hours)
h
hour (60 minutes)
m
minute (60 seconds)
s
second (1000 milliseconds)
ms
millisecond
The units may be arbitrarily combined, but their order must be from the largest to the smallest one.
Example 3. Time Interval Specification
1w 2d 5h 30m 5s 100ms = 797405100 milliseconds
1h 30m = 5400000 milliseconds
120s = 120000 milliseconds
When no time unit is specified, the number is assumed to denote the default unit, which is component-specific (usually milliseconds).
See also: HTTPConnector, WebServiceClient.
Group Key
Sometimes you need to select fields that will create a grouping key. This can be done in the Edit key dialog. After opening the dialog, you need to select the fields that should create the group key.
Select the fields you want and drag and drop each of the selected key fields to the Key parts pane on the right. (You can also use the Arrow buttons.)
After selecting the fields, you can click the OK button and the selected field names will turn to a sequence of the same field names separated by a semicolon. This sequence can be seen in the corresponding attribute row.
The resulting group key is a sequence of field names separated by a semicolon. It looks like this: FieldM;…​FieldN.
In this kind of key, no sort order is shown unlike in Sort key. By default, the order is ascending for all fields and priority of these fields descends down from top in the dialog pane and to the right from the left in the attribute row. For more detailed information, see Sort Key.
When a key is defined and used in a component, input records are gathered together into a group of the records with equal key values.
Ordering Type
The key is ordered in following ways:
Ascending - if the input records are sorted in ascending order
Descending - if the input records are sorted in descending order
Auto - the sorting order of the input records is guessed from the first two records with different value in the key field, i.e., from the first records of the first two groups.
Ignore - if the input records with the same key field value(s) are not sorted
Group key is used in the following components:
Group key in SortWithinGroups
Merge key in Merge
Aggregate key in Aggregate
Key in Denormalizer
Group key in Rollup
Sort Key
In some of the components you need to define a sort key. Like a group key, this sort key can also be defined by selecting key fields using the Edit key dialog. There you can also choose what sort order should be used for each of the selected fields.
In the Edit key dialog, select the fields you want and drag and drop each of the selected key fields to the Key column of the Key parts pane on the right. (You can also use the Arrow buttons.)
Unlike in the case of a group key, in any sort key the order in which the fields are selected is of importance.
In every sort key, the field at the top has the highest sorting priority. Then the sorting priority descends down from top. The field at the bottom has the lowest sorting priority.
When you click the OK button, the selected fields will turn to a sequence of the same field names and an a or d letter in parentheses (with the meaning: ascending or descending, respectively) separated by a semicolon.
It can look like this: FieldM(a);…​FieldN(d).
This sequence can be seen in the corresponding attribute row. (The highest sorting priority has the first field in the sequence. The priority descends towards the end of the sequence.)
As you can see, in this kind of key, the sort order is expressed separately for each key field (either Ascending or Descending). The default sort order is Ascending. The default sort order can also be changed in the Order column of the Key parts pane.
Example 4. Sorting
If your sort key is the following: Salary(d);LastName(a);FirstName(a). The records will be sorted according to the Salary values in descending order, then the records will be sorted according to LastName within the same Salary value and they will be sorted according to FirstName within the same LastName and the same Salary (both in ascending order) value.
Thus, any person with Salary of 25000 will be processed after any other person with a salary of 28000. And, within the same Salary, any Brown will be processed before any Smith. And again, within the same salary, any John Smith will be processed before any Peter Smith. The highest priority is Salary, the lowest is FirstName.
Sort key is used in the following cases:
Sort key in ExtSort
Sort key in FastSort
Sort key in SortWithinGroups
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