tSampleRow

tSampleRow properties

Component family	Processing
Function	tSampleRow filters rows according to line numbers.
Purpose	tSampleRow helps to select rows according to a list of single lines and/or a list of groups of lines.
Basic settings	Schema and Edit Schema	A schema is a row description, it defines the number of fields to be processed and passed on to the next component. The schema is either Built-in or stored remotely in the Repository. Since version 5.6, both the Built-In mode and the Repository mode are available in any of the Talend solutions. Click Edit schema to make changes to the schema. If the current schema is of the Repository type, three options are available: View schema: choose this option to view the schema only. Change to built-in property: choose this option to change the schema to Built-in for local changes. Update repository connection: choose this option to change the schema stored in the repository and decide whether to propagate the changes to all the Jobs upon completion. If you just want to propagate the changes to the current Job, you can select No upon completion and choose this schema metadata again in the [Repository Content] window. Click Sync columns to retrieve the schema from the previous component in the Job. This component offers the advantage of the dynamic schema feature. This allows you to retrieve unknown columns from source files or to copy batches of columns from a source without mapping each column individually. For further information about dynamic schemas, see Talend Studio User Guide. This dynamic schema feature is designed for the purpose of retrieving unknown columns of a table and is recommended to be used for this purpose only; it is not recommended for the use of creating tables.
		Built-in: You create the schema and store it locally for the relevant component. Related topic: see Talend Studio User Guide.
		Repository: The schema already exists and is stored in the Repository, hence can be reused in various projects and Job flowcharts. Related topic: see Talend Studio User Guide.
	Range	Enter a range using the relevant syntax to choose a list of single lines and/or a list of groups of lines.
Global Variables	ERROR_MESSAGE: the error message generated by the component when an error occurs. This is an After variable and it returns a string. This variable functions only if the Die on error check box is cleared, if the component has this check box. A Flow variable functions during the execution of a component while an After variable functions after the execution of the component. To fill up a field or expression with a variable, press Ctrl + Space to access the variable list and choose the variable to use from it. For further information about variables, see Talend Studio User Guide.
Usage	This component handles flows of data therefore it requires input and output components.
Log4j	The activity of this component can be logged using the log4j feature. For more information on this feature, see Talend Studio User Guide. For more information on the log4j logging levels, see the Apache documentation at http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html.
Limitation	n/a

Scenario: Filtering rows and groups of rows

This scenario describes a three-component Job. A tRowGenerator is used to create random entries which are directly sent to a
tSampleRow where they will be filtered according to a
defined range. In this scenario, we suppose the input flow contains names of salespersons
along with their respective number of sold products and their years of presence in the
enterprise. The result of the filtering operation is displayed on the Run console.

Dropping and linking the components

Drop the following components from the Palette onto
the design workspace: tRowGenerator, tSampleRow, and tLogRow.
Connect the three components using Row > Main links.

Configuring the components

In the design workspace, select tRowgenerator, and
click the Component tab to define the basic settings
for tRowGenerator.
Click the […] button next to Edit Schema to define the data you want to use as input. In
this scenario, the schema is made of five columns.
In the Basic settings view, click RowGenerator Editor to define the data to be generated.
In the RowGenerator Editor, specify the number of
rows to be generated in the Number of Rows for
RowGenerator field and click OK. The
RowGenerator Editor closes.
In the design workspace, select tSampleRow and
click the Component tab to define the basic settings
for tSampleRow.
In the Basic settings view, set the Schema to Built-In and click
Sync columns to retrieve the schema from the
tRowGenerator component.
In the Range panel, set the filter to select your
rows using the correct syntax as explained. In this scenario, we want to select the
first and fifth lines along with the group of lines between 9 and 12.
In the design workspace, select tLogRow and click
the Component tab to define its basic settings. For
more information about tLogRow, see tLogRow.

Saving and execting the Job

Press Ctrl+S to save your Job.
Press F6, or click Run on the Run tab to execute the
Job.

The filtering result displayed on the console shows the first and fifth rows and the
group of rows between 9 and 12.

Document get from Talend https://help.talend.com

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Docs 5.x

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tSampleRow – Docs for ESB 5.x