tAddCRCRow - 6.1

Talend Components Reference Guide

EnrichVersion
6.1
EnrichProdName
Talend Big Data
Talend Big Data Platform
Talend Data Fabric
Talend Data Integration
Talend Data Management Platform
Talend Data Services Platform
Talend ESB
Talend MDM Platform
Talend Open Studio for Big Data
Talend Open Studio for Data Integration
Talend Open Studio for Data Quality
Talend Open Studio for ESB
Talend Open Studio for MDM
Talend Real-Time Big Data Platform
task
Data Governance
Data Quality and Preparation
Design and Development
EnrichPlatform
Talend Studio

tAddCRCRow properties

Component family

Data Quality

 

Function

tAddCRCRow calculates a surrogate key based on one or several columns and adds it to the defined schema.

Purpose

Providing a unique ID helps improving the quality of processed data.

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.

In this component, a new CRC column is automatically added.

 

 

Built-in: The schema will be created and stored locally for this component only. 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 designs. Related topic: see Talend Studio User Guide.

 

Implication

Select the check box facing the relevant columns to be used for the surrogate key checksum.

Advanced Settings

CRC type

Select a CRC type in the list. The longer the CRC, the least overlap you will have.

 

tStat Catcher Statistics

Select this check box to collect log data at the component level.

Global Variables

NB_LINE: the number of rows read by an input component or transferred to an output component. This is an After variable and it returns an integer.

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 is an intermediary step. It requires an input flow as well as an output.

Limitation

Due to license incompatibility, one or more JARs required to use this component are not provided. You can install the missing JARs for this particular component by clicking the Install button on the Component tab view. You can also find out and add all missing JARs easily on the Modules tab in the Integration perspective of your studio. For details, see https://help.talend.com/display/KB/How+to+install+external+modules+in+the+Talend+products or the section describing how to configure the Studio in the Talend Installation Guide.

Scenario: Adding a surrogate key to a file

This scenario describes a Job adding a surrogate key to a delimited file schema.

Setting up the Job

  1. Drop the following components: tFileInputDelimited, tAddCRCRow and tLogRow.

  2. Connect them using a Main row connection.

Configuring the input component

  1. In the tFileInputDelimited Component view, set the File Name path and all related properties in case these are not stored in the Repository.

  2. Create the schema through the Edit Schema button, if the schema is not stored already in the Repository. Remember to set the data type column and for more information on the Date pattern to be filled in, visit http://docs.oracle.com/javase/6/docs/api/index.html.

Configuring the tAddCRCRow component

  1. In the tAddCRCRow Component view, select the check boxes of the input flow columns to be used to calculate the CRC.

    Notice that a CRC column (read-only) has been added at the end of the schema.

  2. Select CRC32 as CRC Type to get a longer surrogate key.

  3. In the Basic settings view of tLogRow, select the Print values in cells of a table option to display the output data in a table on the Console.

Job execution

Then save your Job and press F6 to execute it.

An additional CRC Column has been added to the schema calculated on all previously selected columns (in this case all columns of the schema).