Mapping data using a subquery - 7.2

ELT Greenplum

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Talend Documentation Team
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7.2
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Data Governance > Third-party systems > ELT components > ELT Greenplum components
Data Quality and Preparation > Third-party systems > ELT components > ELT Greenplum components
Design and Development > Third-party systems > ELT components > ELT Greenplum components
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Talend Studio

The sample Job described in this scenario maps the data from two input tables, PreferredSubject and CourseScore, to the output table, TotalScoreOfPreferredSubject, using a subquery.

For more technologies supported by Talend, see Talend components.

Prerequisite

Ensure that you have added an Oracle database connection in the Metadata > Db Connections section prior to creating the Job. For more information, see the Centralizing database metadata section of the Talend Data Integration Studio User Guide.

The Standard Job and the Prejob design

In this scenario, design the Standard Job such as the following:

Design the Prejob that includes the data in this scenario as follows:
The PreferredSubject table contains the student's preferred subject data. To reproduce this scenario, you can load the following data to the Oracle table from a CSV file:
SeqID;StuName;Subject;Detail
1;Amanda;art;Amanda prefers art.
2;Ford;science;Ford prefers science.
3;Kate;art;Kate prefers art.
The CourseScore table contains the student's subject score data. To reproduce this scenario, you can load the following data to the Oracle table from a CSV file:
SeqID;StuName;Subject;Course;Score;Detail
1;Amanda;science;math;85;science score
2;Amanda;science;physics;75;science score
3;Amanda;science;chemistry;80;science score
4;Amanda;art;chinese;85;art score
5;Amanda;art;history;95;art score
6;Amanda;art;geography;80;art score
7;Ford;science;math;95;science score
8;Ford;science;physics;85;science score
9;Ford;science;chemistry;80;science score
10;Ford;art;chinese;75;art score
11;Ford;art;history;80;art score
12;Ford;art;geography;85;art score
13;Kate;science;math;65;science score
14;Kate;science;physics;75;science score
15;Kate;science;chemistry;80;science score
16;Kate;art;chinese;85;art score
17;Kate;art;history;80;art score
18;Kate;art;geography;95;art score
Before the Job execution, the output table TotalScoreOfPreferredSubject does not contain any data:
SeqID;StuName;PreferredSubject;TotalScore