6 Copyright © 2009, Oracle. All rights reserved. Using the Data Transformation Operators.

6Copyright © 2009, Oracle. All rights reserved.

Using the Data Transformation Operators

Copyright © 2009, Oracle. All rights reserved.6 - 2

Objectives

After completing this lesson, you should be able to:

• Describe the use of various Mapping Editor operators

• Use operators such as the Joiner, Lookup, Subquery Filter, Sequence, Splitter, and Pivot/Unpivot operators in mappings

• Identify the purpose and important properties of each of the operators


Lesson Agenda

• Overview of the following operators:– Joiner– Lookup– Subquery Filter– Sequence– Set– Splitter– Pivot/Unpivot– Aggregator– Constant– Transformation– Pre/Post Mapping

• Deploying and Executing


Component Palette

This lesson focuses on some of these operators.


Using a Joiner

A joiner is used to extract data from multiple sources and produce a single output row set.

Set the condition in the Join Condition property in the Property Inspector panel. Click the ellipses (…) to start the Expression Builder.


Setting the Join Condition


Setting the Joiner Input Role

T1 T2 Join

Standard Standard T1 Join T2

Standard Outer join T1 LEFT OUTER JOIN T2

Outer Join Standard T1 RIGHT OUTER JOIN T2

Outer Join Outer Join T1 FULL OUTER JOIN T2


Lookup Operator

Use the Lookup operator to look up data from a table, view, cube, or dimension.


Lookup Condition

You have an option of Freestyle Editing. You can write any arbitrary SQL lookup condition in the Lookup

Condition text box.


Handling Multiple Match Rows


Using the Subquery Filter Operator

You can build a subquery quickly and simply.

• By default, the EXISTS condition is used.

• You can change the subquery filter input role to IN, NOT IN, or NOT EXISTS.

Set the condition in the Subquery Filter Condition property in the Property Inspector panel. Click the ellipses (…) to start the Expression Builder.


Sequence Operator

• Generates sequential numbers that increment for each row

• Used to load identifiers that uniquely identifies each record in a table, or each level in a dimension

• Has two output groups:– NEXTVAL – CURRVAL


Set Operation Operator


Using the Splitter Operator for Multitable Insert

Select

Insert

SplitInsert


Quiz

If you have to extract data from multiple sources and produce a single output row set, which operator will you use:

a. Filter

b. Sequence

c. Splitter

d. Joiner


Pivot and Unpivot Operators

Year Q1_SALES Q2_SALES Q3_SALES Q4_SALES

2005 10000 20000 40000 80000

2006 12000 24000 48000 96000

2007 16000 32000 64000 128000

Year Quarter Sales

2005 Q1_SALES 10000

2006 Q1_SALES 12000

2007 Q1_SALES 16000

2005 Q2_SALES 20000

2006 Q3_SALES 48000

……

Pivot transformation operator enables you to transform a single row of attributes into multiple rows. Unpivot performs the reverse.


Wizard-Based Pivot Definition

Click Input Attributes. Note that YEAR is selected as the key column as this remains the same for each

pivoted row.

Click Output Attributes or click Next. Note that QUARTER is selected

as the Row locator column. This is the

pivot column.

Click Pivot transform.

You define how the row is transformed from a row with columns to a

number of rows.


Resulting Pivot Code and Mapping


Aggregator Operator

Performs data aggregations, such as SUM and AVG, and provides an output row set with aggregated data.

You can also define group by and having

clause.


Aggregator Operator

Add new output attributes here and in the Expression field click the ellipses to start the Expression

Builder

From the Function drop down list, select the function. Choose between ALL or DISTINCT. From the drop-down list, select the attribute on which the aggregation should be performed. Click

Use Above Values to get the expression in the text area.


Using a Constant Operator

Constant operator is used to provide constant values to target attributes.


Using the Expression Builder to Definea Constant Operator


Using the Transformation Operator

• Transformations are functions that are used to edit, cleanse, or change your data before it is loaded into the data warehouse.

• OWB currently supports:– SQL standard transformations– User-defined custom transform libraries– Sharing and reusability among modules– Local variables as inputs to a transformation


Transformation Library

User-defined, custom-defined functions or procedures local to the project also appear here.

Also, note Heterogeneous predefined categories of transformations.

• Makes available all applicable database functions

• Includes additional Warehouse Builder predefined functions and procedures

• Categorizes by transformation type for quick access


Transformation Details


Pre/Post Processing Operators

Use Pre/Post Processing operators to perform processing before or after executing a mapping.

Mapping Input Used to provide values into a mapping

Mapping Output Used to send out values from a mapping

Pre-Mapping Calls a procedure or function before executing the mapping

Post-Mapping Calls a procedure or function after executing the mapping


Pre/Post Mapping Operator: Example

Use a Pre-mapping process operator that will invoke a procedure to drop the indexes before the loading starts.

Use a Post-mapping process operator that will invoke a procedure to re-create the indexes after the loading is complete.


Lesson Agenda

• Overview of the following operators:– Joiner– Lookup– Subquery Filter– Sequence– Set– Splitter– Pivot/Unpivot– Aggregator– Constant– Transformation– Pre/Post Mapping

• Deploying and Executing


Deploying Database Objects and Mappings

• Deployment is the process of creating a target system from the logical design or model.

• When you deploy database objects, they get created in the target schema.

• When you deploy a mapping, the scripts or packages are generated (.ddl, .pls and so on).

• When you deploy, you should make sure the objects are deployed in correct sequence.– For example, for a mapping to deploy successfully, the

objects (tables, external tables, sequence, and so on) referenced in the mapping should have been deployed.


Deploying in Projects Navigator Panel

Right-click the object and select Deploy. In the Log panel, view the deployment details. Note that the deploy process involves validation, script generation and finally the creation of the object. In case of mappings, the scripts or packages are generated (.ddl, .pls and so on)


Executing a Mapping


Quiz

If you want to generate the total sales for each product, you will use the following operator in your mapping:

a. Joiner

b. Set

c. Aggregator


Summary

In this lesson, you should have learned how to:

• Describe the use of various transformation operators

• Use operators such as the joiner, lookup, subquery filter, sequence, splitter, and pivot/unpivot operators in mappings

• Identify the purpose and important properties of each of the operators


Practice 6-1 Overview: Using the Joiner, Sequence, and the Transformation Operator in a

Mapping

This practice covers the following topics:

• Creating a Mapping, MAP_GEOGRAPHY, that uses:– A Joiner operator to consolidate data from two staging

tables, Stg_Countries and Stg_Regions. – A Sequence operator to populate a primary key column in

the target– A sysdate Transformation operator to populate the

Load_Date column.


Practice 6-2 Overview: Using the Subquery and the Lookup Operator

This practice covers the following topics:

• Creating a mapping, LOAD_CONTACT, that uses the subquery filter and the Lookup operator. – The scenario: Get all the addresses of customers who have

a high credit limit and are married. You use the Lookup operator to determine the city and the state from the address of customers.

6 Copyright © 2009, Oracle. All rights reserved. Using the Data Transformation Operators.

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