TRANSFORMATIONS PART-1 IN INFORMATICA

FILTER TRANSFORMATION

• Active and connected transformation.

We can filter rows in a mapping with the Filter transformation. We pass all the rows from a source transformation through the Filter transformation, and then enter a Filter condition for the transformation. All ports in a Filter transformation are input/output and only rows that meet the condition pass through the Filter Transformation.

Example: to filter records where SAL>2000

• Import the source table EMP in Shared folder. If it is already there, then don’t Import.
• In shared folder, create the target table Filter_Example. Keep all fields as in EMP table.
• Create the necessary shortcuts in the folder.

Creating Mapping:

1. Open folder where we want to create the mapping.
2. Click Tools -> Mapping Designer.
3. Click Mapping -> Create -> Give mapping name. Ex: m_filter_example
4. Drag EMP from source in mapping.
5. Click Transformation -> Create -> Select Filter from list. Give name and click  Create. Now click done.
6. Pass ports from SQ_EMP to Filter Transformation.
7. Edit Filter Transformation. Go to Properties Tab
8. Click the Value section of the Filter condition, and then click the Open button.
9. The Expression Editor appears.
10. Enter the filter condition you want to apply.
11. Click Validate to check the syntax of the conditions you entered.
12. Click OK -> Click Apply -> Click Ok.
13. Now connect the ports from Filter to target table.
14. Click Mapping -> Validate
15. Repository -> Save

Create Session and Workflow as described earlier. Run the workflow and see the data in target table.
How to filter out rows with null values?
To filter out rows containing null values or spaces, use the ISNULL and IS_SPACES Functions to test the value of the port. For example, if we want to filter out rows that  Contain NULLs in the FIRST_NAME port, use the following condition:
IIF (ISNULL (FIRST_NAME), FALSE, TRUE)
This condition states that if the FIRST_NAME port is NULL, the return value is FALSE and the row should be discarded. Otherwise, the row passes through to the next Transformation.
Performance tuning:
Filter transformation is used to filter off unwanted fields based on conditions we Specify.

1. Use filter transformation as close to source as possible so that unwanted data gets Eliminated sooner.
2. If elimination of unwanted data can be done by source qualifier instead of filter,Then eliminate them at Source Qualifier itself.
3. Use conditional filters and keep the filter condition simple, involving TRUE/FALSE or 1/0 

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Expression TRANSFORMATION:

• Passive and connected transformation.

Use the Expression transformation to calculate values in a single row before we write to the target. For example, we might need to adjust employee salaries, concatenate first and last names, or convert strings to numbers.
Use the Expression transformation to perform any non-aggregate calculations.
Example: Addition, Subtraction, Multiplication, Division, Concat, Uppercase conversion, lowercase conversion etc.
We can also use the Expression transformation to test conditional statements before we output the results to target tables or other transformations. Example: IF, Then, Decode
There are 3 types of ports in Expression Transformation:

• Input
• Output
• Variable: Used to store any temporary calculation.

Calculating Values :
To use the Expression transformation to calculate values for a single row, we must include the following ports:

• Input or input/output ports for each value used in the calculation: For example: To calculate Total Salary, we need salary and commission.
•  Output port for the expression: We enter one expression for each output port. The return value for the output port needs to match the return value of the expression.

We can enter multiple expressions in a single Expression transformation. We can create any number of output ports in the transformation.
Example: Calculating Total Salary of an Employee

• Import the source table EMP in Shared folder. If it is already there, then don’t  import.
• In shared folder, create the target table Emp_Total_SAL. Keep all ports as in EMP table except Sal and Comm in target table. Add Total_SAL port to store the calculation.
• Create the necessary shortcuts in the folder.

Creating Mapping:

1. Open folder where we want to create the mapping.
2. Click Tools -> Mapping Designer.
3. Click Mapping -> Create -> Give mapping name. Ex: m_totalsal
4. Drag EMP from source in mapping.
5. Click Transformation -> Create -> Select Expression from list. Give name and click Create. Now click done.
6. Link ports from SQ_EMP to Expression Transformation.
7. Edit Expression Transformation. As we do not want Sal and Comm in target, remove check from output port for both columns.
8. Now create a new port out_Total_SAL. Make it as output port only.
9. Click the small button that appears in the Expression section of the dialog box and enter the expression in the Expression Editor.
10. Enter expression SAL + COMM. You can select SAL and COMM from Ports tab in expression editor.
11. Check the expression syntax by clicking Validate.
12. Click OK -> Click Apply -> Click Ok.
13. Now connect the ports from Expression to target table.
14. Click Mapping -> Validate
15. Repository -> Save

Create Session and Workflow as described earlier. Run the workflow and see the data in target table.

As COMM is null, Total_SAL will be null in most cases. Now open your mapping and expression transformation. Select COMM port, In Default Value give 0. Now apply changes. Validate Mapping and Save.
Refresh the session and validate workflow again. Run the workflow and see the result again.
Now use ERROR in Default value of COMM to skip rows where COMM is null.
Syntax: ERROR(‘Any message here’)
Similarly, we can use ABORT function to abort the session if COMM is null.
Syntax: ABORT(‘Any message here’)
Make sure to double click the session after doing any changes in mapping. It will prompt that mapping has changed. Click OK to refresh the mapping. Run workflow after validating and saving the workflow.
Performance tuning :
Expression transformation is used to perform simple calculations and also to do Source lookups.

1. Use operators instead of functions.
2. Minimize the usage of string functions.
3. If we use a complex expression multiple times in the expression transformer, then Make that expression as a variable. Then we need to use only this variable for all computations.

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Router Transformation :

• Active and connected transformation.

A Router transformation is similar to a Filter transformation because both transformations allow you to use a condition to test data. A Filter transformation tests data for one condition and drops the rows of data that do not meet the Condition. However, a Router transformation tests data for one or more conditions And gives you the option to route rows of data that do not meet any of the conditions to a default output group.
Example: If we want to keep employees of France, India, US in 3 different tables, then we can use 3 Filter transformations or 1 Router transformation.

Mapping A uses three Filter transformations while Mapping B produces the same result with one Router transformation.
A Router transformation consists of input and output groups, input and output ports, group filter conditions, and properties that we configure in the Designer.


Working with Groups
A Router transformation has the following types of groups:

• Input: The Group that gets the input ports.
• Output: User Defined Groups and Default Group. We cannot modify or delete Output ports or their properties.

User-Defined Groups: We create a user-defined group to test a condition based on incoming data. A user-defined group consists of output ports and a group filter Condition. We can create and edit user-defined groups on the Groups tab with the Designer. Create one user-defined group for each condition that we want to specify.
The Default Group: The Designer creates the default group after we create one new user-defined group. The Designer does not allow us to edit or delete the default group. This group does not have a group filter condition associated with it. If all of the conditions evaluate to FALSE, the IS passes the row to the default group.
Example: Filtering employees of Department 10 to EMP_10, Department 20 to EMP_20 and rest to EMP_REST

• Source is EMP Table.
• Create 3 target tables EMP_10, EMP_20 and EMP_REST in shared folder. Structure should be same as EMP table.
• Create the shortcuts in your folder.

Creating Mapping:
1. Open folder where we want to create the mapping.
2. Click Tools -> Mapping Designer.
3. Click Mapping-> Create-> Give mapping name. Ex: m_router_example
4. Drag EMP from source in mapping.
5. Click Transformation -> Create -> Select Router from list. Give name and
Click Create. Now click done.
6. Pass ports from SQ_EMP to Router Transformation.
7. Edit Router Transformation. Go to Groups Tab
8. Click the Groups tab, and then click the Add button to create a user-defined Group. The default group is created automatically..
9. Click the Group Filter Condition field to open the Expression Editor.
10. Enter a group filter condition. Ex: DEPTNO=10
11. Click Validate to check the syntax of the conditions you entered.

12. Create another group for EMP_20. Condition: DEPTNO=20
13. The rest of the records not matching the above two conditions will be passed to DEFAULT group. See sample mapping
14. Click OK -> Click Apply -> Click Ok.
15. Now connect the ports from router to target tables.
16. Click Mapping -> Validate
17. Repository -> Save

• Create Session and Workflow as described earlier. Run the Workflow and see the data in target table.
• Make sure to give connection information for all 3 target tables.

Sample Mapping:

Difference between Router and Filter :
We cannot pass rejected data forward in filter but we can pass it in router. Rejected data is in Default Group of router.

 

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SORTER TRANSFORMATION

• Connected and Active Transformation
• The Sorter transformation allows us to sort data.
• We can sort data in ascending or descending order according to a specified sort key.
• We can also configure the Sorter transformation for case-sensitive sorting, and specify whether the output rows should be distinct.

When we create a Sorter transformation in a mapping, we specify one or more ports as a sort key and configure each sort key port to sort in ascending or descending order. We also configure sort criteria the Power Center Server applies to all sort key ports and the system resources it allocates to perform the sort operation.
The Sorter transformation contains only input/output ports. All data passing through the Sorter transformation is sorted according to a sort key. The sort key is one or more ports that we want to use as the sort criteria.
Sorter Transformation Properties
1. Sorter Cache Size:
The Power Center Server uses the Sorter Cache Size property to determine the maximum amount of memory it can allocate to perform the sort operation. The Power Center Server passes all incoming data into the Sorter transformation Before it performs the sort operation.

• We can specify any amount between 1 MB and 4 GB for the Sorter cache size.
• If it cannot allocate enough memory, the Power Center Server fails the Session.
• For best performance, configure Sorter cache size with a value less than or equal to the amount of available physical RAM on the Power Center Server machine.
• Informatica recommends allocating at least 8 MB of physical memory to sort data using the Sorter transformation.

2. Case Sensitive:
The Case Sensitive property determines whether the Power Center Server considers case when sorting data. When we enable the Case Sensitive property, the Power Center Server sorts uppercase characters higher than lowercase characters.
3. Work Directory
Directory Power Center Server uses to create temporary files while it sorts data.
4. Distinct:
Check this option if we want to remove duplicates. Sorter will sort data according to all the ports when it is selected.

Example: Sorting data of EMP by ENAME

• Source is EMP table.
• Create a target table EMP_SORTER_EXAMPLE in target designer. Structure same as EMP table.
• Create the shortcuts in your folder.

Creating Mapping:
1. Open folder where we want to create the mapping.
2. Click Tools -> Mapping Designer.
3. Click Mapping-> Create-> Give mapping name. Ex: m_sorter_example
4. Drag EMP from source in mapping.
5. Click Transformation -> Create -> Select Sorter from list. Give name and click Create. Now click done.
6. Pass ports from SQ_EMP to Sorter Transformation.
7. Edit Sorter Transformation. Go to Ports Tab
8. Select ENAME as sort key. CHECK mark on KEY in front of ENAME.
9. Click Properties Tab and Select Properties as needed.
10. Click Apply -> Ok.
11. Drag target table now.
12. Connect the output ports from Sorter to target table.
13. Click Mapping -> Validate
14. Repository -> Save

• Create Session and Workflow as described earlier. Run the Workflow and see the data in target table.
• Make sure to give connection information for all tables.

Sample Sorter Mapping :

Performance Tuning:
Sorter transformation is used to sort the input data.

1. While using the sorter transformation, configure sorter cache size to be larger than the input data size.
2. Configure the sorter cache size setting to be larger than the input data size while Using sorter transformation.
3. At the sorter transformation, use hash auto keys partitioning or hash user keys Partitioning.

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RANK TRANSFORMATION:

• Active and connected transformation

The Rank transformation allows us to select only the top or bottom rank of data. It Allows us to select a group of top or bottom values, not just one value.
During the session, the Power Center Server caches input data until it can perform The rank calculations.
Rank Transformation Properties :

• Cache Directory where cache will be made.
• Top/Bottom Rank as per need
• Number of Ranks Ex: 1, 2 or any number
• Case Sensitive Comparison can be checked if needed
• Rank Data Cache Size can be set
• Rank Index Cache Size can be set

Ports in a Rank Transformation :

Ports	Number Required	Description
I	1 Minimum	Port to receive data from another transformation.
O	1 Minimum	Port we want to pass to other transformation.
V	not needed	can use to store values or calculations to use in an expression.
R	Only 1	Rank port. Rank is calculated according to it. The Rank port is an input/output port. We must link the Rank port to another transformation. Example: Total Salary

Rank Index
The Designer automatically creates a RANKINDEX port for each Rank transformation. The Power Center Server uses the Rank Index port to store the ranking position for Each row in a group.
For example, if we create a Rank transformation that ranks the top five salaried employees, the rank index numbers the employees from 1 to 5.

• The RANKINDEX is an output port only.
• We can pass the rank index to another transformation in the mapping or directly to a target.
• We cannot delete or edit it.

Defining Groups
Rank transformation allows us to group information. For example: If we want to select the top 3 salaried employees of each Department, we can define a group for Department.

• By defining groups, we create one set of ranked rows for each group.
• We define a group in Ports tab. Click the Group By for needed port.
• We cannot Group By on port which is also Rank Port.

1) Example: Finding Top 5 Salaried Employees

• EMP will be source table.
• Create a target table EMP_RANK_EXAMPLE in target designer. Structure should be same as EMP table. Just add one more port Rank_Index to store RANK INDEX.
• Create the shortcuts in your folder.

Creating Mapping:

1. Open folder where we want to create the mapping.
2. Click Tools -> Mapping Designer.
3. Click Mapping-> Create-> Give mapping name. Ex: m_rank_example
4. Drag EMP from source in mapping.
5. Create an EXPRESSION transformation to calculate TOTAL_SAL.
6. Click Transformation -> Create -> Select RANK from list. Give name and click Create. Now click done.
7. Pass ports from Expression to Rank Transformation.
8. Edit Rank Transformation. Go to Ports Tab
9. Select TOTAL_SAL as rank port. Check R type in front of TOTAL_SAL.
10. Click Properties Tab and Select Properties as needed.
11. Top in Top/Bottom and Number of Ranks as 5.
12. Click Apply -> Ok.
13. Drag target table now.
14. Connect the output ports from Rank to target table.
15. Click Mapping -> Validate
16. Repository -> Save

• Create Session and Workflow as described earlier. Run the Workflow and see the data in target table.
• Make sure to give connection information for all tables.

2) Example: Finding Top 2 Salaried Employees for every DEPARTMENT

• Open the mapping made above. Edit Rank Transformation.
• Go to Ports Tab. Select Group By for DEPTNO.
• Go to Properties tab. Set Number of Ranks as 2.
• Click Apply -> Ok.
• Mapping -> Validate and Repository Save.

Refresh the session by double clicking. Save the changed and run workflow to see the new result.

RANK CACHE
Sample Rank Mapping
When the Power Center Server runs a session with a Rank transformation, it compares an input row with rows in the data cache. If the input row out-ranks a Stored row, the Power Center Server replaces the stored row with the input row.
Example: Power Center caches the first 5 rows if we are finding top 5 salaried Employees. When 6^th row is read, it compares it with 5 rows in cache and places it in Cache is needed.
1) RANK INDEX CACHE:
The index cache holds group information from the group by ports. If we are Using Group By on DEPTNO, then this cache stores values 10, 20, 30 etc.

• All Group By Columns are in RANK INDEX CACHE. Ex. DEPTNO

2) RANK DATA CACHE:
It holds row data until the Power Center Server completes the ranking and is Generally larger than the index cache. To reduce the data cache size, connect Only the necessary input/output ports to subsequent transformations.

• All Variable ports if there, Rank Port, All ports going out from RANK Transformations are stored in RANK DATA CACHE.
• Example: All ports except DEPTNO In our mapping example.

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TRANSACTION CONTROL TRANSFORMATION:

Power Center lets you control commit and roll back transactions based on a set of rows that pass through a Transaction Control transformation. A transaction is the set of rows bound by commit or roll back rows. You can define a transaction based on a varying number of input rows. You might want to define transactions based on a group of rows ordered on a common key, such as employee ID or order entry date.
In Power Center, you define transaction control at the following levels:

• Within a mapping. Within a mapping, you use the Transaction Control transformation to define a transaction. You define transactions using an expression in a Transaction Control transformation. Based on the return value of the expression, you can choose to commit, roll back, or continue without any transaction changes.
• Within a session. When you configure a session, you configure it for user-defined commit. You can choose to commit or roll back a transaction if the Integration Service fails to transform or write any row to the target.

When you run the session, the Integration Service evaluates the expression for each row that enters the transformation. When it evaluates a commit row, it commits all rows in the transaction to the target or targets. When the Integration Service evaluates a roll back row, it rolls back all rows in the transaction from the target or targets. If the mapping has a flat file target you can generate an output file each time the Integration Service starts a new transaction. You can dynamically name each target flat file.
Properties Tab
On the Properties tab, you can configure the following properties:

• Transaction control expression
• Tracing level

Enter the transaction control expression in the Transaction Control Condition field. The transaction control expression uses the IIF function to test each row against the condition. Use the following syntax for the expression:
IIF (condition, value1, value2)
The expression contains values that represent actions the Integration Service performs based on the return value of the condition. The Integration Service evaluates the condition on a row-by-row basis. The return value determines whether the Integration Service commits, rolls back, or makes no transaction changes to the row.
When the Integration Service issues a commit or roll back based on the return value of the expression, it begins a new transaction. Use the following built-in variables in the Expression Editor when you create a transaction control expression:

• TC_CONTINUE_TRANSACTION. The Integration Service does not perform any transaction change for this row. This is the default value of the expression.
• TC_COMMIT_BEFORE. The Integration Service commits the transaction, begins a new transaction, and writes the current row to the target. The current row is in the new transaction.
• TC_COMMIT_AFTER. The Integration Service writes the current row to the target, commits the transaction, and begins a new transaction. The current row is in the committed transaction.
• TC_ROLLBACK_BEFORE. The Integration Service rolls back the current transaction, begins a new transaction, and writes the current row to the target. The current row is in the new transaction.
• TC_ROLLBACK_AFTER. The Integration Service writes the current row to the target, rolls back the transaction, and begins a new transaction. The current row is in the rolled back transaction.

If the transaction control expression evaluates to a value other than commit, roll back, or continue, the Integration Service fails the session.
Mapping Guidelines and Validation
Use the following rules and guidelines when you create a mapping with a Transaction Control transformation:

• If the mapping includes an XML target, and you choose to append or create a new document on commit, the input groups must receive data from the same transaction control point.
• Transaction Control transformations connected to any target other than relational, XML, or dynamic MQSeries targets are ineffective for those targets.
• You must connect each target instance to a Transaction Control transformation.
• You can connect multiple targets to a single Transaction Control transformation.
• You can connect only one effective Transaction Control transformation to a target.
• You cannot place a Transaction Control transformation in a pipeline branch that starts with a Sequence Generator transformation.
• If you use a dynamic Lookup transformation and a Transaction Control transformation in the same mapping, a rolled-back transaction might result in unsynchronized target data.
• A Transaction Control transformation may be effective for one target and ineffective for another target. If each target is connected to an effective Transaction Control transformation, the mapping is valid.
• Either all targets or none of the targets in the mapping should be connected to an effective Transaction Control transformation.

Example to Transaction Control:
Step 1: Design the mapping.

Step 2: Creating a Transaction Control Transformation.

• In the Mapping Designer, click Transformation > Create. Select the Transaction Control transformation.
• Enter a name for the transformation.[ The naming convention for Transaction Control transformations is TC_TransformationName].
• Enter a description for the transformation.
• Click Create.
• Click Done.
• Drag the ports into the transformation.
• Open the Edit Transformations dialog box, and select the Ports tab.

Select the Properties tab. Enter the transaction control expression that defines the commit and roll back behavior.

Go to the Properties tab and click on the down arrow to get in to the expression editor window. Later go to the Variables tab and Type IIF(EMpno=7654,) select the below things from the built in functions.
IIF (EMPNO=7654,TC_COMMIT_BEFORE,TC_CONTINUE_TRANSACTION)

• Connect all the columns from the transformation to the target table and save the mapping.
• Select the Metadata Extensions tab. Create or edit metadata extensions for the Transaction Control transformation.
• Click OK.

Step 3: Create the task and the work flow.
Step 4: Preview the output in the target table.

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SOURCE QUALIFIER TRANSFORMATION:

• Active and Connected Transformation.
• The Source Qualifier transformation represents the rows that the Power Center Server reads when it runs a session.
• It is only transformation that is not reusable.
• Default transformation except in case of XML or COBOL files.

Tasks performed by Source Qualifier:

• Join data originating from the same source database: We can join two or more tables with primary key-foreign key relationships by linking the sources to one Source Qualifier transformation.
• Filter rows when the Power Center Server reads source data: If we Include a filter condition, the Power Center Server adds a WHERE clause to the Default query.
• Specify an outer join rather than the default inner join: If we include a User-defined join, the Power Center Server replaces the join information Specified by the metadata in the SQL query.
• Specify sorted ports: If we specify a number for sorted ports, the
• Power Center Server adds an ORDER BY clause to the default SQL query.
• Select only distinct values from the source: If we choose Select Distinct,the Power Center Server adds a SELECT DISTINCT statement to the default SQL query.
• Create a custom query to issue a special SELECT statement for the Power Center Server to read source data: For example, you might use a Custom query to perform aggregate calculations. The entire above are possible in Properties Tab of Source Qualifier t/f.

SAMPLE MAPPING TO BE MADE:

• Source will be EMP and DEPT tables.
• Create target table as showed in Picture above.
• Create shortcuts in your folder as needed.

Creating Mapping:

1. Open folder where we want to create the mapping.
2. Click Tools -> Mapping Designer.
3. Click Mapping-> Create-> Give mapping name. Ex: m_SQ_example
4. Drag EMP, DEPT, Target.
5. Right Click SQ_EMP and Select Delete from the mapping.
6. Right Click SQ_DEPT and Select Delete from the mapping.
7. Click Transformation -> Create -> Select Source Qualifier from List -> Give Name -> Click Create
8. Select EMP and DEPT both. Click OK.
9. Link all as shown in above picture.
10. Edit SQ -> Properties Tab -> Open User defined Join -> Give Join condition EMP.DEPTNO=DEPT.DEPTNO. Click Apply -> OK
11. Mapping -> Validate
12. Repository -> Save

• Create Session and Workflow as described earlier. Run the Workflow and see the data in target table.
• Make sure to give connection information for all tables.

SQ PROPERTIES TAB
1) SOURCE FILTER:
We can enter a source filter to reduce the number of rows the Power Center Server queries.
Note: When we enter a source filter in the session properties, we override the customized SQL query in the Source Qualifier transformation.
Steps:

1. In the Mapping Designer, open a Source Qualifier transformation.
2. Select the Properties tab.
3. Click the Open button in the Source Filter field.
4. In the SQL Editor Dialog box, enter the filter. Example: EMP.SAL)2000
5. Click OK.

Validate the mapping. Save it. Now refresh session and save the changes. Now run the workflow and see output.
2) NUMBER OF SORTED PORTS:
When we use sorted ports, the Power Center Server adds the ports to the ORDER BY clause in the default query.
By default it is 0. If we change it to 1, then the data will be sorted by column that is at the top in SQ. Example: DEPTNO in above figure.

• If we want to sort as per ENAME, move ENAME to top.
• If we change it to 2, then data will be sorted by top two columns.

Steps:

1. In the Mapping Designer, open a Source Qualifier transformation.
2. Select the Properties tab.
3. Enter any number instead of zero for Number of Sorted ports.
4. Click Apply -> Click OK.

Validate the mapping. Save it. Now refresh session and save the changes. Now run the workflow and see output.
3) SELECT DISTINCT:
If we want the Power Center Server to select unique values from a source, we can use the Select Distinct option.

• Just check the option in Properties tab to enable it.

4) PRE and POST SQL Commands

• The Power Center Server runs pre-session SQL commands against the source database before it reads the source.
• It runs post-session SQL commands against the source database after it writes to the target.
• Use a semi-colon (;) to separate multiple statements.

5) USER DEFINED JOINS
Entering a user-defined join is similar to entering a custom SQL query. However, we only enter the contents of the WHERE clause, not the entire query.

• We can specify equi join, left outer join and right outer join only. We Cannot specify full outer join. To use full outer join, we need to write SQL Query.

Steps:

1. Open the Source Qualifier transformation, and click the Properties tab.
2. Click the Open button in the User Defined Join field. The SQL Editor Dialog Box appears.
3. Enter the syntax for the join.
4. Click OK -> Again Ok.

Validate the mapping. Save it. Now refresh session and save the changes. Now run the workflow and see output.

Join Type	Syntax
Equi Join	DEPT.DEPTNO=EMP.DEPTNO
Left Outer Join	{EMP LEFT OUTER JOIN DEPT ON DEPT.DEPTNO=EMP.DEPTNO}
Right Outer Join	{EMP RIGHT OUTER JOIN DEPT ON DEPT.DEPTNO=EMP.DEPTNO}

6) SQL QUERY
For relational sources, the Power Center Server generates a query for each Source Qualifier transformation when it runs a session. The default query is a SELECT statement for each source column used in the mapping. In other words, the Power Center Server reads only the columns that are connected to another Transformation.
In mapping above, we are passing only SAL and DEPTNO from SQ_EMP to Aggregator transformation. Default query generated will be:

• SELECT EMP.SAL, EMP.DEPTNO FROM EMP

Viewing the Default Query

1. Open the Source Qualifier transformation, and click the Properties tab.
2. Open SQL Query. The SQL Editor displays.
3. Click Generate SQL.
4. The SQL Editor displays the default query the Power Center Server uses to Select source data.
5. Click Cancel to exit.

Note: If we do not cancel the SQL query, the Power Center Server overrides the default query with the custom SQL query.
We can enter an SQL statement supported by our source database. Before entering the query, connect all the input and output ports we want to use in the mapping.
Example: As in our case, we can’t use full outer join in user defined join, we can write SQL query for FULL OUTER JOIN:
SELECT DEPT.DEPTNO, DEPT.DNAME, DEPT.LOC, EMP.EMPNO, EMP.ENAME, EMP.JOB, EMP.SAL, EMP.COMM, EMP.DEPTNO FROM EMP FULL OUTER JOIN DEPT ON DEPT.DEPTNO=EMP.DEPTNO WHERE SAL>2000

• We also added WHERE clause. We can enter more conditions and write More complex SQL.

We can write any query. We can join as many tables in one query as Required if all are in same database. It is very handy and used in most of the projects.
Important Points:

• When creating a custom SQL query, the SELECT statement must list the port names in the order in which they appear in the transformation.

Example: DEPTNO is top column; DNAME is second in our SQ   mapping.

So when we write SQL Query, SELECT statement have name DNAME first, DNAME second and so on. SELECT DEPT.DEPTNO, DEPT.DNAME

• Once we have written a custom query like above, then this query will Always be used to fetch data from database. In our example, we used WHERE SAL>2000. Now if we use Source Filter and give condition SAL) 1000 or any other, then it will not work. Informatica will always use the custom query only.
• Make sure to test the query in database first before using it in SQL Query. If query is not running in database, then it won’t work in Informatica too.
• Also always connect to the database and validate the SQL in SQL query editor.

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STORED PROCEDURE TRANSFORMATION:

• Passive Transformation
• Connected and Unconnected Transformation
• Stored procedures are stored and run within the database.

A Stored Procedure transformation is an important tool for populating and Maintaining databases. Database administrators create stored procedures to Automate tasks that are too complicated for standard SQL statements.
Use of Stored Procedure in mapping:

• Check the status of a target database before loading data into it.
• Determine if enough space exists in a database.
• Perform a specialized calculation.
• Drop and recreate indexes. Mostly used for this in projects.

Data Passes Between IS and Stored Procedure One of the most useful features of stored procedures is the ability to send data to the stored procedure, and receive data from the stored procedure. There are three types of data that pass between the Integration Service and the stored procedure:
Input/output parameters: Parameters we give as input and the parameters returned from Stored Procedure.
Return values: Value returned by Stored Procedure if any.
Status codes: Status codes provide error handling for the IS during a workflow. The stored procedure issues a status code that notifies whether or not the stored procedure completed successfully. We cannot see this value. The IS uses it to determine whether to continue running the session or stop. Specifying when the Stored Procedure Runs
Normal: The stored procedure runs where the transformation exists in the mapping on a row-by-row basis. We pass some input to procedure and it returns some calculated values. Connected stored procedures run only in normal mode.
Pre-load of the Source: Before the session retrieves data from the source, the stored procedure runs. This is useful for verifying the existence of tables or performing joins of data in a temporary table.
Post-load of the Source: After the session retrieves data from the source, the stored procedure runs. This is useful for removing temporary tables.
Pre-load of the Target: Before the session sends data to the target, the stored procedure runs. This is useful for dropping indexes or disabling constraints.
Post-load of the Target: After the session sends data to the target, the stored procedure runs. This is useful for re-creating indexes on the database.
Using a Stored Procedure in a Mapping :

1. Create the stored procedure in the database.
2. Import or create the Stored Procedure transformation.
3. Determine whether to use the transformation as connected or unconnected.
4. If connected, map the appropriate input and output ports.
5. If unconnected, either configure the stored procedure to run pre- or post-session, or configure it to run from an expression in another transformation.
6. Configure the session.

Stored Procedures:
Connect to Source database and create the stored procedures given below:
CREATE OR REPLACE procedure sp_agg (in_deptno in number, max_sal out number,
min_sal out number, avg_sal out number, sum_sal out number)
As
Begin
select max(Sal),min(sal),avg(sal),sum(sal) into max_sal,min_sal,avg_sal,sum_sal
from emp where deptno=in_deptno group by deptno;
End;
/
CREATE OR REPLACE procedure sp_unconn_1_value(in_deptno in number, max_sal out number)
As
Begin
Select max(Sal) into max_sal from EMP where deptno=in_deptno;
End;
/
1. Connected Stored Procedure T/F
Example: To give input as DEPTNO from DEPT table and find the MAX, MIN, AVG and SUM of SAL from EMP table.

• DEPT will be source table. Create a target table SP_CONN_EXAMPLE with fields DEPTNO, MAX_SAL, MIN_SAL, AVG_SAL & SUM_SAL.
• Write Stored Procedure in Database first and Create shortcuts as needed.

Creating Mapping:
1. Open folder where we want to create the mapping.
2. Click Tools -> Mapping Designer.
3. Click Mapping-> Create-> Give name. Ex: m_SP_CONN_EXAMPLE
4. Drag DEPT and Target table.
5. Transformation -> Import Stored Procedure -> Give Database Connection -> Connect -> Select the procedure sp_agg from the list.

6. Drag DEPTNO from SQ_DEPT to the stored procedure input port and also to DEPTNO port of target.
7. Connect the ports from procedure to target as shown below:
8. Mapping -> Validate
9. Repository -> Save

• Create Session and then workflow.
• Give connection information for all tables.
• Give connection information for Stored Procedure also.
• Run workflow and see the result in table.

2. Unconnected Stored Procedure T/F :
An unconnected Stored Procedure transformation is not directly connected to the flow of data through the mapping. Instead, the stored procedure runs either:

• From an expression: Called from an expression transformation.
• Pre- or post-session: Runs before or after a session.

Method of returning the value of output parameters to a port:

• Assign the output value to a local variable.
• Assign the output value to the system variable PROC_RESULT. (See Later)

Example 1: DEPTNO as input and get MAX of Sal as output.

• DEPT will be source table.
• Create a target table with fields DEPTNO and MAX_SAL of decimal data type.
• Write Stored Procedure in Database first and Create shortcuts as needed.

Creating Mapping:
1. Open folder where we want to create the mapping.
2. Click Tools -> Mapping Designer.
3. Click Mapping-> Create-> Give name. Ex: m_sp_unconn_1_value
4. Drag DEPT and Target table.
5. Transformation -> Import Stored Procedure -> Give Database Connection -> Connect -> Select the procedure sp_unconn_1_value from the list. Click OK.
6. Stored Procedure has been imported.
7. T/F -> Create Expression T/F. Pass DEPTNO from SQ_DEPT to Expression T/F.
8. Edit expression and create an output port OUT_MAX_SAL of decimal data type.
9. Open Expression editor and call the stored procedure as below:Click OK and connect the port from expression to target as in mapping below:

10. Mapping -> Validate
11. Repository Save.

• Create Session and then workflow.
• Give connection information for all tables.
• Give connection information for Stored Procedure also.
• Run workflow and see the result in table.

PROC_RESULT use:

• If the stored procedure returns a single output parameter or a return value, we the reserved variable PROC_RESULT as the output variable.

Example: DEPTNO as Input and MAX Sal as output :
:SP.SP_UNCONN_1_VALUE(DEPTNO,PROC_RESULT)

• If the stored procedure returns multiple output parameters, you must create variables for each output parameter.

Example: DEPTNO as Input and MAX_SAL, MIN_SAL, AVG_SAL and SUM_SAL
as output then:
1. Create four variable ports in expression VAR_MAX_SAL,VAR_MIN_SAL, VAR_AVG_SAL and iVAR_SUM_SAL.
2. Create four output ports in expression OUT_MAX_SAL, OUT_MIN_SAL, OUT_AVG_SAL and OUT_SUM_SAL.
3. Call the procedure in last variable port says VAR_SUM_SAL.
:SP.SP_AGG (DEPTNO, VAR_MAX_SAL,VAR_MIN_SAL, VAR_AVG_SAL, PROC_RESULT)
Example 2:
DEPTNO as Input and MAX_SAL, MIN_SAL, AVG_SAL and SUM_SAL as O/P Stored Procedure to drop index in Pre Load of Target Stored Procedure to create index in Post Load of Target

• DEPT will be source table. Create a target table SP_UNCONN_EXAMPLE with fields DEPTNO, MAX_SAL, MIN_SAL, AVG_SAL & SUM_SAL.
• Write Stored Procedure in Database first and Create shortcuts as needed. Stored procedures are given below to drop and create index on target.Make sure to create target table first. Stored Procedures to be created in next example in Target Database:

Create or replace procedure CREATE_INDEX
As
Begin
Execute immediate 'create index unconn_dept on SP_UNCONN_EXAMPLE(DEPTNO)';
End;
/
Create or replace procedure DROP_INDEX
As
Begin
Execute immediate 'drop index unconn_dept';
End;
/
Creating Mapping:
1. Open folder where we want to create the mapping.
2. Click Tools -> Mapping Designer.
3. Click Mapping-> Create-> Give name. Ex: m_sp_unconn_1_value
4. Drag DEPT and Target table.
5. Transformation -> Import Stored Procedure -> Give Database Connection -> Connect -> Select the procedure sp_agg from the list. Click OK.
6. Stored Procedure has been imported.
7. T/F -> Create Expression T/F. Pass DEPTNO from SQ_DEPT to Expression T/F.
8. Edit Expression and create 4 variable ports and 4 output ports as shown below:

9. Call the procedure in last variable port VAR_SUM_SAL.
10. :SP.SP_AGG (DEPTNO, VAR_MAX_SAL, VAR_MIN_SAL, VAR_AVG_SAL, PROC_RESULT)
11. Click Apply and Ok.
12. Connect to target table as needed.
13. Transformation -> Import Stored Procedure -> Give Database Connection for target -> Connect -> Select the procedure CREATE_INDEX and DROP_INDEX from the list. Click OK.
14. Edit DROP_INDEX -> Properties Tab -> Select Target Pre Load as Stored Procedure Type and in call text write drop_index. Click Apply -> Ok.
15. Edit CREATE_INDEX -> Properties Tab -> Select Target Post Load as Stored Procedure Type and in call text write create_index. Click Apply -> Ok.
16. Mapping -> Validate
17. Repository -> Save

• Create Session and then workflow.
• Give connection information for all tables.
• Give connection information for Stored Procedures also.
• Also make sure that you execute the procedure CREATE_INDEX on database before using them in mapping. This is because, if there is no INDEX on target table, DROP_INDEX will fail and Session will also fail.
• Run workflow and see the result in table.

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