Tuesday, January 18, 2011

Data Mining: An Introduction

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By this point in time, you've probably heard a good deal about data mining -- the database industry's latest buzzword. What's this trend all about? To use a simple analogy, it's finding the proverbial needle in the haystack. In this case, the needle is that single piece of intelligence your business needs and the haystack is the large data warehouse you've built up over a long period of time.

Data Mining in Business

Through the use of automated statistical analysis (or "data mining") techniques, businesses are discovering new trends and patterns of behavior that previously went unnoticed. Once they've uncovered this vital intelligence, it can be used in a predictive manner for a variety of applications. Brian James, assistant coach of the Toronto Raptors, uses data mining techniques to rack and stack his team against the rest of the NBA. The Bank of Montreal's business intelligence and knowledge discovery program is used to gain insight into customer behavior.

Gathering Data

The first step toward building a productive data mining program is, of course, to gather data! Most businesses already perform these data gathering tasks to some extent -- the key here is to locate the data critical to your business, refine it and prepare it for the data mining process. If you're currently tracking customer data in a modern DBMS, chances are you're almost done. Take a look at the article Mining Customer Data from DB2 Magazine for a great feature on preparing your data for the mining process.

Selecting an Algorithm

At this point, take a moment to pat yourself on the back. You have a data warehouse! The next step is to choose one or more data mining algorithms to apply to your problem. If you're just starting out, it's probably a good idea to experiment with several techniques to give yourself a feel for how they work. Your choice of algorithm will depend upon the data you've gathered, the problem you're trying to solve and the computing tools you have available to you. Let's take a brief look at two of the more popular algorithms.

Regression

Regression is the oldest and most well-known statistical technique that the data mining community utilizes. Basically, regression takes a numerical dataset and develops a mathematical formula that fits the data. When you're ready to use the results to predict future behavior, you simply take your new data, plug it into the developed formula and you've got a prediction! The major limitation of this technique is that it only works well with continuous quantitative data (like weight, speed or age). If you're working with categorical data where order is not significant (like color, name or gender) you're better off choosing another technique.

Classification

Working with categorical data or a mixture of continuous numeric and categorical data? Classification analysis might suit your needs well. This technique is capable of processing a wider variety of data than regression and is growing in popularity. You'll also find output that is much easier to interpret. Instead of the complicated mathematical formula given by the regression technique you'll receive a decision tree that requires a series of binary decisions. One popular classification algorithm is the k-means clustering algorithm. Take a look at the Classification Trees chapter from the Electronic Statistics Textbook for in-depth coverage of this technique.

Other Techniques

Regression and classification are two of the more popular classification techniques, but they only form the tip of the iceberg. For a detailed look at other data mining algorithms, look at this feature on Data Mining Techniques or the SPSS Data Mining page.

Data Mining Products

Data mining products are taking the industry by storm. The major database vendors have already taken steps to ensure that their platforms incorporate data mining techniques. Oracle's Data Mining Suite (Darwin) implements classification and regression trees, neural networks, k-nearest neighbors, regression analysis and clustering algorithms. Microsoft's SQL Server also offers data mining functionality through the use of classification trees and clustering algorithms. If you're already working in a statistics environment, you're probably familiar with the data mining algorithm implementations offered by the advanced statistical packages SPSS, SAS, and S-Plus.

Moving On

Have we whetted your appetite for data mining knowledge? For a more detailed look, check out the excellent slide show presentations and other data mining resources on Megaputer.com. If you're ready to get started but can't find any sample data, take a look at the various repositories listed in Data Sources for Knowledge Discovery. Good luck with your data mining endeavors! Stop by our forum and let us know how things are going!

SOURCE:http://databases.about.com/od/datamining/a/datamining.htm
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How important is Extract, Transform, Load (ETL) to data Warehousing?

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Politicians raising money can be used as an analogy to compare data cleansing to data warehousing. There is almost no likelihood of one existing without the other. Data cleansing is often the most time intensive, and contentious, process for data warehousing projects.

What is Data Cleansing?

The elevator pitch: "Data cleansing ensures that undecipherable data does not enter the data warehouse. Undecipherable data will affect reports generated from the data warehouse via OLAP, Data Mining and KPI's."

A very simple example of where data cleansing would be utilized is how dates are stored in separate applications. Example: 11th March 2007 can be stored as '03/11/07' or '11/03/07' among other formats. A data warehousing project would require the different date formats to be transformed to a uniform standard before being entered in the data warehouse.


Why Extract, Transform and Load (ETL)?
Extract, Transform and Load (ETL) refers to a category of tools that can assist in ensuring that data is cleansed, i.e. conforms to a standard, before being entered into the data warehouse. Vendor supplied ETL tools are considerably more easy to utilized for managing data cleansing on an ongoing basis. ETL sits in front of the data warehouse, listening for incoming data. If it comes across data that it has been programmed to transform, it will make the change before loading the data into the data warehouse.
ETL tools can also be utilized to extract data from remote databases either through automatically scheduled events or via manual intervention. There are alternatives to purchasing ETL tools and that will depend on the complexity and budget for your project. Database Administrators (DBAs) can write scripts to perform ETL functionality which can usually suffice for smaller projects. Microsoft's SQL Server comes with a free ETL tool called Data Transforming Service (DTS). DTS is pretty good for a free tool but it does has limitations especially in the ongoing administration of data cleansing.
Example of ETL vendors are Data Mirror, Oracle, IBM, Cognos and SAS. As with all product selections, list what you think you would require from an ETL tool before approaching a vendor. It may be worthwhile to obtain the services of consultants that can assist with the requirements analysis for product selection.
Figure 1. ETL sits in front of Data Warehouses
How important is Data Cleansing and ETL to the success of Data Warehousing Projects?
ETL is often out-of-sight and out-of-mind if the data warehouse is producing the results that match stakeholders expectations. As a results ETL has been dubbed the silent killer of data warehousing projects. Most data warehousing projects experience delays and budget overruns due to unforeseen circumstances relating to data cleansing.
How to Plan for Data Cleansing?
It is important is start mapping out the data that will be entered into the data warehouse as early as possible. This may change as the project matures but the documentation trail will come in extremely valuable as you will need to obtain commitments from data owners that they will not change data formats without prior notice. 
Create a list of data that will require Extracting, Transforming and Loading. Create a separate list for data that has a higher likelihood of changing formats. Decide on whether you need to purchase ETL tools and set aside an overall budget. Obtain advice from experts in the field and evaluate if the product fits into the overall technical hierarchy of your organization.


SOURCE:http://www.dwreview.com/Articles/Data_Cleansing.html
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Informatica Repository Manager

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Q. What type of repositories can be created using Informatica Repository Manager?

A. Informatica PowerCenter includeds following type of repositories :

    Standalone Repository : A repository that functions individually and this is unrelated to any other repositories.
    Global Repository : This is a centralized repository in a domain. This repository can contain shared objects across the repositories in a domain. The objects are shared through global shortcuts.
    Local Repository : Local repository is within a domain and it’s not a global repository. Local repository can connect to a global repository using global shortcuts and can use objects in it’s shared folders.
    Versioned Repository : This can either be local or global repository but it allows version control for the repository. A versioned repository can store multiple copies, or versions of an object. This features allows to efficiently develop, test and deploy metadata in the production environment.

Q. What is a code page?

A. A code page contains encoding to specify characters in a set of one or more languages. The code page is selected based on source of the data. For example if source contains Japanese text then the code page should be selected to support Japanese text.

When a code page is chosen, the program or application for which the code page is set, refers to a specific set of data that describes the characters the application recognizes. This influences the way that application stores, receives, and sends character data.

Q. Which all databases PowerCenter Server on Windows can connect to?

A. PowerCenter Server on Windows can connect to following databases:

    IBM DB2
    Informix
    Microsoft Access
    Microsoft Excel
    Microsoft SQL Server
    Oracle
    Sybase
    Teradata

Q. Which all databases PowerCenter Server on UNIX can connect to?

A. PowerCenter Server on UNIX can connect to following databases:

    IBM DB2
    Informix
    Oracle
    Sybase
    Teradata

Infomratica Mapping Designer

Q. How to execute PL/SQL script from Informatica mapping?

A. Stored Procedure (SP) transformation can be used to execute PL/SQL Scripts. In SP Transformation PL/SQL procedure name can be specified. Whenever the session is executed, the session will call the pl/sql procedure.

Q. How can you define a transformation? What are different types of transformations available in Informatica?

A. A transformation is a repository object that generates, modifies, or passes data. The Designer provides a set of transformations that perform specific functions. For example, an Aggregator transformation performs calculations on groups of data. Below are the various transformations available in Informatica:

    Aggregator
    Application Source Qualifier
    Custom
    Expression
    External Procedure
    Filter
    Input
    Joiner
    Lookup
    Normalizer
    Output
    Rank
    Router
    Sequence Generator
    Sorter
    Source Qualifier
    Stored Procedure
    Transaction Control
    Union
    Update Strategy
    XML Generator
    XML Parser
    XML Source Qualifier

Q. What is a source qualifier? What is meant by Query Override?

A. Source Qualifier represents the rows that the PowerCenter Server reads from a relational or flat file source when it runs a session. When a relational or a flat file source definition is added to a mapping, it is connected to a Source Qualifier transformation.

PowerCenter Server generates a query for each Source Qualifier Transformation whenever it runs the session. The default query is SELET statement containing all the source columns. Source Qualifier has capability to override this default query by changing the default settings of the transformation properties. The list of selected ports or the order they appear in the default query should not be changed in overridden query.

Q. What is aggregator transformation?

A. The Aggregator transformation allows performing aggregate calculations, such as averages and sums. Unlike Expression Transformation, the Aggregator transformation can only be used to perform calculations on groups. The Expression transformation permits calculations on a row-by-row basis only.

Aggregator Transformation contains group by ports that indicate how to group the data. While grouping the data, the aggregator transformation outputs the last row of each group unless otherwise specified in the transformation properties.

Various group by functions available in Informatica are : AVG, COUNT, FIRST, LAST, MAX, MEDIAN, MIN, PERCENTILE, STDDEV, SUM, VARIANCE.

Q. What is Incremental Aggregation?

A. Whenever a session is created for a mapping Aggregate Transformation, the session option for Incremental Aggregation can be enabled. When PowerCenter performs incremental aggregation, it passes new source data through the mapping and uses historical cache data to perform new aggregation calculations incrementally.

Q. How Union Transformation is used?

A. The union transformation is a multiple input group transformation that can be used to merge data from various sources (or pipelines). This transformation works just like UNION ALL statement in SQL, that is used to combine result set of two SELECT statements.

Q. Can two flat files be joined with Joiner Transformation?

A. Yes, joiner transformation can be used to join data from two flat file sources.

Q. What is a look up transformation?

A. This transformation is used to lookup data in a flat file or a relational table, view or synonym. It compares lookup transformation ports (input ports) to the source column values based on the lookup condition. Later returned values can be passed to other transformations.

Q. Can a lookup be done on Flat Files?

A. Yes.

Q. What is the difference between a connected look up and unconnected look up?

A. Connected lookup takes input values directly from other transformations in the pipleline.

Unconnected lookup doesn’t take inputs directly from any other transformation, but it can be used in any transformation (like expression) and can be invoked as a function using :LKP expression. So, an unconnected lookup can be called multiple times in a mapping.

Q. What is a mapplet?

A. A mapplet is a reusable object that is created using mapplet designer. The mapplet contains set of transformations and it allows us to reuse that transformation logic in multiple mappings.

Q. What does reusable transformation mean?

A. Reusable transformations can be used multiple times in a mapping. The reusable transformation is stored as a metadata separate from any other mapping that uses the transformation. Whenever any changes to a reusable transformation are made, all the mappings where the transformation is used will be invalidated.

Q. What is update strategy and what are the options for update strategy?

A. Informatica processes the source data row-by-row. By default every row is marked to be inserted in the target table. If the row has to be updated/inserted based on some logic Update Strategy transformation is used. The condition can be specified in Update Strategy to mark the processed row for update or insert.

Following options are available for update strategy :

    DD_INSERT : If this is used the Update Strategy flags the row for insertion. Equivalent numeric value of DD_INSERT is 0.
    DD_UPDATE : If this is used the Update Strategy flags the row for update. Equivalent numeric value of DD_UPDATE is 1.
    DD_DELETE : If this is used the Update Strategy flags the row for deletion. Equivalent numeric value of DD_DELETE is 2.
    DD_REJECT : If this is used the Update Strategy flags the row for rejection. Equivalent numeric value of DD_REJECT is 3.
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What is lookup transformation in informatica?

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Lookup is a transformation to look up the values from a relational table/view or a flat file. The developer defines the lookup match criteria. There are two types of Lookups in Powercenter-Designer, namely; 1) Connected Lookup 2) Unconnected Lookup . Different caches can also be used with lookup like static, dynamic, persistent, and shared(The dynamic cache cannot be used while creating an un-connected lookup). Each of these has its own identification. For more details, the book "Informatica Help" can be useful.

Hope you are aware with the basics of Informatica. Now proceeding through lookup transformation.

Lookup transformation is Passive and it can be both Connected and UnConnected as well. It is used to look up data in a relational table, view, or synonym. Lookup definition can be imported either from source or from target tables.

For example, if we want to retrieve all the sales of a product with an ID 10 and assume that the sales data resides in another table called 'Sales'. Here instead of using the sales table as one more source, use Lookup transformation to lookup the data for the product, with ID 10 in sales table.

Difference between Connected and UnConnected Lookup Transformation:

1. Connected lookup receives input values directly from mapping pipeline whereas UnConnected lookup receives values from: LKP expression from another transformation.

2. Connected lookup returns multiple columns from the same row whereas UnConnected lookup has one return port and returns one column from each row.

3. Connected lookup supports user-defined default values whereas UnConnected lookup does not support user defined values.

Example

Select dname from dept,emp where: emp.deptno=dept.deptno

Connected LKPs

    Connected LKP trasformation is one which is connected to Pipe line.
    Connected LKP trasformation will process each and every Row.
    If you want to Use Dynamic LKP cache, use the connected LKP transformation.
    If the LKP condition is not matched the LKP transformation will return the Default Value.
    it cannot be called
    it returns multiple values.
    it can use static or dynamic cache


Unconnected LKPs

    Unconnected LKP trasformation is one which is not connected to the Pipe line.
    It should be called either from expression or Update Stragey.
    It will not process each and evry row. It will return the values based expression Condition.
    If no match found for the LKP condition, the LKP transformation will return Null Values.
    it is a reusable trnsformation. The same LKP trnans can be called multiple times in same mapping
    it will return only one value.
    it can use only static cache


Performance Considerations for Lookups

Below are a list of performance considerations for lookups in Informatica PowerCenter.


Performance for Lookups

Misconceptions about lookup SQL Indexes

I have seen people suggesting an index to improve the performance of any SQL. This suggestion is incorrect - many times. Specially when talking about indexing the condition port columns of Lookup SQL, it is far more "incorrect".

Before explaining why it is incorrect, I would try to detail the functionality of Lookup. To explain the stuff with an example, we take the usual HR schema EMP table. I have EMPNO, ENAME, SALARY as columns in EMP table.

Let us say, there is a lookup in ETL mapping that checks for a particular EMPNO and returns ENAME and SALARY from the Lookup. Now, the output ports for the Lookup are "ENAME" and "SALARY". The condition port is "EMPNO". Imagine that you are facing performance problems with this Lookup and one of the suggestion was to index the condition port.

As suggested (incorrectly) you create an index on EMPNO column in the underlying database table. Practically, the SQL the lookup executes is going to be this:

      select EMPNO,
             ENAME,
             SALARY
      from EMP
      ORDER BY EMPNO,
               ENAME,
               SALARY;

The data resulted from this query is stored in the Lookup cache and then, each record from the source is looked up against this cache. So, the checking against the condition port column is done in the Informatica Lookup cache and "not in the database". So any index created in the database has no effect for this.

You may be wondering if we can replicate the same indexing here in Lookup Cache. You don't have to worry about it. PowerCenter create "index" cache and "data" cache for the Lookup. In this case, condition port data - "EMPNO" is indexed and hashed in "index" cache and the rest along with EMPNO is found in "data" cache.

I hope now you understand why indexing condition port columns doesn't increase performance.

Having said that, I want to take you to a different kind of lookup, where you would've disabled the caching. In this kind of Lookup, there is no cache. Everytime a row is sent into lookup, the SQL is executed against database. In this scenario, the database index "may" work. But, if the performance of the lookup is a problem, then "cache-less" lookup itself may be a problem.

I would go for cache-less lookup if my source data records is less than the number of records in my lookup table. In this case ONLY, indexing the condition ports will work. Everywhere else, it is just a mere chanse of luck, that makes the database pick up index.

Dynamic Lookups

Dynamic Lookups are used for implementing Slowly Changing dimensions. The ability to provide dynamic caching gives Informatica a definetive edge over other vendor products. In a Dynamic Lookup, everytime a new record is found (based on the lookup condition) the Lookup Cache is appended with that record. It can also update existing records in the cache with the incoming values.

SOURCE:http://it.toolbox.com/wiki/index.php/What_is_lookup_transformation_in_informatica%3F
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Friday, January 14, 2011

Slow Running ETL process (read side) & Table Statistics (Oracle).

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Sometimes an ETL process runs considerably slow speed. During test for the small result set it might fly but when a million rows are applied the performance takes a nosedive. There can be many reasons for slow ETL process.  The process can be slow because read, transformation, load. Lets eliminate the transformation and load for the sake of discussion.
For ETL process to be slow on read side here are some reasons .1. No indexes on joins and/or ‘where clause’ 2. Query badly written. 3. Source not analyzed.  Out of these three lets rule out 1 & 2.
In the past most of the databases had RULE based optimizer in the INIT.ORA file, but with new development and specially Data warehouses ‘CHOOSE’ optimizer is preferred. With ‘CHOOSE’ option the query uses COST based optimizer if the statistics are available for the tables in the query.
There are two methods to gather statistics 1. DBMS_STATS package, 2. ANALYZE command. Oracle does not recommend ANALYZE command going forward for various reasons (its a command, cannot analyze external tables, it gathers stats that are not essential, inaccurate stats on partitioned tables and indexes, in future ANALYZE will not support cost-based optimizer, no Monitoring for stale statistics, etc.)
DBMS_STATS.GATHER_SCHEMA_STATS (ownname =>’DWH’, options =>’GATHER AUTO’);
This Package will gather all necessary statistics automatically (there is no need to write a process to check for tables that have stale or no stats). Oracle implicitly determines which objects need new statistics, and determines how to gather those statistics. So once it is put in the ETL flow you can sleep at home and everybody will be happy.
Bottom Line:
After major data load the tables should be analyzed with an automated process. Also please do not use ANALYZE , as in future it will not collect statistics needed for COB. The code can be found here.
1This package should be used as the part of ETL workflow to make sure as batch processes are run the benefit of statistics are available to the next process in the que.
Also ETL programmers can call this package within the ETL process/procedure in the begening so that if the tables required for process are not analyzed they will be analyzed automatically. Also if the procedure is going to modify lot of data in the table then the package can be called just before the end of the procedure.

SOURCE:http://etlguru.com/blog/2006/04/
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Informatica Product Line

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Informatica is a powerful ETL tool from Informatica Corporation, a leading provider of enterprise data integration software and ETL softwares.

The important products provided by Informatica Corporation is provided below:

    Power Center
    Power Mart
    Power Exchange
    Power Center Connect
    Power Channel
    Metadata Exchange
    Power Analyzer
    Super Glue

   

Power Center & Power Mart: Power Mart is a departmental version of Informatica for building, deploying, and managing data warehouses and data marts. Power center is used for corporate enterprise data warehouse and power mart is used for departmental data warehouses like data marts. Power Center supports global repositories and networked repositories and it can be connected to several sources. Power Mart supports single repository and it can be connected to fewer sources when compared to Power Center. Power Mart can extensibily grow to an enterprise implementation and it is easy for developer productivity through a codeless environment.

Power Exchange: Informatica Power Exchange as a stand alone service or along with Power Center, helps organizations leverage data by avoiding manual coding of data extraction programs. Power Exchange supports batch, real time and changed data capture options in main frame(DB2, VSAM, IMS etc.,), mid range (AS400 DB2 etc.,), and for relational databases (oracle, sql server, db2 etc) and flat files in unix, linux and windows systems.

Power Center Connect: This is add on to Informatica Power Center. It helps to extract data and metadata from ERP systems like IBM's MQSeries, Peoplesoft, SAP, Siebel etc. and other third party applications.

Power Channel: This helps to transfer large amount of encrypted and compressed data over LAN, WAN, through Firewalls, tranfer files over FTP, etc.

Meta Data Exchange: Metadata Exchange enables organizations to take advantage of the time and effort already invested in defining data structures within their IT environment when used with Power Center. For example, an organization may be using data modeling tools, such as Erwin, Embarcadero, Oracle designer, Sybase Power Designer etc for developing data models. Functional and technical team should have spent much time and effort in creating the data model's data structures(tables, columns, data types, procedures, functions, triggers etc). By using meta deta exchange, these data structures can be imported into power center to identifiy source and target mappings which leverages time and effort. There is no need for informatica developer to create these data structures once again.

Power Analyzer: Power Analyzer provides organizations with reporting facilities. PowerAnalyzer makes accessing, analyzing, and sharing enterprise data simple and easily available to decision makers. PowerAnalyzer enables to gain insight into business processes and develop business intelligence.

With PowerAnalyzer, an organization can extract, filter, format, and analyze corporate information from data stored in a data warehouse, data mart, operational data store, or otherdata storage models. PowerAnalyzer is best with a dimensional data warehouse in a relational database. It can also run reports on data in any table in a relational database that do not conform to the dimensional model.

Super Glue: Superglue is used for loading metadata in a centralized place from several sources. Reports can be run against this superglue to analyze meta data.


Note:This is not a complete tutorial on Informatica. We will add more Tips and Guidelines on Informatica in near future. Please visit us soon to check back. To know more about Informatica, contact its official website www.informatica.com
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Informatica Software Architecture illustrated

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Informatica ETL product, known as Informatica Power Center consists of 3 main components.
1. Informatica PowerCenter Client Tools:
These are the development tools installed at developer end. These tools enable a developer to
  • Define transformation process, known as mapping. (Designer)
  • Define run-time properties for a mapping, known as sessions (Workflow Manager)
  • Monitor execution of sessions (Workflow Monitor)
  • Manage repository, useful for administrators (Repository Manager)
  • Report Metadata (Metadata Reporter)
2. Informatica PowerCenter Repository:
Repository is the heart of Informatica tools. Repository is a kind of data inventory where all the data related to mappings, sources, targets etc is kept. This is the place where all the metadata for your application is stored. All the client tools and Informatica Server fetch data from Repository. Informatica client and server without repository is same as a PC without memory/harddisk, which has got the ability to process data but has no data to process. This can be treated as backend of Informatica.
3. Informatica PowerCenter Server:
Server is the place, where all the executions take place. Server makes physical connections to sources/targets, fetches data, applies the transformations mentioned in the mapping and loads the data in the target system.
This architecture is visually explained in diagram below:
Sources




Standard: RDBMS, Flat Files, XML, ODBC


Applications: SAP R/3, SAP BW, PeopleSoft, Siebel, JD Edwards, i2


EAI: MQ Series, Tibco, JMS, Web Services


Legacy: Mainframes (DB2, VSAM, IMS, IDMS, Adabas)AS400 (DB2, Flat File)


Remote Sources
Informatica Client Tools, Power Center Repository, Power Center Server
Targets




Standard: RDBMS, Flat Files, XML, ODBC


Applications: SAP R/3, SAP BW, PeopleSoft, Siebel, JD Edwards, i2


EAI: MQ Series, Tibco, JMS, Web Services


Legacy: Mainframes (DB2)AS400 (DB2)


Remote Targets
This is the sufficient knowledge to start with Informatica. So lets go straight to development in Informatica.

 source:http://informatica.techtiks.com/informatica_architecture.html
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Informatica PowerCenter Components

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Informatica PowerCenter is not just a tool but an end-to-end data processing and data integration environment. It facilitates organizations to collect, centrally process and redistribute data. It can be used just to integrate two different systems like SAP and MQ Series or to load data warehouses or Operational Data Stores (ODS).
Now Informatica PowerCenter also includes many add-on tools to report the data being processed, business rules applied and quality of data before and after processing.
To facilitate this PowerCenter is divided into different components:

  • PowerCenter Domain: As Informatica says “The Power Center domain is the primary unit for management and administration within PowerCenter”. Doesn’t make much sense? Right... So here is a simpler version. Power Center domain is the collection of all the servers required to support Power Center functionality. Each domain has gateway (called domain server) hosts. Whenever you want to use Power Center services you send a request to domain server. Based on request type it redirects your request to one of the Power Center services.
  • PowerCenter Repository: Repository is nothing but a relational database which stores all the metadata created in Power Center. Whenever you develop mapping, session, workflow, execute them or do anything meaningful (literally), entries are made in the repository.
  • Integration Service: Integration Service does all the real job. It extracts data from sources, processes it as per the business logic and loads data to targets.
  • Repository Service: Repository Service is the one that understands content of the repository, fetches data from the repository and sends it back to the requesting components (mostly client tools and integration service)
  • PowerCenter Client Tools: The PowerCenter Client consists of multiple tools. They are used to manage users, define sources and targets, build mappings and mapplets with the transformation logic, and create workflows to run the mapping logic. The PowerCenter Client connects to the repository through the Repository Service to fetch details. It connects to the Integration Service to start workflows. So essentially client tools are used to code and give instructions to PowerCenter servers.
  • PowerCenter Administration Console: This is simply a web-based administration tool you can use to administer the PowerCenter installation.
Informatica Components, Repository Manager, Integration Service, Informatica Domain
There are some more not-so-essential-to-know components discussed below:

  • Web Services Hub: Web Services Hub exposes PowerCenter functionality to external clients through web services.
  • SAP BW Service: The SAP BW Service extracts data from and loads data to SAP BW.
  • Data Analyzer: Data Analyzer is like a reporting layer to perform analytics on data warehouse or ODS data.
  • Metadata Manager: Metadata Manager is a metadata management tool that you can use to browse and analyze metadata from disparate metadata repositories. It shows how the data is acquired, what business rules are applied and where data is populated in readable reports.
  • PowerCenter Repository Reports: PowerCenter Repository Reports are a set of prepackaged Data Analyzer reports and dashboards to help you analyze and manage PowerCenter metadata.
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Informatica Transformations

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Normalizer Transformation
Active & Connected. The Normalizer transformation processes multiple-occurring columns or multiple-occurring groups of columns in each source row and returns a row for each instance of the multiple-occurring data. It is used mainly with COBOL sources where most of the time data is stored in de-normalized format.

You can create following Normalizer transformation:
*VSAM Normalizer transformation. A non-reusable transformation that is a Source Qualifier transformation for a COBOL source. VSAM stands for Virtual Storage Access Method, a file access method for IBM mainframe.
*Pipeline Normalizer transformation. A transformation that processes multiple-occurring data from relational tables or flat files. This is default when you create a normalizer transformation.
Components: Transformation, Ports, Properties, Normalizer, Metadata Extensions.

Rank Transformation

Active & Connected. It is used to select the top or bottom rank of data. You can use it to return the largest or smallest numeric value in a port or group or to return the strings at the top or the bottom of a session sort order. For example, to select top 10 Regions where the sales volume was very high or to select 10 lowest priced products. As an active transformation, it might change the number of rows passed through it. Like if you pass 100 rows to the Rank transformation, but select to rank only the top 10 rows, passing from the Rank transformation to another transformation. You can connect ports from only one transformation to the Rank transformation. You can also create local variables and write non-aggregate expressions.

Router Transformation

Active & Connected. It is similar to filter transformation because both allow you to apply a condition to test data. The only difference is, filter transformation drops the data that do not meet the condition whereas router has an option to capture the data that do not meet the condition and route it to a default output group.
If you need to test the same input data based on multiple conditions, use a Router transformation in a mapping instead of creating multiple Filter transformations to perform the same task. The Router transformation is more efficient.
       

Sequence Generator Transformation
Passive & Connected transformation. It is used to create unique primary key values or cycle through a sequential range of numbers or to replace missing primary keys.

It has two output ports: NEXTVAL and CURRVAL. You cannot edit or delete these ports. Likewise, you cannot add ports to the transformation. NEXTVAL port generates a sequence of numbers by connecting it to a transformation or target. CURRVAL is the NEXTVAL value plus one or NEXTVAL plus the Increment By value.
You can make a Sequence Generator reusable, and use it in multiple mappings. You might reuse a Sequence Generator when you perform multiple loads to a single target.
For non-reusable Sequence Generator transformations, Number of Cached Values is set to zero by default, and the Integration Service does not cache values during the session.For non-reusable Sequence Generator transformations, setting Number of Cached Values greater than zero can increase the number of times the Integration Service accesses the repository during the session. It also causes sections of skipped values since unused cached values are discarded at the end of each session.

For reusable Sequence Generator transformations, you can reduce Number of Cached Values to minimize discarded values, however it must be greater than one. When you reduce the Number of Cached Values, you might increase the number of times the Integration Service accesses the repository to cache values during the session.

Sorter Transformation

Active & Connected transformation. It is used sort data either in ascending or descending order according to a specified sort key. You can also configure the Sorter transformation for case-sensitive sorting, and specify whether the output rows should be distinct. When you create a Sorter transformation in a mapping, you specify one or more ports as a sort key and configure each sort key port to sort in ascending or descending order.        

Source Qualifier Transformation
Active & Connected transformation. When adding a relational or a flat file source definition to a mapping, you need to connect it to a Source Qualifier transformation. The Source Qualifier is used to join data originating from the same source database, filter rows when the Integration Service reads source data, Specify an outer join rather than the default inner join and to specify sorted ports.
It is also used to select only distinct values from the source and to create a custom query to issue a special SELECT statement for the Integration Service to read source data

SQL Transformation
Active/Passive & Connected transformation. The SQL transformation processes SQL queries midstream in a pipeline. You can insert, delete, update, and retrieve rows from a database. You can pass the database connection information to the SQL transformation as input data at run time. The transformation processes external SQL scripts or SQL queries that you create in an SQL editor. The SQL transformation processes the query and returns rows and database errors.

Stored Procedure Transformation
Passive & Connected or UnConnected transformation. It is useful to automate time-consuming tasks and it is also used in error handling, to drop and recreate indexes and to determine the space in database, a specialized calculation etc. The stored procedure must exist in the database before creating a Stored Procedure transformation, and the stored procedure can exist in a source, target, or any database with a valid connection to the Informatica Server. Stored Procedure is an executable script with SQL statements and control statements, user-defined variables and conditional statements.

Transaction Control Transformation
Active & Connected. You can control commit and roll back of transactions based on a set of rows that pass through a Transaction Control transformation. Transaction control can be defined within a mapping or within a session.
Components: Transformation, Ports, Properties, Metadata Extensions.

Union Transformation
Active & Connected. The Union transformation is a multiple input group transformation that you use to merge data from multiple pipelines or pipeline branches into one pipeline branch. It merges data from multiple sources similar to the UNION ALL SQL statement to combine the results from two or more SQL statements. Similar to the UNION ALL statement, the Union transformation does not remove duplicate rows.
Rules
1) You can create multiple input groups, but only one output group.
2) All input groups and the output group must have matching ports. The precision, datatype, and scale must be identical across all groups.
3) The Union transformation does not remove duplicate rows. To remove duplicate rows, you must add another transformation such as a Router or Filter transformation.
4) You cannot use a Sequence Generator or Update Strategy transformation upstream from a Union transformation.
5) The Union transformation does not generate transactions.
Components: Transformation tab, Properties tab, Groups tab, Group Ports tab.

Unstructured Data Transformation
Active/Passive and connected. The Unstructured Data transformation is a transformation that processes unstructured and semi-structured file formats, such as messaging formats, HTML pages and PDF documents. It also transforms structured formats such as ACORD, HIPAA, HL7, EDI-X12, EDIFACT, AFP, and SWIFT.
Components: Transformation, Properties, UDT Settings, UDT Ports, Relational Hierarchy.

Update Strategy Transformation
Active & Connected transformation. It is used to update data in target table, either to maintain history of data or recent changes. It flags rows for insert, update, delete or reject within a mapping.

XML Generator Transformation
Active & Connected transformation. It lets you create XML inside a pipeline. The XML Generator transformation accepts data from multiple ports and writes XML through a single output port.

XML Parser Transformation
Active & Connected transformation. The XML Parser transformation lets you extract XML data from messaging systems, such as TIBCO or MQ Series, and from other sources, such as files or databases. The XML Parser transformation functionality is similar to the XML source functionality, except it parses the XML in the pipeline.

XML Source Qualifier Transformation
Active & Connected transformation. XML Source Qualifier is used only with an XML source definition. It represents the data elements that the Informatica Server reads when it executes a session with XML sources. has one input or output port for every column in the XML source.

External Procedure Transformation

Active & Connected/UnConnected transformation. Sometimes, the standard transformations such as Expression transformation may not provide the functionality that you want. In such cases External procedure is useful to develop complex functions within a dynamic link library (DLL) or UNIX shared library, instead of creating the necessary Expression transformations in a mapping.
       

Advanced External Procedure Transformation
Active & Connected transformation. It operates in conjunction with procedures, which are created outside of the Designer interface to extend PowerCenter/PowerMart functionality. It is useful in creating external transformation applications, such as sorting and aggregation, which require all input rows to be processed before emitting any output rows.

SOURCE:http://informatica.techtiks.com/informatica_transformations_3.html
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Tuesday, January 11, 2011

Sigmaways Inc

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Who we are:
Sigmaways is a high end consulting and business-driven IT training establishment founded by a team of veterans who are passionate about sharing the wisdom of knowledge.
Our team has extensive experience in design, implementation and management of enterprise systems and technical training for more than twenty years.
Our Instructors are the finest in the industry, having prior work experience from management consulting firm to Fortune 500 to Startups.
We prepare individuals to lead and lead with skills. We mentor and train individuals to become the very best in their field of study by providing practical guidance from industry experts.
Our workshop based training continually assesses student progress through lab exercises, quizzes, assigned presentations, and one-on-one interviews.
Our training is based on real world business use cases, the very technologies that industry experts implement in real world projects.
We provide suite of technical and business courses to technical and non-technical managers in accelerated formats. Our lab is a virtual training ground where we simulate all IT business scenarios.
Our OBIEE training program will be starting in the first week of October.
Please check the course details for OBIEE training program
Oracle BI Platform (Server Architect / Repository Developer)
Introduction to Dimensional Modeling
Overview of OBEE Platform
Platform Vs Applications Overview
Installation & Configuration
Building Physical layer
Building Business Model Layer
Building Presentation Layer
Creating sample reports
Using flat files and Databases
Building Fact Measures
Building Dimensional Hierarchies
Time Series
Building Level based measures
Adding multiple sources
Aggregate Awareness
Use of Variables
Using Initialization Blocks
Configuring Object Level Security
Cache Management
Concepts of Partition and Fragmentation
Filtering Data
Best practices
Implementation Procedures
Oracle BI Report Developer
Introduction to Dimensional Modeling
Overview of OBEE Platform
Platform Vs Applications Overview
Installation & Configuration
Exploring Answers
Creating Reports
Type of Reports
Guided Navigation
Type of Reports
Guided Navigation
Manage Web Administration
Configuring Delivers / iBots
Best practices
Oracle BI Application Tools (Ware House Developer)
Introduction to Data warehouse
Overview of OBEE Platform
Platform Vs Applications Overview
Introduction to Informatica
Introdution to Data Warehouse
Admin Console (DAC)
Installating & Configuring Informatica
Creating Informatica Mappings
Creating Informatica Workflows
Extract and Loading Data Warehouse
Using Informatica
Data Modelling
Extract Mappings (SDE)
Change Data Capture (CDC)
Executing Mappings (Extract into Staging)
Load Mappings (SIL)
Load into Data warehouse Targets
Using Mapping parameters & Session
Parameters
Introduction to Slowly changing Dimensions
Creating SCD Mappings
Introduction to Aggregates
Installing and Configuring DAC
Exploring DAC Meta Data
Building Custom DAC Meta Data (Stand alone)
Running ETL using DAC
Best Practices
Implementation Procedures
Exploring Oracle BI Applications (DW Application Developer)
Introduction to Data warehouse
Overview of OBEE Platform
Platform Vs Applications Overview
Installation & Configuration
Exploring OOTB Informatica Metadata
Exploring DAC Meta Data
System Configuration
Source Specific Configuration (EBS)
Functional Configuration (Order Management)
Running ETL Workshop
Exploring OOTB Repository
Exploring OOTB Reports / Dashboards
Upgrade Best Practices
Implementation Procedures
The above course can also be divided into 2 separate programs
1. OBIEE Platform
2. OBIEE Applications
The fees structure for these programs will be $750 each.
If you want to take a both the programs then there will be around 20 discount and the fees will be $1200. The batch starts soo so please get in touch with me ASAP.

source:http://www.training-classes.com/providers/00/68/6859_sigmaways_inc.php
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