Showing posts with label Database. Show all posts
Showing posts with label Database. Show all posts

Friday, 7 July 2017

ICONV mystery - the UV function


Iconv (Internal CONVersion) is a function supported by UniVerse DB (UV db) to convert the DATA, not only DATE, into internal format. DataStage Server Jobs are using lots of UV functions to manipulate the data.

Today, I will try to unwrap the mystery behind the Iconv function and try to put the details in simpler words. We will not go into data conversion details but date conversion which is used by DataStage :-)

Like most of other date functions (Parallel one), Iconv also accept the date(string) and its format.

Suppose, Date =   June 17, 2017

To Convert this date into internal format, we have to use -

Iconv("2017-06-17", D-YMD)  = 18066
Iconv("2017/06/17", D/YMD)   = 18066
Iconv("2017:17:06", D:YDM)  = 18066
Iconv("17-06-17", D-Y2MD)    = 18066



D-  --> D for Delimiter followed by delimiter char
Y --> year in YYYY
M --> month in MM
D --> date in DD

As we can see, if we provide the date format with date string, Iconv convert the date to an integer no and it is very important to do because now datastage can understand the given date and we can use Oconv function to re-format the date as required.

I will cover Oconv in next post, till then Keep Learning !!




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Thursday, 21 July 2016

DBMS Books



If you dont have the dropbox account, create from here - https://db.tt/H5VKcNA0

Database System Concepts 6E - Korth               Book Link and PPTs Link  
Database System 6E_Navathe - Navathe            Book Link and PPTs Link    





** The books and its content belongs only to its author and publication, Shared here for personal learning purpose. 



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Thursday, 19 May 2016

5 Tips For Better DataStage Design #13



1. The query used in the database should be in such a way that required number of rows are fetched. Do not extract the columns which are not required.

2. For parallel jobs, sequential File should not be read using same partitioning.


http://www.datagenx.net/2016/05/5-tips-for-better-datastage-design-13.html


3. For huge amount of data, use of sequential file stage is not a good practice. This stage also should not be used for intermediate storage between jobs. It degrades the performance of the job.

4. The number of lookups in a job design should be minimum. Join stage is a good alternative to lookup stage.

5. For parallel jobs, proper portioning method is to be used for better job performance and accurate flow of data.





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Tuesday, 15 December 2015

How to use Universe Shell (uvsh) in DataStage?


In DataStage Administration, we have to use datastage command line (universe shell) to get the information directly from the datastage universe database.

While accessing it from command line what novice admin do is -

$ uvsh
This directory is not set up for DataStage.
Would you like to set it up(Y/N)?   
Confused ? What to do ?

Always answer that question "no", it means you're in the wrong place.
Always launch "uvsh" or "dssh" from one of two places - $DSHOME or inside a project directory. For the latter you're good to go, for the former you'll need to LOGTO your project name before you issue any sql.



How to use UVSH?

## Entered into the $DSHOME
$ cd $DSHOME

## Sourced the dsenv file
$ . dsenv

## Change directory to the project directory.
$ LOGTO <project_name>

## Run uvsh command 
$ $DSHOME/bin/uvsh

Many Datastage admin support to execute command from Datastage Administrator or use dssh instead of uvsh.

How to use DSSH?
## Sourced the dsenv file
$ . $DSHOME/dsenv

## Change directory to the project directory.
$ LOGTO <project_name>

## Run dssh command 
$ $DSHOME/bin/dssh



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