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Showing posts from March, 2011

How to remove/trim special characters in flatfile source field? - Consolidated Info

Que. How to remove special characters like ## in the below ...   Can any one suggest...   Prod_Code   ---   #PC97##   #PC98##   #PC99##   #PC125#   #PC156#   ---   ---   ---   #PC767#   #PC766#   #PC921#   #PC1020   #PC1071   #PC1092   #PC1221   i want to remove that special characters....   i want to load in the target just   Prod_Code   ---   PC9   PC98   PC99   PC125   PC156 . Ans: In expression ,use the replacechar function and in that just replace # with null char. REPLACECHR Availability: Designer Workflow Manager Replaces characters in a string with a single character or no character. REPLACECHR searches the input string for the characters you specify and replaces all occurrences of all characters with the new character you specify. Syntax REPLACECHR( CaseFlag , InputString , OldCharSet , NewChar ) Argument Required/ Optional Description CaseFlag Required Must be an i

What is Delta data load? -> Consolidated Info

A delta load, by definition, is loading incremental changes to the data. When doing a delta load to a fact table, for example, you perform inserts only... appending the change data to the existing table. Top Delta checks can be done in a number of ways. Different logics can accomplish this. One way is to check if the record exists or not by doing a lookup on the keys. Then if the Keys don't exist then it should be inserted as new records and if the record exist then compare the Hash value of non key attributes of the table which are candidates for change. If the Hash values are different then they are updated records. (For Hash Values you can use MD5 function in Informatica) If you are keeping History (Full History) for the table then it adds a little more complexity in the sense that you have to update the old record and insert a new record for changed data. This can also be done with 2 separate tables with one as current version and another as History version.

Define: Surrogate Key -> Consolidated Info

Definition: Surrogate key is a substitution for the natural primary key in Data Warehousing. It is just a unique identifier or number for each row that can be used for the primary key to the table. The only requirement for a surrogate primary key is that it is unique for each row in the table. It is useful because the natural primary key can change and this makes updates more difficult. Surrogated keys are always integer or numeric.  Scenario overview and details To illustrate this example, we will use two made up sources of information to provide data about customers dimension. Each extract contains customer records with a business key (natural key) assigned to it. In order to isolate the data warehouse from source systems, we will introduce a technical surrogate key instead of re-using the source system's natural (business) key. A unique and common surrogate key is a one-field numeric key which is shorter, easier to maintain and understand, and independent from changes i