Example 1:
lets say you have a scenario to compare your target and load the delta by comparing 3 columns (col1 , col2 and col3)...
you create a new column col4 in your target and the output of your new column will be md5(col1 || col2 || col3)
now in your next load you only want to load the delta , drag col1, col2 and col3 in to an expression and create a output port , in the expression editor of your output port you will write the expression md5(col1 || col2 || col3) , instead of comparing all the three columns now you output port from expression to col4.
Example 2:
The MD5 function calculates the checksum of the input value using a cryptographic Message-Digest algorithm 5 and returns a 32 character string of hexadecimal digits (0 - F).
E.g.You want to write changed data to a database. Use MD5 to generate checksum values for rows of data you read from a source. When you run a session, compare the previously generated checksum values against the new checksum values. Then, write the rows with updated checksum values to the target. You can conclude that an updated checksum value indicates that the data has changed.
http://www.disoln.org/2012/08/slowly-changing-dimension-type-2-implementation-using-informatica.html#
please refer to above blog with wonderful and easy to understand examples.
lets say you have a scenario to compare your target and load the delta by comparing 3 columns (col1 , col2 and col3)...
you create a new column col4 in your target and the output of your new column will be md5(col1 || col2 || col3)
now in your next load you only want to load the delta , drag col1, col2 and col3 in to an expression and create a output port , in the expression editor of your output port you will write the expression md5(col1 || col2 || col3) , instead of comparing all the three columns now you output port from expression to col4.
Example 2:
The MD5 function calculates the checksum of the input value using a cryptographic Message-Digest algorithm 5 and returns a 32 character string of hexadecimal digits (0 - F).
E.g.You want to write changed data to a database. Use MD5 to generate checksum values for rows of data you read from a source. When you run a session, compare the previously generated checksum values against the new checksum values. Then, write the rows with updated checksum values to the target. You can conclude that an updated checksum value indicates that the data has changed.
http://www.disoln.org/2012/08/slowly-changing-dimension-type-2-implementation-using-informatica.html#
please refer to above blog with wonderful and easy to understand examples.
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