Error Handling Techinques

Error Handling Techniques are of two types, they are fatal errors and non-fatal errors.

Fatal error force session to fail.
This happens when its unable to access source, target or repository

Non-fatal error does not force session to fail. 
It happens while reading data from source to target. Rejected records will come in this category.

To capture the transformation level errors, we need to enable the property in the configure tab in session properties 'Error Log Type'. 

And we choose DB connection along with the connection information.

As a result 4 error tables are created in database as below :-

PMERR_DATA : This stores Data and Meta data about a transformation row error and its corresponding source rows.
PMERR_MSG : This stores Meta data about an error and error msg
PMERR_SESS : This stores Meta data about session
PMERR_TRANS : This stores Meta data about source and transfomation ports such as name, datatype and when transformation errors occurs. By this we can verify the error, due to which mapping is failing.


Understanding Error Log File :-
---------------------------------
Error Type : 
1 - Reader Error
2 - Writer Error
3 - Transformation Error

Source Row Type :
0 - Insert
1 - Update
2 - Delete
3 - Reject

Source Data :
D - Valid
O - Overflow
N - Null
T - Truncated
B - Binary
U - Data unavailable

Transformation Data :
D - Valid
O - Overflow
N - Null
T - Truncated
B - Binary
U - Data unavailable


Apart from this there are user defined exceptions, we will learn soon about it.