426 IBM WebSphere Information Analyzer and Data Quality Assessment
2.4.1 Step 1: General guidelines for the process
In a migration or a data integration effort, structural and content differences
between the sources and targets will need to be resolved. Table 2-1 shows many
of the commonly encountered differences and potential actions. These actions
are self-explanatory.
We recommend that you define broad action guidelines for mismatches in critical
and non-critical elements between the data sources and targets for the
commonly encountered differences. Consequently, if unexpected differences are
discovered, you can focus your energies on addressing them in the inevitable
time constrained circumstances of migration and data integration projects.
Table 2-1 Commonly encountered differences and potential actions
Commonly encountered differences Potential actions
Data elements in the source not found in the target 򐂰 Add the data elements to the target; significant
impact on target applications likely
򐂰 Ignore it; loss of function
򐂰 Combination of the above depending upon the
data element
Data type mismatch between the source and target
data elements
򐂰 Compatible
򐂰 Incompatible
򐂰 Coarse to fine
򐂰 Fine to coarse
򐂰 Compatible
Simple mapping
򐂰 Incompatible
Use a cross reference table to map from the
source data type to the target data type
򐂰 Coarse to fine
No action other than possible
transformation
򐂰 Fine to coarse
Modify target definition to match fine
granularity of the source; significant impact
on target applications likely
Transform with loss of granularity; loss of
function
Precision, and scale mismatch between the source
and the target data elements
򐂰 Coarse to fine
򐂰 Fine to coarse
򐂰 Coarse to fine
No action other than possible
transformation
򐂰 Fine to coarse
Modify target definition to match fine
granularity of the source; significant impact
on target applications likely
Transform with loss of granularity; loss of
function

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