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