Configuring the checksum value for loading data into BMC Helix CMDB
About checksum value
You can configure the checksum value for a transformation to load data into BMC Helix CMDB. You can configure a transformation to use the checksum value by selecting the Use CheckSum option in the CMDBOutput step of the transformation. The checksum value is populated in the CheckSum Value field.
A checksum is a unique value generated by BMC Helix CMDB when records from an external data store are inserted into BMC Helix CMDB. If you configure the checksum value, a checksum value is calculated for each data transfer. It is then compared with the checksum value from the previous transfer. This option specifies whether all target records are updated, or only those records that have changed in the source as determined by the checksum calculated from the values of all mapped fields. This option is available only when the direction of the data mapping is External Data into the CMDB.
In Atrium Integrator, the checksum value is calculated using the SHA (Secure Hash Algorithm) logic and this value is calculated for all the fields you have mapped. Field-by-field comparison is not done while updating records in BMC Helix CMDB. Just by refering to the checksum value, decision is made if the record needs to be updated or not. This reduces additional calls made to CMDB to insert records which, also enhances Atrium Integrator's performance.
The following diagram illustrates the usage of checksum value.
Usage of Checksum value
Configuring a transformation to use the checksum value
In Atrium Integrator, the checksum attribute is added only for the BaseElement (CI mappings) and not for BaseRelationship (relationship mapping).
To set checksum for relationship mapping you need to manually add a character type attribute in the BaseRelationship and then proceed with configuring the checksum.
To configure a transformation to use the checksum value
- In Atrium Integrator Spoon, open the transformation you created.
- Double-click the CMDBOutput step.
- Select Use CheckSum.
The checksum value is populated in the pre-defined CheckSumValue field. - (For Atrium Integrator 8.0.0 and earlier) If you are using a field other than Checksum ID to populate the checksum, select that field from the Use Checksum drop-down list.
The checksum value is populated in the selected field. - Save and run the transformation.
If there is a change in the input, the checksum value is updated in the CheckSumValue field and delta of the data is loaded into BMC Helix CMDB.
(For Atrium Integrator 8.0.0 and earlier) If there is a change in the input, the checksum value is updated in the selected field and delta of the data is loaded into BMC Helix CMDB.