Review model changes and metadata

Compare approved DDM models with database structures harvested into DAM to identify tables, columns, views, and property differences. A typical flow reverse engineers a database into DDM, maintains model metadata, then compares and updates approved DAM properties.

DDM handles reverse engineering, design, and model versions. DAM harvests actual structures, initiates comparisons, and reviews governance associations. Confirm objects, versions, and synchronization direction before updating production metadata.

Establish comparable baselines

1. Harvest the target in DAM and verify database, schema, table, and column scope.
2. In DDM Client, reverse engineer the database (Chinese guide) for the same scope.
3. Save to the agreed repository folder and create an identifiable version; record environment and reverse engineering time.
4. Maintain Chinese names, descriptions, standards, column definitions, and properties. Review and publish the comparison version.
5. Align the DAM harvesting time and DDM version before comparing.

DDM can also compare models with reverse engineered databases through model comparison (Chinese guide). Use DAM tasks when applying model results to DAM governance.

Configure comparison in DAM

1. Find the source in Metadata > Datasets and select Model Comparison and Synchronization.
2. Select the approved DDM model/version; verify repository, name, database type, and schema.
3. Enable comparison and select relevant objects and properties.
4. Review additions, deletions, and changes to tables, columns, views, types, length/precision, defaults, keys, and indexes.
5. Retain the report with DAM objects, DDM version, difference types, decisions, and owners.

Have business owners resolve same-name/different-meaning columns. A difference does not prove either baseline is correct.

Review and update metadata

1. Model and database owners classify causes: database ahead of model, model not implemented, stale DAM harvest, or mismatched scope.
2. Enable synchronization for approved business properties only, such as standards, reference codes, Chinese names, descriptions, or custom properties.
3. Apply the available null/conflict policies. Retain the report and test direction with a few objects.
4. Implement physical changes through database change management, then harvest again. Property synchronization does not replace DDL changes.
5. Compare again and retain reasons and owners for unresolved differences.

Check related impacts

After deletions, type changes, or constraint changes, review standards, quality rules, catalogs, metrics, and lineage. Assign owners and record repairs to broken references. Successful harvesting or comparison does not confirm business impact.

Review after execution

Reopen affected objects and inspect structure, names, descriptions, standards, tags, and relationships. Run limited Harvesting, then compare DAM, DDM, and the database against the approved outcome. Handle design, version, and DDL generation issues in DDM records.

Comparison checklist

• Same environment and schema.
• Reviewed model version and suitable DAM harvesting time.
• Report includes all changes and reasons for deferral.
• Confirmed direction and properties; nulls did not overwrite meaningful values.
• Physical changes followed release procedures and DAM was reharvested.
• Standards, quality, assets, metrics, and lineage impacts reviewed.