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Topic structure updates in a relational database

When you edit the structure of a topic with associated publications or subscriptions in a relational database, it might affect the associated publications and subscriptions. Topic structure changes might also impact the data in the publication repository and sometimes cause data loss.

Based on the nature of the update, you might have to edit the associated publications and subscriptions to align with the updated topic structure. Topic updates require that no publication or subscription events be in Processing or Delayed status. Search for any publication or subscription events that are in Processing status on the

Events

page and change their status to Discarded before you update them. For more information, see Discarding all events in Processing status.

The following table describes the effects of topic structure updates on data in the publication repository and the resulting optional or required changes to the associated publications and subscriptions.

Topic Structure Update	Effect on Data in Publication Repository ¹	Optional/Required Changes to Associated Publications and Subscriptions
Add table	Table added	Optional: To publish and to consume the additional table, edit the mapping to include the additional table. If you do not update the mapping, data in the table will not be published to the publication repository and subscribers will not receive it.
Delete table	Table deleted, including data that was published to the table	Remove references to the table from the mapping of publications and from the mapping and the filter of subscriptions.
Add column	Column added	Optional: To publish and to consume the additional column, edit the mapping to include the additional column. If you do not update the mapping, data in the column will not be published to the publication repository and subscribers will not receive it.
Delete column	Column deleted, including data that was published to the column	Remove references to the column from the mapping of publications and from the mapping and the filter of subscriptions.
Rename column	Column deleted, including data that was published to the column, and another column created with new name	Remove references to the changed column from the mapping of publications and from the mapping and the filter of subscriptions. Optional: To publish or to consume the column that is created with a new name, edit the mapping to include the new column. If you do not update the mapping, data in the new column will not be published to the publication repository and subscribers will not receive it.
Change column data type	Column deleted, including data that was published to the column, and another column created with new data type	Remove references to the changed column from the mapping of publications and from the mapping and the filter of subscriptions. Optional: To publish or to consume the column that is created with the new data type, edit the mapping to include the new column. If you do not update the mapping, data in the new column will not be published to the publication repository and subscribers will not receive it.
Increase column precision, scale unchanged	Column updated	Open the publication or the subscription page for all associated publications and subscriptions. You do not need to edit any of the publication or subscription settings.
Increase column precision, increase scale by a lower value than the precision increase or by the same value as the precision increase	Column updated	Open the publication or the subscription page for all associated publications and subscriptions. You do not need to edit any of the publication or subscription settings.
Any other precision or scale updates	Column deleted, including data that was published to the column, and another column created with updated precision or scale	Remove references to the changed column from the mapping of publications and from the mapping and the filter of subscriptions. Optional: To publish or to consume the column that is created with the new precision or the new scale, edit the mapping to include the new column. If you do not update the mapping, data in the new column will not be published to the publication repository and subscribers will not receive it.