I am experiencing problems resolving a table schema issue on a shared database where linked tables have incorrect column types, preventing me from pushing changes from to resolve the mismatch. When I attempt to do so, I encounter the following error message:
A column named addresses already exists in the app schema. Migration aborted. Please remove the column before replacing it.
Here is an image depicting the table conflicts:
However, upon inspecting the Contacts table, it appears that the tables are correctly linked:
Nonetheless, the Database Schema reveals the following:
My primary concern is preserving the data in those rows and ensuring that I don’t inadvertently damage the tables in other applications. I am seeking guidance on how to resolve this issue without compromising the data integrity or causing unintended consequences in related applications.
To provide additional context, I would greatly appreciate any insights or recommendations on the following:
- How can I rectify the column type discrepancies between the linked tables without losing existing data?
- What steps can I take to ensure a smooth migration process that resolves the conflicts while maintaining data integrity?
- Are there any best practices or precautions I should consider when working with shared databases and linked tables to prevent similar issues from occurring in the future?
Thank you in advance for your assistance and expertise in addressing this database-related challenge.
Resolution for Linked Table Issues in a Shared Database
I have successfully resolved the problem with the linked tables in the shared database by following these steps:
-
Update the current row name:
- I modified the current row name to a temporary name to avoid conflicts during the resolution process. For example, I renamed
emails to emails_.
-
Utilize the “Resolve Issues” page:
- Navigate to the “Resolve Issues” page in the database management system.
- Push the new temporary name (
emails_) to the desired table where the conflict exists.
- Subsequently, push a blank space to the same table to effectively remove the conflicting column.
-
Restore the original row name:
- After resolving the conflict, I renamed the temporary row name (
emails_) back to its original name (email).
By following these steps, I was able to successfully resolve the column type mismatch between the linked tables. The schema resolver handled the column type change without any further manual intervention.
However, I would like to highlight a potential improvement opportunity for the schema resolver. It would be more efficient and user-friendly if the schema resolver could automatically handle column type changes without requiring the aforementioned workaround. This enhancement would streamline the process and reduce the manual effort needed to resolve such conflicts.
A word of caution for anyone trying this approach: removing a column removes its data, too. That may not have mattered in this case. It might matter in yours.
That said, there certainly are cases when changing the column type could preserve its data, and that would be a nice option to have.
In the absence of that, data preservation and conversion requires a bit of coding, and probably one or more temporary columns for the migration’s duration.
This work around prevented me from losing the data. That was the point of frustration with the error message I got from Anvil.
You left out a few details, so I probably made a bad inference. It wasn’t immediately clear in which database you did the renames, nor was it clear which of the two (left or right) was your intended destination.
In the Table Editor, when I rename a column, it keeps its data and its type. Renaming it back also keeps its data and its type. Inserting a new column creates a column full of Nones. Deleting a column removes its name, type, and data. I’ve never seen it do otherwise.
If you’ve actually managed to change a column’s type, without losing its data, that would be a game-changer for a lot of developers here. I’d love to see anyone reproduce that, step by step, no details left out.
I apologize if my explanation was not the best, being descriptive is not always my strong suit. When I get a little more time, I’ll try to make a step-by-step of what I did.
