Home/ Questions/Q 699269
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-14T03:22:04+00:00

Under what circumstances (if any) would you allow an application to change its underlying

  • 0

Under what circumstances (if any) would you allow an application to change its underlying database schema? I.e. to add new column.

EDIT: A little bit of elaboration on what prompted me to ash this question. My system receives raport files from other systems and saves fetched data in “reports” table. Report includes several “parameters” which are now hard-coded: date, amount, unit_price. This parameters are saved in adequate columns in “reports” table.
We need to introduce the possibility of dynamically (via web interface) adding new parameters which can be read from report file and inserted to db.

One option is to save reports in some serialized form but there’s performance issue. There will be thousands of reports each day and there will be a need to query “reports” table by parameters’ values.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    On first load of a new version. This is especailly relevant for systems which assign a database to each unique instance. Data writes should be marked with a system variable, and tested before update with something like

    show columns from test like 'new_column';
if ( ! new_column )
  alter table add column new_column after some_column

    With regards to the other posts, if you are running a system with incremental versioning on the same database schemas (but different instances of those schemas) the only way to manage that change is to programmatically update the database – otherwise you’ll have inconsistencies between the application versions (i.e. 1.0 and 1.1) and the schemas – it’s not possible to apply the database changes across all databases at the same time in this instance.

    • 0