Since I want to allow users to empty the field later, the workflow would be:
- add "notnull=True" to the definition
- update code, perform the migration
- remove "notnull=True" from the defintion
- update code again
Still not very elegant, but maybe easier than my previous recipe. Thanks
for that idea!
valq...@gmail.com schrieb am Sonntag, 17. Januar 2021 um 19:02:41 UTC+1:
>
> Field(..., notnull = True) does the trick
> суббота, 16 января 2021 г. в 21:39:00 UTC+3, ferm...@googlemail.com:
>
>> Hi,
>>
>> I need to add a new column with default values to an existing table.
>>
>> In the model file, I add
>> SQLField('newcolumn', type='text', default= 'Default text' )
>> to the db.define_table('mytest', ...) command.
>>
>> After migration, all *newly* inserted tuples get 'Default text' in the
>> column 'newcolumn' and the SQLForms are pre-populated with that value,
>> which is the desired behavior.
>>
>> However, all *existing* tuples in the table have a NULL value in that
>> column, which is not desired.
>>
>> The sql.log shows that the migration command is:
>> ALTER TABLE "mytest" ADD "newcolumn" CHAR(512);
>>
>> What I would need instead is:
>> ALTER TABLE "mytest" ADD "newcolumn" CHAR(512) DEFAULT "Default text";
>>
>> So my question is: How do I populate existing tuples with default values
>> when migrating?
>>
>> Is there an elegant, web2py supported way or do I have to do it manually?
>>
>> And if I have to do it manually: Is there a good recipe for it?
>> My current idea would be to turn migration off on the productive system,
>> perform migration on the testing system, copy and edit the commands from
>> the sql.log on the testing system and run them on the DB system of the
>> productive system (which is Postgres).
>> However, there might be better ways to do that ...
>>
>> I already searched the web2py book and this forum for that issue, but I
>> only found a recipe on how to Populate on Deployment (
>> http://web2py.com/books/default/chapter/29/13/deployment-recipes#Populating-a-Database-on-Deployment),
>>
>> not on Migration.
>>
>> Any hints would be highly welcome!
>>
>> Daniela
>>
>>
>>
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