[protobuf] Re: Handle data migration. e.g. moving of field - Java

2016-02-19 Thread 'Josh Haberman' via Protocol Buffers
Yes I think that plan is your best bet. One option is to leave the old 
field in your source code but comment it out, so you have a record of the 
field as it was previously defined. You may also want to mark the field 
numbers and names as "reserved":

https://developers.google.com/protocol-buffers/docs/proto#reserved

On Tuesday, February 16, 2016 at 8:56:05 AM UTC-8, Vincent Dupuis wrote:
>
> I'm facing the exact same problem.
> Did you find any way to migrate data with PB?
> The only way I can think of is to keep generated code of each schema 
> version and program the migration with that.
>
>
> On Thursday, May 8, 2014 at 4:39:50 PM UTC-4, Klaus Kraft wrote:
>>
>> Hi,
>>
>> so far I have defined messages and the only changes I had to handle were 
>> additions and deletions of fields and renamings of fields. It was no 
>> problem to handle this using ProtoBuf. Now I am in the situation that I 
>> defined a message and a field of the message needs to be moved to a field 
>> of another message. How can one handle such a data migration scenario? The 
>> main problem is that I do not want to lose the data that was associated 
>> with the original field that is moved. 
>>
>> I would also be interested in how to handle comparable, complex, data 
>> migration scenarios that go beyond additions, deletions and simple 
>> renamings. If there is no direct support from ProtoBuf, is it possible to 
>> implement migrations in Java (I'm using Java as my target language)?
>>
>> Thanks in advance.
>>
>

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[protobuf] Re: Handle data migration. e.g. moving of field - Java

2016-02-16 Thread Vince
I'm facing the exact same problem.
Did you find any way to migrate data with PB?
The only way I can think of is to keep generated code of each schema 
version and program the migration with that.


On Thursday, May 8, 2014 at 4:39:50 PM UTC-4, Klaus Kraft wrote:
>
> Hi,
>
> so far I have defined messages and the only changes I had to handle were 
> additions and deletions of fields and renamings of fields. It was no 
> problem to handle this using ProtoBuf. Now I am in the situation that I 
> defined a message and a field of the message needs to be moved to a field 
> of another message. How can one handle such a data migration scenario? The 
> main problem is that I do not want to lose the data that was associated 
> with the original field that is moved. 
>
> I would also be interested in how to handle comparable, complex, data 
> migration scenarios that go beyond additions, deletions and simple 
> renamings. If there is no direct support from ProtoBuf, is it possible to 
> implement migrations in Java (I'm using Java as my target language)?
>
> Thanks in advance.
>

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