Hi Lukas
Just to clarify:
>> 4. The Record.from() method simply uses reflection to take each
attribute from your POJO and set the corresponding value of your record
using setValue(), unless:
>> a) The value is null and the corresponding Field is NOT NULL
That means that if POJO has field with null value, than record filed will
be unchanged after Record.from() ? It shold be changed.
четверг, 11 июня 2015 г., 12:17:09 UTC+3 пользователь Lukas Eder написал:
>
> OK, no worries. Let's review the jOOQ API. Perhaps, you're confusing
> different methods and their behaviours / implications on the resulting query
>
> среда, 10 июня 2015 г., 18:30:28 UTC+3 пользователь Robert DiFalco написал:
>
>> Sorry for belaboring this but I still don't see a clear answer to the
>> question. I suppose I could just look at the code but...
>>
>> Many of us have beans whose fields we may populate from the database.
>> Then a user may modify some of the field in this bean/record. When we then
>> do an update are only the fields that have been modified updated for that
>> row? I would expect JOOQ to only update the fields that have been modified
>> in code, not those that were retrieved from the database and have not been
>> "changed".
>>
>
> Let's establish two terms first, to avoid confusion.
>
> - "changed" is what jOOQ understands and implements in Record.changed(). A
> value may be "changed" without being "modified"
> - "modified" is what you probably understand by transitioning a value from
> A to B, such that java.util.Objects.equals(A, B) == false
>
> How does "changed" work?
>
> 1. As Oleg also correctly mentioned, jOOQ cannot intercept what you do
> with your Beans / DTOs ("POJOs"). Other frameworks might make use of
> instrumentation / bytecode magic, but we don't. So modifications to the
> beans and its attributes are transparent to jOOQ
>
> 2. A Record contains a state machine that takes into account a variety of
> ActiveRecord use-cases. Most importantly, it will avoid rendering
> "unchanged" values to resulting INSERT or UPDATE statements. jOOQ does this
> to allow for the application of triggers and DEFAULT values in the
> database, mostly on INSERT.
>
> 3. The "changed" flag for a Record's Field is set to true if:
>
> a) You set it to true explicitly via a Record.changed() method
> b) The field is a non-primary key field and you call Record.setValue()
> (or some overload / generated variant thereof) on it
> c) The field is a primary key field and you call Record.setValue() (or
> some ...) on it with Settings.updatablePrimaryKeys set to true
> d) The field is a primary key field of a "new" record (not previously
> fetched from the database) and you call Record.setValue() (or some ...)
> on it.
> e) You call Record.setValue() (...) on a primary key field of a
> previously fetched record, "modifying" it to a new value (this is a legacy
> feature in jOOQ, as jOOQ used to interpret primary key modifications as a
> hint to copy a record. Obviously only when Settings.updatablePrimaryKeys is
> false)
>
> 4. The Record.from() method simply uses reflection to take each attribute
> from your POJO and set the corresponding value of your record using
> setValue(), unless:
>
> a) The value is null and the corresponding Field is NOT NULL
>
> I suspect that your confusion originates from a missing 4b), which would
> imply that Record.from() should not call setValue() on values that will not
> be "modified". We cannot, however, implement such a change
> backwards-compatibly, and I think that it would be wrong in the event of a
> nullable column with a DEFAULT value.
>
> I hope this clarifies things a bit?
>
> 2015-06-10 17:51 GMT+02:00 Oleg <[email protected] <javascript:>>:
>
>> I think JOOQ cannot detect changes made in DTO, because there is no
>> connection between it and jooq record.
>>
>> As I understand, since 3.6 changes made via record will cause update only
>> changed fields.
>>
>
> We haven't really changed the behaviour of all of this, just made the
> behaviour more consistent, such that the following two will have roughly
> the same effect:
>
> record.store()
> DSL.using(configuration).update(TABLE).set(record).where(...).execute();
>
>
>
>> Also, converting DTO, where number of fields is less than in JOOQ record,
>> to JOOQ record will also cause update only fields contained in DTO.
>>
>
> Exactly.
>
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