[hibernate-dev] 6.0 - formalized standard functions

[Sanne Grinovero]

On 30 May 2017 at 13:02, Steve Ebersole <steve at hibernate.org> wrote:
> For whatever reason JPA and a few of the databases do not categorize
> coalesce and nullif as functions - hence the "not technically a function"
> part.
>
> However in Hibernate I have defined them as functions for the sake of users
> being able to plug in custom function templates.

Thanks, it's clear now.

Sanne

>
> On Tue, May 30, 2017 at 5:14 AM Sanne Grinovero <sanne at hibernate.org> wrote:
>>
>> Hi Steve,
>> just a curiosity; for `coalesce` and `nullif` you stated "not
>> technically a function, but supported as such to allow overriding".
>>
>> What does it mean?
>>
>> Thanks!
>> Sanne
>>
>> On 29 May 2017 at 22:29, Steve Ebersole <steve at hibernate.org> wrote:
>> > Hibernate has always defined a set of functions that should always be
>> > available on every Dialect/database.  JPA formalized some of these, but
>> > Hibernate still had a superset.  So I wanted to formalize the complete
>> > set
>> > of supported functions.  Here is the formalized list of what Hibernate
>> > has
>> > always considered the "supported list":
>> >
>> >    - those defined by JPA
>> >    - abs
>> >       - avg
>> >       - concat
>> >       - count
>> >       - current_date
>> >       - current_time
>> >       - current_timestamp
>> >       - length
>> >       - locate
>> >       - lower
>> >       - max
>> >       - min
>> >       - mod
>> >       - sqrt
>> >       - substring
>> >       - sum
>> >       - trim
>> >       - upper
>> >    - Hibernate extensions
>> >    - bit_length
>> >       - coalesce - not technically a function, but supported as such to
>> >       allow overriding
>> >       - cast
>> >       - day - generally defined as `extract(day from ?1)`
>> >       - extract
>> >       - hour - generally defined as `extract(hour from ?1)`
>> >       - minute - generally defined as `extract(minute from ?1)`
>> >       - month - generally defined as `extract(month from ?1)`
>> >       - nullif - not technically a function, but supported as such to
>> > allow
>> >       overriding
>> >       - second - generally defined as `extract(second from ?1)`
>> >       - str - generally defined as `cast(?1 as CHAR )`
>> >       - year - generally defined as `extract(year from ?1)`
>> >
>> >
>> > Additions/subtractions anyone would like to discuss?
>> >
>> > One question I has was in regards to str being defined as `cast(?1 as
>> > CHAR
>> > )` by default - specifically using CHAR instead of VARCHAR.  Some
>> > databases
>> > apply padding for the size of the datatype when casting a numeric to a
>> > CHAR
>> > which is not an unreasonable thing to do.
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