Implement array_ndims function #4178
Conversation
| /// Return type of [`array_ndims(array)`](super::functions::array_ndims()) | ||
| #[allow(non_camel_case_types)] | ||
| #[cfg(feature = "postgres_backend")] | ||
| pub type array_ndims<A> = super::functions::array_ndims<SqlTypeOf<A>, A>; |
There was a problem hiding this comment.
Is this even required for functions that do not have a generic return type and always return Integer?
I tried to remove it but without this generic arguments in auto_types explodes.
There was a problem hiding this comment.
It's required for the generic arguments. define_sql_function! generates a function signature as follows:
fn array_ndims<A, Arr>(arr: Arr) -> Integer
where Arr: AsExpression<A>, A: ArrayOrNullableArray + SingleValue>;
The AsExpression part allows us to automatically convert rust values (i.e. vec![1,2,3]) to sql side binds and at the same time it allows us to accept sql side expressions with the same type at the same location (i.e table::array_column). On the other hand the #[auto_type] macro expects exactly as many generic arguments as there are function parameters. The type def in then used to map that.
| /// # use diesel::sql_types::{Nullable, Array, Integer}; | ||
| /// # let connection = &mut establish_connection(); | ||
| /// | ||
| /// let dims = diesel::select(array_ndims::<Array<_>, _>(vec![1, 2])) |
There was a problem hiding this comment.
Not sure why, but it fails to infer the types for Array here.
Same thing since to work for array_append just fine
There was a problem hiding this comment.
It works on array_append because array append has a second argument which is defined
| /// let dims = diesel::select(array_ndims::<Array<_>, _>(vec![1, 2])) | |
| /// let dims = diesel::select(array_ndims::<Array<Integer>, _>(vec![1, 2])) |
| /// # use diesel::sql_types::{Nullable, Array, Integer}; | ||
| /// # let connection = &mut establish_connection(); | ||
| /// | ||
| /// let dims = diesel::select(array_ndims::<Array<_>, _>(vec![1, 2])) |
There was a problem hiding this comment.
It works on array_append because array append has a second argument which is defined
| /// let dims = diesel::select(array_ndims::<Array<_>, _>(vec![1, 2])) | |
| /// let dims = diesel::select(array_ndims::<Array<Integer>, _>(vec![1, 2])) |
weiznich
force-pushed
the
feat/add/array-ndims-function
branch
from
e601cb5 to
18aec7f
Compare
github-merge-queue
bot
removed this pull request from the merge queue due to a conflict with the base branch
weiznich
force-pushed
the
feat/add/array-ndims-function
branch
from
18aec7f to
614df9b
Compare
Adding support for
array_ndimsarray postgresql function.Connected issue: #4153