Make DataStore::instance_fetch_all less ugly
#5891
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This commit rewrites the `DataStore::instance_fetch_all` query added in #5888 to perform two separate left joins with the `vmm` table, so that the result set only contains a single row. This is a bit more aesthetically pleasing than having to iterate over a multi-row result set, but should still return the same values. Thanks to @jgallagher and @luqmana for figuring out how to do the Diesel alias!
jgallagher
approved these changes
Jun 13, 2024
| let (active_vmm, target_vmm) = | ||
| diesel::alias!(vmm as active_vmm, vmm as target_vmm); | ||
| let vmm_selection = | ||
| <Vmm as Selectable<diesel::pg::Pg>>::construct_selection(); |
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Great find! I looked for something like this hanging off of Alias and came up empty.
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Yeah, there was, as far as I can tell, no actual documentation explaining this usage I found it by looking at the implementation of as_select() and noticed that there was a comment on the Selectable trait saying that the return value from construct_selection() was "usually a tuple of fields".
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This commit rewrites the
DataStore::instance_fetch_allquery added in#5888 to perform two separate left joins with the
vmmtable, so thatthe result set only contains a single row. This is a bit more
aesthetically pleasing than having to iterate over a multi-row result
set, but should still return the same values.
Thanks to @jgallagher and @luqmana for figuring out how to do the Diesel
alias!