51 lines
1.4 KiB
Plaintext
51 lines
1.4 KiB
Plaintext
namespace sap.capire.bookshop;
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using from '../db/schema';
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/**
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* Validation constraints for Books
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*/
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view Books.constraints as select from Books { ID,
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// two-step mandatory check
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title = null ? 'is missing' : trim(title)='' ? 'must not be empty' :
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null as title,
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// range check
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stock < 0 ? 'must not be negative' :
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null as stock,
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// range check
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price < 0 ? 'must not be negative' :
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null as price,
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// assert target check
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genre.ID is not null and not exists genre ? 'does not exist' :
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null as genre,
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// multiple constraints: mandatory + assert target + special
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not exists author ? 'Author does not exist: ' || author.ID :
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author.ID is null ? 'is missing' : // FIXME: expected author.ID to refer to foreign key, apparently that is not the case -> move one line up to see
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count(author.books.ID) -1 > 1 ? author.name || ' already wrote multiple books, please choose another author' : // TODO: we should support count(author.books)
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null as author,
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} group by ID;
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/**
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* Validation constraints for Authors
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*/
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view Authors.constraints as select from Authors { ID,
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// two-step mandatory check
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name = null ? 'is missing' : trim(name)='' ? 'must not be empty' :
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null as name,
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// constraint related to two fields
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dateOfDeath > dateOfBirth ? 'date of birth must be before date of death' : null as _born_before_death,
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$self._born_before_death as dateOfBirth,
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$self._born_before_death as dateOfDeath,
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}
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