@assert

[StefanHenke]

Describes the basic feature set of the new @assert annotation. The full blown CXN documentation is pending and will be provided by Patrice later. Once available, we will link it here. That´s why the expressions in the examples are kept simple by intention.

[agoerler]

Please introduce in smaller steps

• one case
• multiple cases
• error function

cosider using ? :

Please add some examples for moderately more complex expressions.

Like, e.g.

• "if an order has items the order's total amount must be larger then 0"
• "a book's author's name must not be null"

[StefanHenke]

Please introduce in smaller steps

• one case
• multiple cases
• error function

cosider using ? :

Please add some examples for moderately more complex expressions.

Like, e.g.

• "if an order has items the order's total amount must be larger then 0"
• "a book's author's name must not be null"

What exactly do you mean with consider using ? :`?

We agreed with Johannes and Patrice yesterday that we will keep the expressions simple here and wait for the CXL docs. But I can check for a "moderately more complex expression".

[rjayasinghe]

Please introduce in smaller steps

• one case
• multiple cases
• error function

cosider using ? :
Please add some examples for moderately more complex expressions.
Like, e.g.

• "if an order has items the order's total amount must be larger then 0"
• "a book's author's name must not be null"

What exactly do you mean with consider using ? :`?

We agreed with Johannes and Patrice yesterday that we will keep the expressions simple here and wait for the CXL docs. But I can check for a "moderately more complex expression".

I think @agoerler meant that we split up this single block into 3 examples. After each example we explain the nature of the used expression.

[StefanHenke]

Please introduce in smaller steps

• one case
• multiple cases
• error function

cosider using ? :
Please add some examples for moderately more complex expressions.
Like, e.g.

• "if an order has items the order's total amount must be larger then 0"
• "a book's author's name must not be null"

What exactly do you mean with consider using ? :`?
We agreed with Johannes and Patrice yesterday that we will keep the expressions simple here and wait for the CXL docs. But I can check for a "moderately more complex expression".

I think @agoerler meant that we split up this single block into 3 examples. After each example we explain the nature of the used expression.

Yes, I have split up the examples already. But was not sure if ?: is something in addition

[patricebender]

👍 As Adrian stated, it would be nice to have a little more (complex) real life scenarios. I would have probably taken the well known Bookshop for showcasing the different scenarios. But that may be my personal taste.

[patricebender]

What exactly do you mean with consider using ? :`?

You can use the ternary operator as syntactic sugar for the clumsy case … when … then … statements:

> cds.parse.xpr`1 > 2 ? true : false`
[
  'case',         'when',
  { val: 1 },     '>',
  { val: 2 },     'then',
  { val: true },  'else',
  { val: false }, 'end'
]

[agoerler]

What exactly do you mean with consider using ? :`?

You can use the ternary operator as syntactic sugar for the clumsy case … when … then … statements:

> cds.parse.xpr`1 > 2 ? true : false`
[
  'case',         'when',
  { val: 1 },     '>',
  { val: 2 },     'then',
  { val: true },  'else',
  { val: false }, 'end'
]

@patricebender - could you also omit the :-clause and it would default to else null ? E.g.

size > 100 ? 'size must be below 100'

[StefanHenke]

What exactly do you mean with consider using ? :`?

You can use the ternary operator as syntactic sugar for the clumsy case … when … then … statements:

> cds.parse.xpr`1 > 2 ? true : false`
[
  'case',         'when',
  { val: 1 },     '>',
  { val: 2 },     'then',
  { val: true },  'else',
  { val: false }, 'end'
]

@patricebender - could you also omit the :-clause and it would default to else null ? E.g.

size > 100 ? 'size must be below 100'

That makes sense. When I tested it, compiler still required the default else null a few weeks back.

[StefanHenke]

👍 As Adrian stated, it would be nice to have a little more (complex) real life scenarios. I would have probably taken the well known Bookshop for showcasing the different scenarios. But that may be my personal taste.

I have improved the examples to use Bookshop related entities. Regarding the ternary operator, we still have to put the : else as the compiler complains otherwise.

[agoerler]

I would like to suggest that you introduce a few sub-sections for

• condition
• error messages
• message targets

[StefanHenke]

After incorporating the feedback, I´m asking for another (hopefully final) round of review to the changes approved.

[agoerler]

I think we should mention that @assert should be used on service level.

[agoerler]

the error function will not be release 2025/12