feat: standard database functions everywhere #1750

patricebender · 2025-04-01T14:53:28Z

The cds-compiler and the node database services now are on-par with regard to the supported standard database functions.

With this change we move the standard database function section out of the "runtime" part. Once CAP Java closed the gap, we can remove the disclaimer that this is only available for cds-compiler + node database services

The cds-compiler and the node database services now are on-par with regard to the supported standard database functions. With this change we move the standard database function section out of the "runtime" part. Once CAP Java closed the gap, we can remove the disclaimer that this is only available for cds-compiler + node database services

agoerler · 2025-04-01T15:02:49Z

guides/databases.md

+#### String Functions
+
+- `concat(x, y, ...)`
+  Concatenates the given strings or numbers.


not available in CAP Java

do you support the concat operator (||) ?

https://github.wdf.sap.corp/cds-java/home/issues/1998

returns String

Yes we support the concat operator

agoerler · 2025-04-01T15:03:14Z

guides/databases.md

+  Concatenates the given strings or numbers.
+
+- `trim(x)`
+  Removes leading and trailing whitespaces.


not available in CAP Java

returns String

agoerler · 2025-04-01T15:06:42Z

guides/databases.md

+  Removes leading and trailing whitespaces.
+
+- `contains(x, y)`
+  Checks whether `y` is contained in `x` (fuzzy matching may apply).


CAP Java

Value.contains(other)

Value.contains(other, isCaseInsensitive) to control if case sensitive

Value.contains is exact and never fuzzy

represented by CqnContainmentTest

implemented by LIKE or ILIKE, if available

is the Compiler's implementation case sensitive or case insensitive

OData v4, CAP: case sensitive

OData v4, RAP: case insensitive (!)

returns Boolean

all OData inspired functions are case sensitive

agoerler · 2025-04-01T15:07:09Z

guides/databases.md

+  Checks whether `y` is contained in `x` (fuzzy matching may apply).
+
+- `startswith(x, y)`
+  Checks whether `y` starts with `x`.


CAP Java: startsWith

case sensitive?

return Boolean

all OData inspired functions are case sensitive

agoerler · 2025-04-01T15:07:20Z

guides/databases.md

+- `startswith(x, y)`
+  Checks whether `y` starts with `x`.
+
+- `endswith(x, y)`


CAP Java: endsWith

case sensitive?

return Boolean

all OData inspired functions are case sensitive

agoerler · 2025-04-01T16:50:30Z

guides/databases.md

+- `years_between`
+  Computes the number of years between two specified dates.
+- `months_between`
+  Computes the number of months between two specified dates.
+- `days_between`
+  Computes the number of days between two specified dates.
+- `seconds_between`
+  Computes the number of seconds between two specified dates.
+- `nano100_between`
+  Computes the time difference between two dates to the precision of 0.1 microseconds.


n/a in CAP Java

please link to the corresponding HANA functions.

these functions are very prone to one-off errors -> require a very precise specification

agoerler · 2025-04-01T16:52:04Z

guides/databases.md

+In addition to the OData and SAP HANA standard functions, the **CAP runtimes** provides special functions that are only available for runtime queries:
+
+- `search(xs, y)`
+  Checks whether `y` is contained in any element of `xs` (fuzzy matching may apply).


what is an xs?

please provide an example how this can be used in a view definition

It cant be used in a view defintion as indicated by the section heading and description. I will change xs to x :)

agoerler · 2025-04-01T16:52:58Z

guides/databases.md

+#### Numeric Functions
+
+- `ceiling(x)`
+  Rounds the numeric parameter up to the nearest integer.


n/a in CAP Java

agoerler · 2025-04-01T16:53:03Z

guides/databases.md

+- `ceiling(x)`
+  Rounds the numeric parameter up to the nearest integer.
+
+- `floor(x)`


n/a in CAP Java

agoerler · 2025-04-01T16:55:23Z

guides/databases.md

+- `session_context(v)`  
+  Utilizes standard variable names to maintain session context.
+  Refer to [Session Variables](#session-variables) for additional information.

+- `now()`


In CAP Java you can use the refs $now, $user, $valid.from, $valid.to.

same for node, but this is besides the point of the standard functions. I will add a link to the other section though!

agoerler · 2025-04-01T16:59:40Z

guides/databases.md

@@ -1015,7 +1008,8 @@ In addition to the OData and SAP HANA standard functions, the **CAP runtimes** p
  Utilizes standard variable names to maintain session context.
  Refer to [Session Variables](#session-variables) for additional information.

-
+- `now()`
+  Returns the current datetime.


In CAP Java we have the ref $now but it returns the current Timestamp and not the current DateTime.

In node we return now: () => session_context('$now')` and this in turn returns the current timestamp, thanks for pointing this out. I will adapt the docs :)

agoerler · 2025-04-03T07:27:29Z

guides/databases.md

+  Extracts a substring from `x` starting at index `i` (0-based) with an optional length `n`.
+  - `i`:
+    - Positive: starts at index `i`
+    - Negative: starts `i` positions before the end


This is not covered by OData.

To me it reads like it is:

The two-argument substring function with string parameter values returns a substring of the first parameter string value, starting at the Nth character and finishing at the last character (where N is the second parameter integer value)
A negative start index N, if supported, returns a string/collection starting N characters/items before the end of the string/collection.

we could align the parameter names in our docu with those found in the OData spec

patricebender requested review from agoerler, danjoa and stewsk April 1, 2025 14:53

patricebender requested a review from renejeglinsky as a code owner April 1, 2025 14:53

be more precise

dc8994b

agoerler reviewed Apr 1, 2025

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agoerler reviewed Apr 3, 2025

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feat: standard database functions everywhere #1750

feat: standard database functions everywhere #1750

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feat: standard database functions everywhere #1750

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feat: standard database functions everywhere #1750

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