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SAP CAP Recent Enhancements the HANA Dev Should Know About
Thomas Jung walks through CAP features for HANA database developers that landed through late 2021: doc comments in the data modelData modellingDefining the shape of data before anything serves it: entities and their types, how they relate, and the projections and views that services and applications consume.SAP and community, unassessed (CDL comments propagated into generated database objects via the package.json cdsc.docs compiler option), and schema evolutionSchema evolutionGetting a model change into a database that already holds data, in every tenant, without losing any of it. Generating the initial schema and migrating one that already holds data are often treated as the same step.SAP and community, narrow by design reaching general availability in the November 2021 release, using the @cds.persistence.journal annotation and cds.hana.journal settings to generate incremental hdbmigrationtable migration scripts instead of dropping and recreating tables. It also walks through two features outside those two: window functions in view column definitions, added in the December 2021 release, and a beta assert_integrity setting that generates database foreign-key constraints from 1:1 associations and compositions.
Where it sits
Explains
Schema evolutionCAPSchema evolutionGetting a model change into a database that already holds data, in every tenant, without losing any of it. Generating the initial schema and migrating one that already holds data are often treated as the same step.Data modellingCAPData modellingDefining the shape of data before anything serves it: entities and their types, how they relate, and the projections and views that services and applications consume.
Since then
Data modelling has changed 3 times since this was published, most recently in @sap/cds 9.9.0, 2026-04-23
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reachable
Who is behind it
Thomas JungThomas JungWrote this
Developer Advocate
In the atlas: contributes to 15, wrote 6@jung-thomasauthor
Developer Advocate
In the atlas: contributes to 15, wrote 6@jung-thomasauthor
Before you read it
ApplicabilityCore changedData modelling has changed 3 times since this was published, most recently in @sap/cds 9.9.0, 2026-04-23.
This is a derived prompt to re-check the work, not a claim that the work is wrong. Exact stale statements are recorded separately after editorial review.
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About this work
For data-modelling
Applies in
Group by25 of 25 pieces
Piece, what it offersStill applies
SAP Developer New, July 3rd 2026SAP Developer New, July 3rd 2026A "Did You Know" segment in this SAP Developer News video walks through schema evolution: CAP's ability to add a new field to an entity, or make a compatible change to an existing one, then redeploy the model with no data loss or manual migration. The rest of the July 2026 episode covers that month's Developer Challenge, a SAP HANA Cloud Q2 release announcement and a UI5 survey call, none explained in substance here.published 2026-07-02
Deep Insert in SAP CAPM Using Composition and Fiori ElementsDeep Insert in SAP CAPM Using Composition and Fiori ElementsParent and children created in one transaction, which composition already gives you in the model — the post is about what Fiori elements does with it, and what the payload looks like when the UI sends both at once.published 2026-05-22
Building an Enterprise Application Using Fiori Elements and CAP - Part 1Building an Enterprise Application Using Fiori Elements and CAP - Part 1Part one of three, and it is all backend: the CAP service the UI will sit on. The author states the constraint the series works under — simple enough for someone new to the stack, without departing from the standard project layout.Farooq, published 2025-12-10
Create CDS Views and expose through OData service in CAPMCreate CDS Views and expose through OData service in CAPMViews defined in CDS and then exposed, which is the whole of what a small CAP service is. Written step by step from cds init onward in Business Application Studio.VenkateshMundru, published 2025-08-11
A CAP Plugin for Flexible Number Range Management: cds-numberrange-pluginA CAP Plugin for Flexible Number Range Management: cds-numberrange-pluginThe author's own plugin, and the reason given for writing it is about plugins rather than about number ranges: a year of using them convinced them that this was the way to extend CAP without leaving marks on the application. Sequential document numbers are the thing it does; keeping the host project clean is the thing it argues for.abdulbasit, published 2025-06-17
Understanding Projections in CAPM: Select Only What You Need!Understanding Projections in CAPM: Select Only What You Need!One concept, explained by someone who had just learned it and says so — what a projection is, why it matters, and an analogy. The register is unusual here and suits the subject: projections are the first thing that makes CDS feel different from a table.Avisek_, published 2025-06-10
HANA Database Migration: Handling Incompatible Changes to Existing TablesHANA Database Migration: Handling Incompatible Changes to Existing TablesThe question schema evolution exists for, asked plainly: how do you restructure a table in a production system that already holds live data. Incompatible changes are the ones CAP's own alter path will not make, which is where this starts.Sekar Somasundaram, published 2025-04-16
CAP, CDS, CDL, CSN and jq - finding associationsCAP, CDS, CDL, CSN and jq - finding associationsHow associations are actually represented once CDL is compiled into CSN, worked out by parsing the machine-readable form with jq. Useful less as a recipe than as a way in: anything that wants to reason about a CDS model without the compiler has to read CSN, and this is what that looks like from the outside.published 2024-04-16
SAP CAP(Cloud Application Programming)开发框架概述SAP CAP(Cloud Application Programming)开发框架概述A Chinese-language walkthrough of CAP built mainly from CAPire's own "About CAP" page: CDS entities, associations, compositions and aspects for data modelling, with an extend Books with @restrict: [{ grant:'WRITE', to:'admin' }] aspect as its authorization example; CQL and CQN queries shown against both a local service and OData's $select/$expand; and the service-and-event model — this.on, this.emit, srv.on — that carries CAP's async processing. It closes with the author's own setup: installing @sap/cds-dk, scaffolding a bookshop project with cds init, and running it with cds watch against local SQLite, mocked authentication and file-based messaging standing in for HANA Cloud, IAS and Kafka.ArthurYang, published 2024-01-07
Run and Deploy SAP CAP (Node.js or Java) with PostgreSQL on SAP BTP Cloud FoundryRun and Deploy SAP CAP (Node.js or Java) with PostgreSQL on SAP BTP Cloud FoundryBoth runtimes in one walkthrough, and it stops on schema evolution — which is the reason to read it rather than one of the several other PostgreSQL posts here, since that is where the PostgreSQL story diverges from HANA's and the deploy stops being automatic.TiaXu, published 2023-07-12
Run and Deploy SAP CAP (Node.js or Java) with PostgreSQL on SAP BTP Cloud Foundry
Database connectors has changed twice since this was published, most recently in @sap/cds 10.1.0, 2026-09-07. Affects A recipe, Runnable code.
#CAP-TechBytes Input Validation#CAP-TechBytes Input ValidationThe annotations one at a time — @mandatory, @assert.unique, @assert.range including the enum form, @assert.format — each with what it produces. Ends on error handling, which is the part that decides whether any of it is usable from a UI.Thajunniza, published 2023-07-07
How I migrated my on-prem xsa cds3+hana solution to cds6+sqliteHow I migrated my on-prem xsa cds3+hana solution to cds6+sqliteThree major CDS versions and a database swap in one move, done to get an old on-premise XSA application running somewhere cheap. The repository is linked, and the interest is in what broke between cds3 and cds6 rather than in the destination.alex_myakinkii, published 2022-08-07
How I migrated my on-prem xsa cds3+hana solution to cds6+sqlite
Database connectors has changed twice since this was published, most recently in @sap/cds 10.1.0, 2026-09-07. Affects Runnable code.
SAP CAP Adapter to expose OData as custom REST ServiceSAP CAP Adapter to expose OData as custom REST ServiceWalks through consuming an external OData V2 service in a CAP project — cds import converts the Northwind service's EDMX into a CSN and cds.connect.to wires up the remote proxy — then re-exposing it as plain REST with the @protocol:'rest' annotation instead of OData's own envelope. Shows two ways to reshape the response, renaming and dropping fields in a CDS projection or rewriting the returned objects in a custom service handler, and remaps ?pageSize and ?offset onto OData's $top and $skip in that same handler.Former Member, published 2021-09-15
Creating structured types, enums and named aspects using the CDS Graphical ModelerCreating structured types, enums and named aspects using the CDS Graphical ModelerThe modelling constructs that are awkward to draw — structured types, enums, named aspects — done in the graphical modeller rather than in CDL.Xiao-fei_Song, published 2021-05-26
Importing @sap/cds common.cds to your CAP project using the CDS Graphical ModelerImporting @sap/cds common.cds to your CAP project using the CDS Graphical ModelerPulling the common aspects and code lists from @sap/cds into a model through the modeller, so the reuse types appear in the diagram rather than only in the file.Xiao-fei_Song, published 2021-05-06
First Java Cap ApplicationFirst Java Cap ApplicationA step-by-step walkthrough of a first CAP Java project: com.sap.cds:cds-services-archetype scaffolds the initial Maven project, and the domain model is then rewritten in the db folder with entities, the cuid and managed aspects, associations, compositions and a CodeList, so a hand-coded event handler serving a single entity gives way to a service that CAP's generic persistence handling serves without custom code. It deploys that model to SQLite for local development — cds deploy --to sqlite, then a Spring profile pointing at the generated database file — and ends by adding an index.cds so the model and service can be published as a reusable npm module.bruce_wang3, published 2020-12-08
Computed field example in CAPComputed field example in CAPAn answer to a Community question — how to count the entities on the far side of an association — written up as a short post rather than left in a thread. The answer combines CDS with Node.js service events, which is the seam worth noticing: some of what looks like modelling is expressed in the model and some has to be computed when the request arrives, and the boundary between them is not obvious from either side.published 2019-08-21
Computed field example in CAP
Data modelling has changed 3 times since this was published, most recently in @sap/cds 9.9.0, 2026-04-23. Affects A recipe, Runnable code.
SAP Cloud Platform Backend service: Tutorial [11]: CDS : magic: key: generationSAP Cloud Platform Backend service: Tutorial [11]: CDS : magic: key: generationExplains CDS's UUID key type: giving a key property UUID gets its value generated automatically instead of a hand-picked unused number, as data modelling lets an element's type do, at the cost of a 36-character value unfit for a user-facing display. It then works out how that generated value is addressed in a single-entity read URL — bare brackets in OData V4 against the guid'...' literal V2 requires — citing the OData specification for the difference.CarlosRoggan, published 2019-03-15
Develop a full stack Business application with SAP Cloud Application Programming ModelDevelop a full stack Business application with SAP Cloud Application Programming ModelBuilds a full-stack CAP application in SAP Web IDE Full Stack's now-retired 'SAP Cloud Platform Business Application' template: a data-model.cds entity with its own service definition, then Fiori annotations on the generated OData. Building the project compiles that model into Catalog.xml and csn.json, the EDMX and CSN that metadata publishing says every exposed service gets. The entity and service definitions it writes by hand are the basic shape data modelling covers, though the webIDE and MTA tooling staged around them is gone.former_member584731, published 2018-11-29
Learn how to define constraints declaratively in your CDS modelLearn how to define constraints declaratively in your CDS modelConstraints expressed in the model rather than checked in a handler — the distinction the atlas draws between input validation the framework enforces and validation somebody writes.SAP
Analyze and optimize ABAP Cloud model apps built on core data servicesAnalyze and optimize ABAP Cloud model apps built on core data servicesPerformance anti-patterns in data models built with ABAP CDS under ABAP Cloud applications, and the tools that find them: the abstract names ABAP cross trace, the SQL analyzer (PlanViz) in Visual Studio Code and the SAP HANA database explorer as what the session uses to follow a bottleneck from the application to the database. The anti-patterns are taken from real business applications, which is where the data modelling edge holds; which ones are shown is not in the abstract. A TechEd 2026 session (Tuesday 27 October, Berlin), presented by Ingo Braeuninger, Robert Werlich, Steffen Siegmund and Thomas Fiedler, written here from SAP's abstract; the recording is not yet published.
SAP Developer New, July 3rd 2026SAP Developer New, July 3rd 2026A "Did You Know" segment in this SAP Developer News video walks through schema evolution: CAP's ability to add a new field to an entity, or make a compatible change to an existing one, then redeploy the model with no data loss or manual migration. The rest of the July 2026 episode covers that month's Developer Challenge, a SAP HANA Cloud Q2 release announcement and a UI5 survey call, none explained in substance here.published 2026-07-02
September 15th: What's New on developers.sap.comSeptember 15th: What's New on developers.sap.comThomas Jung walks through a week of changes aimed at agentic consumption of developers.sap.com itself: the hosted MCP server gains a published .well-known/mcp.json manifest, curated tools (search_tutorials, get_tutorial_step with a Markdown format option, search_channels), and a listing in the ORD catalog beside its OData, REST and GraphQL APIs. It also documents the site's existing A2A endpoint for the first time and ships a way to turn a tutorial into an installable, cryptographically signed AI Skill with a generated verification script, both concrete instances of agent tooling; separately, five broken GraphQL example queries were fixed and the full SDL is now served, and new sitemap.md, llms.txt fixes and ORD entries round out the site's own metadata publishing.published 2026-09-15
SAP Tech Bytes: Adding Service Implementation to an SAP HANA ProjectSAP Tech Bytes: Adding Service Implementation to an SAP HANA ProjectThomas Jung converts an existing SAP HANA-only project into a CAP one, exposing its native tables, views and a calculation view as CAP service entities with @cds.persistence.exists so they get full create, update, delete and read operations without being redefined. He adds OData V2 support through an adapter proxy for callers still expecting XSODATA-shaped responses, and separately turns on CAP's OpenAPI generation with its Swagger UI test tool. A second part rebuilds the same service layer with a standalone Node.js module instead of CAP, for cases that need more control than CAP's REST or OData defaults give.published 2021-05-07
New SAP Cloud Application Programming Model Sample for Many-to-Many Relationships and Fiori AnnotationsNew SAP Cloud Application Programming Model Sample for Many-to-Many Relationships and Fiori AnnotationsIntroduces SAP-samples/cloud-cap-hana-swapi, a CAP sample rebuilding the abandoned Star Wars API as a six-entity data model (Films, People, Planets, Species, Starships, Vehicles) chosen for its many-to-many, bi-directional relationships and its use as a Fiori Draft deep-editing test case. The author used CAP's OpenAPI functionality to generate both the Swagger UI test tool and entity diagrams for the data model, alongside the OData services and Fiori preview UI.published 2020-12-21
Adding a Swagger UI to Your SAP Cloud Application Programming Model / Node.js ServiceAdding a Swagger UI to Your SAP Cloud Application Programming Model / Node.js ServiceThe problem stated from the other side of the wire: a CAP and HANA backend consumed by frontend developers with no SAP background, who said in the first meeting that they could not work from what the service offered. A browsable API page is the answer, and this is the post the Swagger UI plugin indexed here exists to serve.published 2020-01-23
Adding a Swagger UI to Your SAP Cloud Application Programming Model / Node.js Service
cds-swagger-ui-express has been through 11 major lines since this was published, most recently 0.9 (2024-07), 0.10 (2024-10), 0.11 (2026-02). Affects Runnable code.
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Schema evolutioncapability, core and community
Data modellingcapability, core and community
SAP Communitypublishing source
SAP Communitycap-tag
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Type
blog
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community.sap.com
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History
- explains → applies_to on capability:data-modelling (cap)Door scope proposed from the title and summary, so a door page lists the piece only where it holds (docs/concepts/content-on-doors.md).
- Entered the atlasDiscovered via SAP Community · cap-tag.
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