Depending on your use cases you may need to access your databases which different patterns and technologies (CRUD+UI, batch, reactive, IoT, ...). At DataStax, the developer advocates team implements reference applications for developers. We had the chance to implement multiple approaches and can provide feedback. KillrVideo.com is one of this application, it has been written in 3 languages (Java, C# and Node) and implement API with REST, Grpc and GraphQL. Though live session, browsing real code, you will see implementation details, lessons learnt and get working source code in Github as takeaway.

1. 1
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
Design API for
your databases

2. 2
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
https://github.com/clun
https://fr.linkedin.com/in/clunven
@clunven
Cédrick Lunven
Developer Advocate @
About me

3. 3
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
Objectives
1. Provide you a working API implementing Rest, gRPC
and GraphQL
2. Give implementations details through Demo
3. Reveal hints to choose and WHY, (specially to work
with Databases)

4. 4
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
KillrVideo
http://dev.killrvideo.com
https://killrvideo.github.io/

5. 5
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
Data model design
Entities & Relationships
Queries

6. 6
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
Conceptual Data Model

7. 7
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
Application workflow
Q2: Find comments posted for a user with a known id
(show most recent first)
comments_by_video
comments_by_user
Q1: Find comments for a video with a known id
(show most recent first)
Q3: CRUD Operations

8. 8
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
Logical Data Model
userid
creationdate
commentid
videoid
comment
comments_by_user
K
C
↑
videoid
creationdate
commentid
userid
comment
comments_by_video
C
↑
K
C
↑
↑C

9. 9
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
Physical Data Model
userid
commentid
videoid
comment
comments_by_user
TIMEUUID
K
TEXT
C
UUID
UUID
↑
videoid
commentid
userid
comment
comments_by_video
TIMEUUID
K
TEXT
C
UUID
UUID
↑

10. 10
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
DDL Schema
CREATE TABLE IF NOT EXISTS comments_by_user (
userid uuid,
commentid timeuuid,
videoid uuid,
comment text,
PRIMARY KEY ((userid), commentid)
) WITH CLUSTERING ORDER BY (commentid DESC);
CREATE TABLE IF NOT EXISTS comments_by_video (
videoid uuid,
commentid timeuuid,
userid uuid,
comment text,
PRIMARY KEY ((videoid), commentid)
) WITH CLUSTERING ORDER BY (commentid DESC);

11. 11
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
Databases access patterns
Entities/Relationships
Mutations
Queries /
Functions
Paging
Sorting
Filtering
Caching
Sync vs Async
Atomicity
Reactive
Consistency
Level
Versioning, Performance, Latencies
Conceptual
Data Model
Application
Workflow

12. 12
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
Tools in Action
killrvideo-dse
Drivers
DAO
killrvideo-api-rest killrvideo-api-grpc killrvideo-api-graphql

13. 13
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
DEMO

14. 14
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
+ Resources Oriented
+ Decoupled client and server
+ API can evolve over time (versioning)
+ Reuse HTTP
 Mutations
 Create Read Update Delete
 Servlerless endpoints
- Big Payload
- Functions exposition
- No ad hoc discoverability

15. 15
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
+ Very large network of services
+ High Performance
+ Streaming
 High Performance
 Action/Function oriented API
 Streaming & Async
- Strongly Coupled
- No discoverability
- Function exposition

16. 16
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
+ Low network overhead
+ Typed schema
+ Relations
 Latencies matter (mobile)
 Service aggregation
 Nice for clients – caution for Server side
- Complexity
- Caching
- Versioning
- Still early
GraphQL

17. 17
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
Databases access patterns
Entities/Relationships
Mutations
Queries /
Functions
Conceptual
Data Model
Application
Workflow

18. 18
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices
 https://github.com/clun/voxxeddays-api

19. 19
Create API for your databases Rest, gRPC, GraphQL
@clunven | @vxdmicroservice | #microservices