Queries da mutations da subscriptions a cikin GraphQL?

Question

IT Interview Practice · Accepted Answer

Su ne nau'ikan **operation** guda uku, kowanne an tsara shi zuwa wani root type a cikin schema:

- **Query** — yana karanta bayanai. Filaye suna gudana **a layi ɗaya (in parallel)** kuma dole ba su da wani sakamako na gefe (kamar HTTP GET).
- **Mutation** — yana rubuta bayanai (ƙirƙira/sabuntawa/gogewa). Filayen top-level suna gudana **jere (sequentially)**, don haka an tabbatar da tsari.
- **Subscription** — rafi mai dorewa (long-lived): uwar garke tana turawa abokin ciniki sabbin bayanai ta wata hanya kamar WebSockets duk lokacin da wani abu ya faru.

```graphql
query GetPost {              # read
  post(id: "1") { title }
}

mutation AddComment {        # write; returns the created object so the client updates its cache
  addComment(postId: "1", text: "Nice!") {
    id
    text
  }
}

subscription OnComment {     # live: fires every time a comment is added
  commentAdded(postId: "1") {
    id
    text
  }
}
```

Mutations suna ɗaukar **arguments** (galibi object na `input`) kuma ya kamata su **mayar da bayanan da abin ya shafa** don abokin ciniki ya iya sabuntawa ba tare da buƙata ta biyu ba. Ƙa'idar jere tana da muhimmanci: mutations biyu a cikin takarda ɗaya — `deposit` sannan `withdraw` — kullum suna gudana a wannan tsari, alhalin filayen tambaya biyu na iya warware su a lokaci guda.

## Me ya sa yake da muhimmanci

Masu tambayoyin hira suna duba ko ka san cewa **queries suna a layi ɗaya kuma ba su da sakamako na gefe alhalin mutations suna jere**, kuma cewa subscription na buƙatar hanya mai riƙe da yanayi (WebSocket/SSE). Mayar da bayanai da aka sabunta daga mutation shi ne cikakken bayanin da yake raba mutanen da suka aiko GraphQL da waɗanda kawai suka karanta game da shi.

Me ya sa yake da muhimmanci

Tambayoyi masu alaƙa