moved study stuff

Study/AppSync/GraphQL.md

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+# GraphQL
+GraphQL is an FOSS agnostic query adaptor that allows you to query data from many different data sources. GraphQL is used to build APIs where clients will send a query for nested data. GraphQL mitigates the issue of versioned or rapidly changing APIs compared to REST APIs because you can request the data you want.
+
+GraphQL schemas are written in the GraphQL SDL (Schema Definition Language) composed on:
+- **Types**. Represent objects and their **fields**:
+```graphql
+type Query {
+    me: User
+}
+
+type User {
+    id: ID
+    name: String
+}
+```
+- **Fields**
+- **Queries**. Define the exact shape of the data needed by the client:
+```graphql
+query CurrentUser {
+    currentUser {
+        name
+        age
+    }
+}
+```
+- **Mutations**. Allow for data to be create, updated or deleted:
+```graphql
+mutation CreateUser($name: String!, $age: Int!) {
+    createUser(userName: $name, age: $age) {
+        name
+        age
+    }
+}
+```
+- **Subscriptions**. Supports live updates sent from the server to the client:
+```graphql
+subscription {
+    newPerson {
+        name
+        age
+    }
+}
+```

Study/AppSync/_AppSync.md

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+# AppSync
+AppSync is a fully managed [[GraphQL|GraphQL]] service.
+
+Notes:
+- It can support real-time [[API]]s via GraphQL subscriptions.
+- AppSync supports custom domains
+- AppSync has a query editor built into the UI
+
+## Resolvers
+Resolvers attached to specific fields within your types in your schema. used to implement the state-changing operations for your query, mutation, and subscription field operations.
+
+Runtimes:
+- **`APPSYNC_JS`**: JavaScript
+- **VTL**: Velocity Template Language.
+
+## Data Sources
+Where data is being pulled from.
+
+- DynamoDB Table
+- Amazon OpenSearch
+- AWS [[_Lambda|Lambda Function]]
+- [[HTTP]] Endpoint
+- Amazon EventBridge
+- Relational Database (RDS HTTP Endpoint)
+
+## API Types
+- **GraphQL APIs** - single API from multiple data sources
+- **Merged APIs** - a collection of Graph APIs that act as one API
+    - Useful if you have multiple teams that manage their own API but you want to treat all the APIs as a single API.
+ 
+## Caching Options
+- **None**: Self explanatory; no caching, resolvers will always fetch from data sources.
+- **Full request caching**: Self explanatory; caches all requests.
+- **Per-resolver caching**: specific operation or field defined in a resolver will return responses from the cache.
+Caching isn't serverless; you must provision an on-demand instance.
+
+# Authorisation
+- API Key
+- AWS IAM
+- Cognito User Pools
+
+
+
+