peterbamuhigire/android-room

Android Room Database

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Use When

• Comprehensive Room database skill for Android — entities, DAOs, relations, migrations, conflict resolution, FTS4, views, paging, SQLCipher, and testing. Built from Mark Murphy's "Elements of Android Room". Use alongside android-data-persistence for full offline-first architecture.
• The task needs reusable judgment, domain constraints, or a proven workflow rather than ad hoc advice.

Do Not Use When

• The task is unrelated to android-room or would be better handled by a more specific companion skill.
• The request only needs a trivial answer and none of this skill's constraints or references materially help.

Required Inputs

• Gather relevant project context, constraints, and the concrete problem to solve.
• Confirm the desired deliverable: design, code, review, migration plan, audit, or documentation.

Workflow

• Read this SKILL.md first, then load only the referenced deep-dive files that are necessary for the task.
• Apply the ordered guidance, checklists, and decision rules in this skill instead of cherry-picking isolated snippets.
• Produce the deliverable with assumptions, risks, and follow-up work made explicit when they matter.

Quality Standards

• Keep outputs execution-oriented, concise, and aligned with the repository's baseline engineering standards.
• Preserve compatibility with existing project conventions unless the skill explicitly requires a stronger standard.
• Prefer deterministic, reviewable steps over vague advice or tool-specific magic.

Anti-Patterns

• Treating examples as copy-paste truth without checking fit, constraints, or failure modes.
• Loading every reference file by default instead of using progressive disclosure.

Outputs

• A concrete result that fits the task: implementation guidance, review findings, architecture decisions, templates, or generated artifacts.
• Clear assumptions, tradeoffs, or unresolved gaps when the task cannot be completed from available context alone.
• References used, companion skills, or follow-up actions when they materially improve execution.

References

• Use the links and companion skills already referenced in this file when deeper context is needed.

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1. Overview

Three core components:

@Entity (data classes) → @Dao (SQL + suspend/Flow) → @Database (registry + builder)
        ↓                          ↑
   TypeConverters          @Transaction wrappers

Room generates SQLite boilerplate at compile time via KSP. All writes are suspend; reactive reads return Flow.

2. Gradle Dependencies

val roomVersion = "2.6.1"
implementation("androidx.room:room-runtime:$roomVersion")
implementation("androidx.room:room-ktx:$roomVersion")
ksp("androidx.room:room-compiler:$roomVersion")           // KSP, NOT kapt
implementation("androidx.room:room-paging:$roomVersion")  // optional, Paging 3
testImplementation("androidx.room:room-testing:$roomVersion")
testImplementation("app.cash.turbine:turbine:1.1.0")      // Flow testing
// Plugin: id("com.google.devtools.ksp") version "2.0.0-1.0.21"
// Schema: ksp { arg("room.schemaLocation", "$projectDir/schemas") }

Additional Guidance

Extended guidance for android-room was moved to references/skill-deep-dive.md to keep this entrypoint compact and fast to load.

Use that deep dive for:

• 3. Entities
• 4. TypeConverters
• 5. DAOs
• 6. Database Class
• 7. Relations
• 8. Transactions
• 9. Conflict Resolution
• 10. Migrations
• 11. Full-Text Search (FTS4)
• 12. Database Views
• 13. Paging 3
• 14. Pre-Populated Databases
• Additional deep-dive sections continue in the reference file.