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添加 SQLDelight 并编写 .sq 模式

定义数据表并生成类型安全的 Kotlin API

添加 SQLDelight 并编写 .sq 模式 是 CoddyKit 上的免费 Kotlin Multiplatform Academy 课时。这是第 1 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Kotlin Multiplatform Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Kotlin Multiplatform Academy 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

Meet SQLDelight

SQLDelight turns your SQL into type-safe Kotlin you can call from shared code. You write real SQL, it writes the boilerplate. 🗄️

Why It Fits KMP

Because it generates plain Kotlin from SQL, the same database code runs on Android and iOS. The queries are shared, the engine is native per platform.

Add the Gradle Plugin

You enable SQLDelight by adding its Gradle plugin to your shared module so it can scan and process your schema files.

plugins {
    id("app.cash.sqldelight") version "2.0.2"
}

Add the Runtime

The plugin generates code, but you also need the runtime dependency in commonMain so the generated queries actually execute.

commonMain.dependencies {
    implementation("app.cash.sqldelight:runtime:2.0.2")
}

Declare a Database

You tell SQLDelight the database name and where it lives. This databases block names the generated class you will use later.

sqldelight {
    databases {
        create("AppDatabase") {
            packageName.set("com.example.db")
        }
    }
}

What Is a .sq File

Your schema lives in .sq files: plain text holding SQL statements plus named queries. SQLDelight reads them and emits Kotlin.

Where .sq Files Go

Place .sq files under commonMain/sqldelight in the package you declared. The plugin only looks there for your schema.

commonMain/sqldelight/com/example/db/Player.sq

Define a Table

Inside a .sq file you write a normal CREATE TABLE statement. SQLDelight uses it to type-check every query you write.

CREATE TABLE player (
    id INTEGER NOT NULL PRIMARY KEY,
    name TEXT NOT NULL
);

Name Your Queries

Each query starts with a label ending in a colon. SQLDelight turns that label into a Kotlin function you can call.

selectAll:
SELECT * FROM player;

Parameters Become Arguments

A ? placeholder in SQL becomes a typed Kotlin function parameter, so the compiler checks your inputs for you.

selectById:
SELECT * FROM player WHERE id = ?;

Generated Type Safety

SQLDelight maps your columns to Kotlin types. A wrong column or type is caught at compile time, not at runtime in production.

Quick Check

Where do your SQLDelight schema files belong in a KMP project?

Recap: Schema First

You added the plugin and runtime, declared a database, and wrote a .sq schema with named queries. Next you give each platform a driver. ✅

常见问题解答

「添加 SQLDelight 并编写 .sq 模式」课时是免费的吗？

是的 — 「添加 SQLDelight 并编写 .sq 模式」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Kotlin Multiplatform Academy 课程的其余内容，请升级到 CoddyKit PRO。 Kotlin Multiplatform Academy 课程共包含 4 节课。

「添加 SQLDelight 并编写 .sq 模式」这节课中我会学到什么？

定义数据表并生成类型安全的 Kotlin API 你通过在浏览器中直接运行的动手代码来练习 Kotlin Multiplatform Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Kotlin Multiplatform Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Kotlin Multiplatform Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 1 节课，共 4 节。

「添加 SQLDelight 并编写 .sq 模式」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Kotlin Multiplatform Academy 课中编写并运行代码吗？

能。每节 Kotlin Multiplatform Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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