插入、查询和更新行
从共享代码执行 CRUD 操作
插入、查询和更新行 是 CoddyKit 上的免费 Kotlin Multiplatform Academy 课时。 这是第 3 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。
Reach the Generated Queries
Your database exposes a queries object named after the .sq file. Every labeled statement becomes a method on it.
val queries = database.playerQueriesWrite an Insert Query
Add an insert label in your .sq file. SQLDelight turns its placeholders into typed Kotlin parameters.
insertPlayer:
INSERT INTO player(id, name) VALUES (?, ?);Call Insert from Kotlin
Now you call the generated function with real values. The types are checked, so a wrong argument fails to compile.
queries.insertPlayer(id = 1, name = "Ada")Select All Rows
Run a select query and ask for executeAsList to get every matching row as a typed Kotlin list.
val players = queries.selectAll().executeAsList()Mapped to Data Classes
SQLDelight maps each row to a generated data class with named, typed properties, so you avoid string-keyed cursors.
players.forEach { println(it.name) }Select a Single Row
For a one-row query use executeAsOneOrNull, which returns null instead of crashing when nothing matches.
val player = queries.selectById(1).executeAsOneOrNull()Write an Update Query
An update label changes existing rows. Put the new value first and the matching key last as placeholders.
updateName:
UPDATE player SET name = ? WHERE id = ?;Call Update from Kotlin
Invoke the generated update like any function. SQLDelight runs the SQL and applies it to every matching row.
queries.updateName(name = "Grace", id = 1)Delete Rows
A delete query removes rows by condition. Without a WHERE clause it clears the whole table, so be careful.
deleteById:
DELETE FROM player WHERE id = ?;Group with Transactions
Wrap several writes in a transaction so they all succeed or all roll back together, keeping your data consistent.
queries.transaction {
queries.insertPlayer(2, "Linus")
queries.insertPlayer(3, "Margaret")
}Runs the Same Everywhere
Because the queries are shared, this exact CRUD code behaves identically on Android and iOS. Write it once, trust it twice.
Quick Check
You query for one player by id but it may not exist. Which call is safest?
Recap: Full CRUD
You inserted, selected, updated and deleted rows with type-safe generated queries and grouped writes in a transaction. Next, make it reactive. ✅
常见问题解答
「插入、查询和更新行」课时是免费的吗？
是的 — 「插入、查询和更新行」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。
「插入、查询和更新行」这节课中我会学到什么？
从共享代码执行 CRUD 操作 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 3 节课，共 4 节。
「插入、查询和更新行」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。