---
title: Type Utilities
description: Derive row, insert, and update types directly from schema.
---

# Type Utilities

`tsql` exports utility types that read from your schema.

```ts
import type { Insertable, Table, TableRow, Updatable } from "@bms/tsql";
import { schema } from "./schema";

type UserA = Table<typeof schema, "users">;
type UserB = TableRow<typeof schema, "users">;
type NewUser = Insertable<typeof schema, "users">;
type UserPatch = Updatable<typeof schema, "users">;
```

## Type meanings

- `Table` / `TableRow`: full table row shape
- `Insertable`: object accepted by `insert(...).values(...)`
- `Updatable`: object accepted by `update(...).set(...)`

`Insertable` and `Updatable` are intentionally permissive (`Partial`-style) to support partial writes and DB defaults.

## Expression types

- `Expr<T>`: typed SQL expression
- `OrderExpr`: ordering expression (`asc` / `desc`)

You usually consume these through query callbacks, but they are also useful in helper functions.

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Title: Type Utilities
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