Errors & Debugging

import {
  DatabaseError,
  ValidationError,
  ConstraintViolationError,
  NotFoundError,
  isDatabaseError,
  hasErrorCode,
} from "@b9g/zen";

// Validation errors (Zod / Standard Schema)
try {
  await db.insert(Users, {email: "not-an-email"});
} catch (e) {
  if (hasErrorCode(e, "VALIDATION_ERROR")) {
    console.log(e.fieldErrors); // {email: ["Invalid email"]}
  }
}

// Constraint violations (database-level)
try {
  await db.insert(Users, {id: "1", email: "duplicate@example.com"});
} catch (e) {
  if (e instanceof ConstraintViolationError) {
    console.log(e.kind);       // "unique"
    console.log(e.constraint); // "users_email_unique"
    console.log(e.table);      // "users"
    console.log(e.column);     // "email"
  }
}

// Transaction errors are rolled back automatically
await db.transaction(async (tx) => {
  await tx.insert(Users, newUser);
  await tx.insert(Posts, newPost); // fails -> whole transaction rolled back
});

// Print SQL without executing
const query = db.print`SELECT * FROM ${Posts} WHERE ${Posts.cols.published} = ${true}`;
console.log(query.sql);    // SELECT * FROM "posts" WHERE "posts"."published" = ?
console.log(query.params); // [true]

// Debug fragments
console.log(Posts.set({title: "Updated"}).toString());
// SQLFragment { sql: "\"title\" = ?", params: ["Updated"] }

// Query execution plan
await db.explain`SELECT * FROM ${Posts}`;