Debug queries

These are the logging levels upper/db comes with, ranging from the lowest severity (trace) to the highest (panic).

db.LogLevelTrace
db.LogLevelDebug
db.LogLevelInfo
db.LogLevelWarn
db.LogLevelError
db.LogLevelFatal
db.LogLevelPanic

By default, upper/db is set to db.LogLevelWarn. Use db.LC() to set a different logging level:

db.LC().SetLevel(db.LogLevelDebug)

Set an appropriate logging level in production, as using levels lower than db.LogLevelWarn could make things pretty slow and verbose.

db.LC().SetLevel(db.LogLevelError)

Handle Errors

Error scenarios may or may not be fatal depending on the nature of your application, so make sure you’re handling them properly:

err = booksTable.Find(1).One(&book)
if err != nil {
  if errors.Is(err, db.ErrNoMoreRows) {
    // No rows found, which is okay.
    return nil
  }
  return err
}

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              package main

import (
	"fmt"
	"log"

	"github.com/upper/db/v4"
	"github.com/upper/db/v4/adapter/postgresql"
)

var settings = postgresql.ConnectionURL{
	Database: "booktown",
	Host:     "postgres",
	User:     "demo",
	Password: "demopass",
	Options: map[string]string{
		"sslmode": "disable", // Disable TLS
	},
}

// Book represents a record from the "books" table. This table has an integer
// primary key ("id"):
//
// booktown=> \d books
//
//	    Table "public.books"
//	Column   |  Type   | Modifiers
//
// ------------+---------+-----------
//
//	id         | integer | not null
//	title      | varchar | not null
//	author_id  | integer |
//	subject_id | integer |
//
// Indexes:
//
//	"books_id_pkey" PRIMARY KEY, btree (id)
//	"books_title_idx" btree (title)
type Book struct {
	ID        uint   `db:"id"`
	Title     string `db:"title"`
	AuthorID  uint   `db:"author_id"`
	SubjectID uint   `db:"subject_id"`
}

func main() {
	// Set logging level to DEBUG
	db.LC().SetLevel(db.LogLevelDebug)

	sess, err := postgresql.Open(settings)
	if err != nil {
		fmt.Println("ERROR: Could not establish a connection with database: %v.", err)
		log.Fatalf(`SUGGESTION: Set password to "b4dp4ss" and try again.`)
	}
	defer sess.Close()

	fmt.Printf("Connected to %q using %q\n", sess.Name(), sess.ConnectionURL())

	booksTable := sess.Collection("books")

	// Find looks for a record that matches the integer primary key of the
	// "books" table.
	var book Book
	err = booksTable.Find(1).One(&book)
	if err != nil {
		if err == db.ErrNoMoreRows {
			fmt.Printf("ERROR: %v\n", err)
			log.Fatalf("SUGGESTION: Change Find(1) into Find(4267).")
		} else {
			fmt.Printf("ERROR: %v", err)
		}
		log.Fatal("An error ocurred, cannot continue.")
	}

	fmt.Printf("Book: %#v", book)
}

            