Introduction to Database Programming

In this lesson, explore introduction to database programming through one small Go program, and connect its output to the language rules behind it.

A database stores application records beyond the lifetime of a single request. Go’s database/sql package supplies common interfaces for relational databases; a separate driver implements communication with a particular database system.

Identify a durable source of truth and model data carefully. The runnable example uses in-memory data to teach record lookup, not a SQL connection.

Follow this diagram before executing the example. Check where a value or decision changes what runs next.

Start with the official relational database tutorial. SQL lessons below show runnable concepts and separate actual database/sql snippets because a real driver and configured database cannot be assumed in an online compiler.

This example is a complete program. Save it as main.go or paste it into the Go Playground.

Go code

package main

import "fmt"

type Task struct {
	ID    int
	Title string
}

func main() {
	tasks := map[int]Task{1: {ID: 1, Title: "Learn SQL"}}
	task, ok := tasks[1]
	fmt.Println("Found:", ok, "Title:", task.Title)
}

Output

Found: true Title: Learn SQL

A map lookup retrieves one Task by ID while main runs. Unlike a database, the map is lost when the process exits.

• In-memory Go maps are not durable storage.
• A SQL driver is required for a real connection using database/sql.

Design a tasks SQL table with a primary key and a title field; compare its durability to this map.

Tip: Edit the example above, predict the output, and run the modified code to test your reasoning.

You have practiced Introduction to Database Programming in a small, self-contained program. The important habit is to predict what runs, inspect the actual output and distinguish the language rule from the particular example.

Before continuing, make sure you can explain the program to someone who has not seen it, including the line that changes its result.