Go

This guide describes how to create a SerenDB project and connect to it from a Go (Golang) application using pgx, a high-performance and feature-rich PostgreSQL driver for Go.

You'll learn how to connect to your SerenDB database from a Go application, and perform basic Create, Read, Update, and Delete (CRUD) operations.

Prerequisites

Create a SerenDB project

If you do not have one already, create a SerenDB project.

  1. Navigate to the Projects page in the SerenDB Console.

  2. Click New Project.

  3. Specify your project settings and click Create Project.

Your project is created with a ready-to-use database named neondb. In the following steps, you will connect to this database from your Go application.

Create a Go project

For your Go project, create a project directory, initialize a Go module, and add the required libraries.

  1. Create a project directory and change into it.

    mkdir neon-go-quickstart
cd neon-go-quickstart

    Open the directory in your preferred code editor (e.g., VS Code, GoLand).

  2. Initialize a Go module. This command creates a go.mod file to track your project's dependencies.

    go mod init neon-go-quickstart

  3. Add the required Go packages using go get.

    • pgx/v5: The database driver for connecting to Postgres.

    • godotenv: A helper library to manage environment variables from a .env file.

    go get github.com/jackc/pgx/v5 github.com/joho/godotenv

    This will download the packages and add them to your go.mod and go.sum files.

Store your SerenDB connection string

Create a file named .env in your project's root directory. This file will securely store your database connection string.

  1. In the SerenDB Console, select your project on the Dashboard.

  2. Click Connect on your Project Dashboard to open the Connect to your database modal. Connection modal

  3. Copy the connection string, which includes your password.

  4. Add the connection string to your .env file as shown below.

    DATABASE_URL="postgresql://[user]:[password]@[seren_hostname]/[dbname]?sslmode=require&channel_binding=require"

    Replace [user], [password], [seren_hostname], and [dbname] with your actual database credentials.

Examples

This section provides example Go scripts that demonstrate how to connect to your SerenDB database and perform basic operations such as creating a table, reading data, updating data, and deleting data.

Create a table and insert data

In your project directory, create a file named create_table.go. This script connects to your SerenDB database, creates a table named books, and inserts some sample data into it.

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/jackc/pgx/v5"
	"github.com/joho/godotenv"
)

func main() {
	// Load environment variables from .env file
	err := godotenv.Load()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error loading .env file: %v\n", err)
		os.Exit(1)
	}

	// Get the connection string from the environment variable
	connString := os.Getenv("DATABASE_URL")
	if connString == "" {
		fmt.Fprintf(os.Stderr, "DATABASE_URL not set\n")
		os.Exit(1)
	}

	ctx := context.Background()

	// Connect to the database
	conn, err := pgx.Connect(ctx, connString)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to connect to database: %v\n", err)
		os.Exit(1)
	}
	defer conn.Close(ctx)

	fmt.Println("Connection established")

	// Drop the table if it already exists
	_, err = conn.Exec(ctx, "DROP TABLE IF EXISTS books;")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to drop table: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("Finished dropping table (if it existed).")

	// Create a new table
	_, err = conn.Exec(ctx, `
        CREATE TABLE books (
            id SERIAL PRIMARY KEY,
            title VARCHAR(255) NOT NULL,
            author VARCHAR(255),
            publication_year INT,
            in_stock BOOLEAN DEFAULT TRUE
        );
    `)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to create table: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("Finished creating table.")

	// Insert a single book record
	_, err = conn.Exec(ctx,
		"INSERT INTO books (title, author, publication_year, in_stock) VALUES ($1, $2, $3, $4);",
		"The Catcher in the Rye", "J.D. Salinger", 1951, true,
	)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to insert single row: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("Inserted a single book.")

	// Data to be inserted
	booksToInsert := [][]interface{}{
		{"The Hobbit", "J.R.R. Tolkien", 1937, true},
		{"1984", "George Orwell", 1949, true},
		{"Dune", "Frank Herbert", 1965, false},
	}

	// Use CopyFrom for efficient bulk insertion
	copyCount, err := conn.CopyFrom(
		ctx,
		pgx.Identifier{"books"},
		[]string{"title", "author", "publication_year", "in_stock"},
		pgx.CopyFromRows(booksToInsert),
	)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to copy rows: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("Inserted %d rows of data.\n", copyCount)
}

The above code does the following:

  • Loads the connection string from the .env file using the godotenv library.

  • Connects to the SerenDB database using pgx.Connect. The defer conn.Close(ctx) statement ensures the connection is closed when the main function exits.

  • Uses conn.Exec to run SQL commands that don't return rows, such as DROP TABLE and CREATE TABLE.

  • Inserts a single row using conn.Exec with parameterized query placeholders ($1, $2, etc.) to prevent SQL injection.

  • Uses conn.CopyFrom for efficient bulk insertion of multiple records.

Run the script using the following command:

go run create_table.go

When the code runs successfully, it produces the following output:

Connection established
Finished dropping table (if it existed).
Finished creating table.
Inserted a single book.
Inserted 3 rows of data.

Read data

In your project directory, create a file named read_data.go. This script connects to your SerenDB database and retrieves all rows from the books table.

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/jackc/pgx/v5"
	"github.com/joho/godotenv"
)

func main() {
	err := godotenv.Load()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error loading .env file: %v\n", err)
		os.Exit(1)
	}

	connString := os.Getenv("DATABASE_URL")
	if connString == "" {
		fmt.Fprintf(os.Stderr, "DATABASE_URL not set\n")
		os.Exit(1)
	}

	ctx := context.Background()
	conn, err := pgx.Connect(ctx, connString)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to connect to database: %v\n", err)
		os.Exit(1)
	}
	defer conn.Close(ctx)
	fmt.Println("Connection established")

	// Fetch all rows from the books table
	rows, err := conn.Query(ctx, "SELECT * FROM books ORDER BY publication_year;")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Query failed: %v\n", err)
		os.Exit(1)
	}
	defer rows.Close()

	fmt.Println("\n--- Book Library ---")
	for rows.Next() {
		var id, publicationYear int
		var title, author string
		var inStock bool

		err := rows.Scan(&id, &title, &author, &publicationYear, &inStock)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Failed to scan row: %v\n", err)
			os.Exit(1)
		}
		fmt.Printf("ID: %d, Title: %s, Author: %s, Year: %d, In Stock: %t\n",
			id, title, author, publicationYear, inStock)
	}
	fmt.Println("--------------------\n")

	if err := rows.Err(); err != nil {
		fmt.Fprintf(os.Stderr, "Error during rows iteration: %v\n", err)
		os.Exit(1)
	}
}

The above code does the following:

  • Connects to the database using the connection string from the .env file.

  • Uses conn.Query to execute a SELECT statement, which returns a pgx.Rows object.

  • Iterates through the rows using rows.Next().

  • Uses rows.Scan() to copy the column values from the current row into Go variables.

  • Prints each book's details in a formatted output.

  • Checks for any errors that occurred during row iteration with rows.Err().

Run the script using the following command:

go run read_data.go

When the code runs successfully, it produces the following output:

Connection established

--- Book Library ---
ID: 2, Title: The Hobbit, Author: J.R.R. Tolkien, Year: 1937, In Stock: true
ID: 3, Title: 1984, Author: George Orwell, Year: 1949, In Stock: true
ID: 1, Title: The Catcher in the Rye, Author: J.D. Salinger, Year: 1951, In Stock: true
ID: 4, Title: Dune, Author: Frank Herbert, Year: 1965, In Stock: false
--------------------

Update data

In your project directory, create a file named update_data.go. This script connects to your SerenDB database and updates the stock status of the book 'Dune' to true.

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/jackc/pgx/v5"
	"github.com/joho/godotenv"
)

func main() {
	err := godotenv.Load()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error loading .env file: %v\n", err)
		os.Exit(1)
	}

	connString := os.Getenv("DATABASE_URL")
	if connString == "" {
		fmt.Fprintf(os.Stderr, "DATABASE_URL not set\n")
		os.Exit(1)
	}

	ctx := context.Background()
	conn, err := pgx.Connect(ctx, connString)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to connect to database: %v\n", err)
		os.Exit(1)
	}
	defer conn.Close(ctx)
	fmt.Println("Connection established")

	// Update a data row in the table
	_, err = conn.Exec(ctx, "UPDATE books SET in_stock = $1 WHERE title = $2;", true, "Dune")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Update failed: %v\n", err)
		os.Exit(1)
	}

	fmt.Println("Updated stock status for 'Dune'.")
}

The above code uses conn.Exec with a parameterized UPDATE statement to change the in_stock status of the book 'Dune'.

Run the script using the following command:

go run update_data.go

After running this script, you can run read_data.go again to verify that the row was updated.

go run read_data.go

When the code runs successfully, it produces the following output:

Connection established

--- Book Library ---
ID: 2, Title: The Hobbit, Author: J.R.R. Tolkien, Year: 1937, In Stock: true
ID: 3, Title: 1984, Author: George Orwell, Year: 1949, In Stock: true
ID: 1, Title: The Catcher in the Rye, Author: J.D. Salinger, Year: 1951, In Stock: true
ID: 4, Title: Dune, Author: Frank Herbert, Year: 1965, In Stock: true
--------------------

You can see that the stock status for 'Dune' has been updated to true.

Delete data

In your project directory, create a file named delete_data.go. This script connects to your SerenDB database and deletes the book '1984' from the books table.

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/jackc/pgx/v5"
	"github.com/joho/godotenv"
)

func main() {
	err := godotenv.Load()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error loading .env file: %v\n", err)
		os.Exit(1)
	}

	connString := os.Getenv("DATABASE_URL")
	if connString == "" {
		fmt.Fprintf(os.Stderr, "DATABASE_URL not set\n")
		os.Exit(1)
	}

	ctx := context.Background()
	conn, err := pgx.Connect(ctx, connString)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to connect to database: %v\n", err)
		os.Exit(1)
	}
	defer conn.Close(ctx)
	fmt.Println("Connection established")

	// Delete a data row from the table
	_, err = conn.Exec(ctx, "DELETE FROM books WHERE title = $1;", "1984")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Delete failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("Deleted the book '1984' from the table.")
}

The above code uses conn.Exec with a parameterized DELETE statement to remove the book '1984' from the books table.

Run the script using the following command:

go run delete_data.go

After running this script, you can run read_data.go again to verify that the row was deleted.

go run read_data.go

When the code runs successfully, it produces the following output:

Connection established

--- Book Library ---
ID: 2, Title: The Hobbit, Author: J.R.R. Tolkien, Year: 1937, In Stock: true
ID: 1, Title: The Catcher in the Rye, Author: J.D. Salinger, Year: 1951, In Stock: true
ID: 4, Title: Dune, Author: Frank Herbert, Year: 1965, In Stock: true
--------------------

You can see that the book '1984' has been successfully deleted from the books table.

Next steps: Using an ORM or framework

While this guide demonstrates how to connect to SerenDB using raw SQL queries, for more advanced and maintainable data interactions in your Go applications, consider using an Object-Relational Mapping (ORM) framework. ORMs not only let you work with data as objects but also help manage schema changes through automated migrations keeping your database structure in sync with your application models.

Explore the following resources to learn how to integrate ORMs with SerenDB:

Source code

You can find the source code for the application described in this guide on GitHub.

Get started with Go and SerenDB using pgx

Resources

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