Apache H2 Database Go Driver

This driver is VERY experimental state

NOT use for production yet

Introduction

Apache H2 Database is a very-low footprint database with in-memory capabilities.

It's written in Java and it's fully ACID compliant.

You can use H2 as embedded database or via TCP/IP.

It has interfaces for Postgres protocol and native TCP server.

Motivation

Until now, using H2 in your Go projects could only be done through the Postgres driver.

This approach has several cons. The poor error messagens or not being able to use native data types are some of them.

This pure Go driver uses the native TCP interface.

Pre-requesites

In "contrib" folder you can find the scripts to download and launch the H2 database server. You need to have any Java Runtime installed.

cd contrib
./downloadH2.sh
./runStandalone.sh

Usage

First make sure the H2 server is running in TCP server mode. You can launch using the runStandalone.sh or with a command similar to the following:

java -classpath h2.jar org.h2.tools.Server -tcp -tcpAllowOthers -ifNotExists

This starts the server at the defaulr port (9092)

The following example connect to H2 and creates an in-memory database.

package main

import (
	"database/sql"
	"log"
	_ "github.com/jmrobles/h2go"
)

func main() {
	conn, err := sql.Open("h2", "h2://sa@localhost/testdb?mem=true")
	if err != nil {
		log.Fatalf("Can't connet to H2 Database: %s", err)
	}
    err = conn.Ping()
    if err != nil {
        log.Fatalf("Can't ping to H2 Database: %s", err)
    }
    log.Printf("H2 Database connected")
    conn.Close()
}

In the folder examples you can find more examples.

Connection string

In the connection string you must specify:

• Database driver: h2 literal
• Username (optional)
• Password (optinal)
• Host: format (:)?
• Database name
• Other connection options

Options

You can use the following options:

• mem=(true|false): to use in-memory or in-disk database
• logging=(none|info|debug|error|warn|panic|trace): the common logging level

Parameters

For the use of parameters in SQL statement you need to use the ? placeholder symbol.

For example:

    conn.Exec("INSERT INTO employees VALUES (?,?,?)", name, age, salary)

Data types

The following H2 datatypes are implemented:

H2 Data type	Go mapping
String	string
StringIgnoreCase	string
StringFixed	string
Bool	bool
Short	int16
Int	int32
Long	int64
Float	float32
Double	float64
Byte	byte
Bytes	[]byte
Time	time.Time
Time with timezone	time.Time
Date	time.Time
Timestamp	time.Time
Timestamp with timezone	time.Time

H2 Supported version

This driver supports H2 database version 1.4.200 or above.

ToDo

• Rest of native data types (UUID, JSON, Decimal, ...)
• NamedValue interface
• Multiple result sets
• Improve context usage (timeouts, ...)
• Submit your issue

Contributors

jmrobles

Pull Requests are welcome

License

MIT License