PostgresSQL integration

[Kugelschieber]

Add Postgres as database backend. To do this, a new environment variable must be added, all SQL statements must be translated to Postgres and acweb must decide which one to use.

Example:
export ACWEB_DB_TYPE=postgres
In model/user.go:

import (
	// [...]
	// import os to read the env variable
	"os"
	// [...]
)
// [...]
// add database type specific SQL statements as constants
const (
	user_mysql_delete = "DELETE FROM user WHERE id = :id"
	user_postgres_delete = "DELETE FROM \"user\" WHERE id = $1"
)
// [...]
func (m *User) Remove() error {
	if m.Id == 0 {
		return errors.New("ID must be set")
	}

	// select the query by database type
	// os.Getenv("ACWEB_DB_TYPE") should be outsourced to make sure it's in lowercase
	// and there should be a check on startup a known DB type is set
	var sql string

	if os.Getenv("ACWEB_DB_TYPE") == "mysql" {
		sql = user_mysql_delete
	} else {
		sql = user_postgres_delete
	}

	_, err := session.NamedExec(sql, m)
	return err
}

The main difference between MySQL and Postgres is that table names in Postgres must be surrounded by quotes and variables are passed by $1, $2, ... $n instead of a :name.

[Kugelschieber]

Implemented.