simdb a simple json db in GO

Some days ago I decided to learn GO. GO is pretty easy to learn and could learn syntax and semantics in couple of hours. To completely learn a language I normally write a small app in that language. So in my free time, I rewrote the expense service created in nodejs to GO and is now live and we are using it. This whole exercise allow me to learn GO in detail.

For me GO looks to be a great simple language with static type checking. Seems like I will be using GO for my future RPi projects than nodejs. In RPi more often I use a simple json as a db to store, retrieve and update execution rules, Sensor details, etc. In nodejs I use tingodb, couldn’t find some thing very similar in GO, so decided to write one, and is called simdb, a simple json db.

Using simdb I can persist stuct or retrieve or update or delete them from the json db. The db file created by simdb is a simple json file. Let’s see some of the functions in simdb.

Create a new instance of db

driver, err:=db.New("customer")

Insert a new Customer to db

    customer:=Customer {
        CustID:"CUST1",
        Name:"sarouje",
        Address: "address",
        Contact: Contact {
            Phone:"45533355",
            Email:"someone@gmail.com",
        },
    }
    
    err=driver.Insert(customer)
    if(err!=nil){
        panic(err)
    }

Get a Customer

    var customerFirst Customer
    err=driver.Open(Customer{}).Where("custid","=","CUST1").First().AsEntity(&customerFirst)
    if(err!=nil){
        panic(err)
    }

Update a customer

    customerFirst.Name="Sony Arouje"
    err=driver.Update(customerFirst)
    if(err!=nil){
        panic(err)
    }

Delete a customer

    toDel:=Customer{
        CustID:"CUST1",
    }
    err=driver.Delete(toDel)
    if(err!=nil){
        panic(err)
    }

Update and Delete operation uses the ID field of the struct to perform it’s operation.

Let’s see the full code.

package main

import (
    "github.com/sonyarouje/simdb/db"
    "fmt"
)

type Customer struct {
    CustID string `json:"custid"`
    Name string `json:"name"`
    Address string `json:"address"`
    Contact Contact
}

type Contact struct {
    Phone string `json:"phone"`
    Email string `json:"email"`
}
//ID any struct that needs to persist should implement this function defined 
//in Entity interface.
func (c Customer) ID() (jsonField string, value interface{}) {
    value=c.CustID
    jsonField="custid"
    return
}

func main(){
    fmt.Println("starting....")

    driver, err:=db.New("dbs")

    if(err!=nil){
        panic(err)
    }

    customer:=Customer {
        CustID:"CUST1",
        Name:"sarouje",
        Address: "address",
        Contact: Contact {
            Phone:"45533355",
            Email:"someone@gmail.com",
        },
    }
    //creates a new Customer file inside the directory passed as the 
    //parameter to New(). If the Customer file already exist 
    //then insert operation will add the customer data to the array
    err=driver.Insert(customer)
    if(err!=nil){
        panic(err)
    }
    
    //GET ALL Customer
    //opens the customer json file and filter all the customers with name sarouje.
    //AsEntity takes an address to Customer array and fills the result to it.
    //we can loop through the customers array and retireve the data.
    var customers []Customer
    err=driver.Open(Customer{}).Where("name","=","sarouje").Get().AsEntity(&customers)
    if(err!=nil){
        panic(err)
    }
    // fmt.Printf("%#v \n", customers)
    
    //GET ONE Customer
    //First() will return the first record from the results 
    //AsEntity takes the address to Customer variable (not an array pointer)
    var customerFirst Customer
    err=driver.Open(Customer{}).Where("custid","=","CUST1").First().AsEntity(&customerFirst)
    if(err!=nil){
        panic(err)
    }
    
    //Update function uses the ID() to get the Id field/value to find the record and update the data.
    customerFirst.Name="Sony Arouje"
    err=driver.Update(customerFirst)
    if(err!=nil){
        panic(err)
    }
    driver.Open(Customer{}).Where("custid","=","CUST1").First().AsEntity(&customerFirst)
    fmt.Printf("%#v \n", customerFirst)

    // Delete
    toDel:=Customer{
        CustID:"CUST1",
    }
    err=driver.Delete(toDel)
    if(err!=nil){
        panic(err)
    }
}

TODO

The query syntax in simdb is not really great, I need to find a better approach.

Source Code: https://github.com/sonyarouje/simdb

Written by Sony Arouje

August 6, 2018 at 2:30 pm

Posted in GO

Tagged with db, GO, golang, json

Sony Arouje