Building a (CRUD) using MySQL and Golang.

In this example i am going to present an example program to learn and create a crud(Create, Read, Update and Delete) using go programming and MySQL.
It is also known as Rest API

Step 1: Import and prepare mysql driver into your project
Installing MySQL database driver for go lang for this run the following command:

$ go get -u github.com/go-sql-driver/mysql

After installing create the database for your crud app for example “gocrud”

Step 2: Creating a table for storing details of employees
for this you can use the following code:

CREATE TABLE `myemployee` (
  `id` int(6) unsigned NOT NULL AUTO_INCREMENT,
  `fullname` varchar(25) NOT NULL,
  `address` varchar(25) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1;

Step 3: Create a Struct, Handler and Handler Function
for this create a file for example main.go and use the downloading codes inside this file.

package main

import (
    "database/sql"
    "log"
    "net/http"
    "text/template"

    _ "github.com/go-sql-driver/mysql"
)

type Myemployee struct {
    Id    int
    Full_Name  string
    Address string
}

func dbConn() (db *sql.DB) {
    dbDriver := "mysql"
    dbUser := "root"
    dbPass := "root"
    dbName := "goblog"
    db, err := sql.Open(dbDriver, dbUser+":"+dbPass+"@/"+dbName)
    if err != nil {
        panic(err.Error())
    }
    return db
}

var tmpl = template.Must(template.ParseGlob("form/*"))

func Index(w http.ResponseWriter, r *http.Request) {
    db := dbConn()
    selDB, err := db.Query("SELECT * FROM Employee ORDER BY id DESC")
    if err != nil {
        panic(err.Error())
    }
    emp := Myemployee{}
    res := []Myemployee{}
    for selDB.Next() {
        var id int
        var fullname, address string
        err = selDB.Scan(&id, &name, &city)
        if err != nil {
            panic(err.Error())
        }
        emp.Id = id
        emp.Full_Name = fullname
        emp.Address = address
        res = append(res, emp)
    }
    tmpl.ExecuteTemplate(w, "Index", res)
    defer db.Close()
}

func Show(w http.ResponseWriter, r *http.Request) {
    db := dbConn()
    nId := r.URL.Query().Get("id")
    selDB, err := db.Query("SELECT * FROM Myemployee WHERE id=?", nId)
    if err != nil {
        panic(err.Error())
    }
    emp := Myemployee{}
    for selDB.Next() {
        var id int
        var fullname, address string
        err = selDB.Scan(&id, &fullname, &address)
        if err != nil {
            panic(err.Error())
        }
        emp.Id = id
        emp.Full_Name = fullname
        emp.Address = address
    }
    tmpl.ExecuteTemplate(w, "Show", emp)
    defer db.Close()
}

func New(w http.ResponseWriter, r *http.Request) {
    tmpl.ExecuteTemplate(w, "New", nil)
}

func Edit(w http.ResponseWriter, r *http.Request) {
    db := dbConn()
    nId := r.URL.Query().Get("id")
    selDB, err := db.Query("SELECT * FROM Myemployee WHERE id=?", nId)
    if err != nil {
        panic(err.Error())
    }
    emp := Myemployee{}
    for selDB.Next() {
        var id int
        var fullname, address string
        err = selDB.Scan(&id, &fullname, &address)
        if err != nil {
            panic(err.Error())
        }
        emp.Id = id
        emp.Full_Name = fullname
        emp.Address = address
    }
    tmpl.ExecuteTemplate(w, "Edit", emp)
    defer db.Close()
}

func Insert(w http.ResponseWriter, r *http.Request) {
    db := dbConn()
    if r.Method == "POST" {
        fullname := r.FormValue("fullname")
        address:= r.FormValue("address")
        insForm, err := db.Prepare("INSERT INTO Myemployee(fullname, address) VALUES(?,?)")
        if err != nil {
            panic(err.Error())
        }
        insForm.Exec(name, city)
        log.Println("INSERT: FullName: " + fullname + " | Address: " + address)
    }
    defer db.Close()
    http.Redirect(w, r, "/", 301)
}

func Update(w http.ResponseWriter, r *http.Request) {
    db := dbConn()
    if r.Method == "POST" {
        fullname := r.FormValue("fullname")
        address:= r.FormValue("address")
        id := r.FormValue("uid")
        insForm, err := db.Prepare("UPDATE Myemployee SET firstname=?, address=? WHERE id=?")
        if err != nil {
            panic(err.Error())
        }
        insForm.Exec(fullname, address, id)
        log.Println("UPDATE: FullName: " + fullname + " | Address: " + address)
    }
    defer db.Close()
    http.Redirect(w, r, "/", 301)
}

func Delete(w http.ResponseWriter, r *http.Request) {
    db := dbConn()
    emp := r.URL.Query().Get("id")
    delForm, err := db.Prepare("DELETE FROM Myemployee WHERE id=?")
    if err != nil {
        panic(err.Error())
    }
    delForm.Exec(emp)
    log.Println("DELETE")
    defer db.Close()
    http.Redirect(w, r, "/", 301)
}

func main() {
    log.Println("Server started on: http://localhost:8080")
    http.HandleFunc("/", Index)
    http.HandleFunc("/show", Show)
    http.HandleFunc("/new", New)
    http.HandleFunc("/edit", Edit)
    http.HandleFunc("/insert", Insert)
    http.HandleFunc("/update", Update)
    http.HandleFunc("/delete", Delete)
    http.ListenAndServe(":8080", nil)
}

Step 4: Now create template files
For further processing you will need to create template files for your CRUD application.
for this lets create a template file named Index.tmpl and put the following code:

{{ define "Index" }}
  {{ template "Header" }}
    {{ template "Menu"  }}
    <h2> Registered </h2>
    <table border="1">
      <thead>
      <tr>
        <td>ID</td>
        <td>Full Name</td>
        <td>Address</td>
        <td>View</td>
        <td>Edit</td>
        <td>Delete</td>
      </tr>
       </thead>
       <tbody>
    {{ range . }}
      <tr>
        <td>{{ .Id }}</td>
        <td> {{ .Full_Name }} </td>
        <td>{{ .Address }} </td> 
        <td><a href="/show?id={{ .Id }}">View</a></td>
        <td><a href="/edit?id={{ .Id }}">Edit</a></td>
        <td><a href="/delete?id={{ .Id }}">Delete</a><td>
      </tr>
    {{ end }}
       </tbody>
    </table>
  {{ template "Footer" }}
{{ end }}

Create another template file in same folder for this i have created a template file named Header.tmpl

{{ define "Header" }}
<!DOCTYPE html>
<html lang="en-US">
    <head>
        <title>CRUD app using Golang </title>
        <meta charset="UTF-8" />
    </head>
    <body>
        <h1>Golang Mysql Curd Example</h1>   
{{ end }}

Again you have to create another template file in same folder for this i have created a template file named Footer.tmpl

{{ define "Footer" }}
    </body>
</html>
{{ end }}

Again you have to create another template file in same folder for this i have created a template file named Menu.tmpl

{{ define "Menu" }}
<a href="/">HOME</a> | 
<a href="/new">NEW</a>
{{ end }}

Again you have to create another template file in same folder for this i have created a template file named Show.tmpl

{{ define "Show" }}
  {{ template "Header" }}
    {{ template "Menu"  }}
    <h2> Register {{ .Id }} </h2>
      <p>Name: {{ .Full_Name }}</p>
      <p>City:  {{ .Address }}</p><br /> <a href="/edit?id={{ .Id }}">Edit</a></p>
  {{ template "Footer" }}
{{ end }}

Again you have to create another template file in same folder for this i have created a template file named New.tmpl

{{ define "New" }}
  {{ template "Header" }}
    {{ template "Menu" }} 
   <h2>New Name and Address</h2>  
    <form method="POST" action="insert">
      <label> Full Name </label><input type="text" name="fullname" /><br />
      <label> Address</label><input type="text" name="Address" /><br />
      <input type="submit" value="Submit" />
    </form>
  {{ template "Footer" }}
{{ end }}

At last create another template file for updating item for this we can create a file named Edit.tmpl

{{ define "Edit" }}
  {{ template "Header" }}
    {{ template "Menu" }} 
   <h2>Edit Name and City</h2>  
    <form method="POST" action="update">
      <input type="hidden" name="uid" value="{{ .Id }}" />
      <label> Full Name </label><input type="text" name="fullname" value="{{ .Full_Name }}"  /><br />
      <label> Address </label><input type="text" name="Address" value="{{ .Address }}"  /><br />
      <input type="submit" value="Submit" />
    </form><br />    
  {{ template "Footer" }}
{{ end }}

Congratulation! we have created our CRUD application using Golang and MySQL
Now you are good to go..

Run following command:

$ go run main.go

You can view it on following address

http://localhost:8080

Enjoy!!
Happy Coding !