In this tutorial, we are going to see an example program to learn how to do database CRUD operations using Golang and MySQL. CRUD is an acronym for Create, Read, Update, and Delete. CRUD operations are basic data manipulation for database.
In this example, we are going to create an interface as database front end to handle these operations. We have Employee table containing Employee information like id, name and city. With this table, we have to perform CRUD using MySQL.
Step 1: Prepare and Import MySQL driver into your project
Using Git Bash first install driver for Go's MySQL database package. Run below command and install MySQL driver's
go get -u github.com/go-sql-driver/mysql
Now create Goblog Database
1. Open PHPMyAdmin/SQLyog or what ever MySQL database management tool that you are using.
2. Create a new database "goblog"
Step 2: Creating the Employee Table
Execute the following SQL query to create a table named Employee inside your MySQL database. We will use this table for all of our future operations.
DROP TABLE IF EXISTS `employee`; CREATE TABLE `employee` ( `id` int(6) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(30) NOT NULL, `city` varchar(30) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1;
Step 3: Creating Struct, Handler and Handler Function
Let's create a file named main.go
and put the following code inside it.
We usually import database/sql and use sql to execute database queries on the database.
Function dbConn
opens connection with MySQL driver.
We will create Employee
struct that has following properties: Id, Name and City.
package main import ( "database/sql" "log" "net/http" "text/template" _ "github.com/go-sql-driver/mysql" ) type Employee struct { Id int Name string City 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 := Employee{} res := []Employee{} for selDB.Next() { var id int var name, city string err = selDB.Scan(&id, &name, &city) if err != nil { panic(err.Error()) } emp.Id = id emp.Name = name emp.City = city 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 Employee WHERE id=?", nId) if err != nil { panic(err.Error()) } emp := Employee{} for selDB.Next() { var id int var name, city string err = selDB.Scan(&id, &name, &city) if err != nil { panic(err.Error()) } emp.Id = id emp.Name = name emp.City = city } 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 Employee WHERE id=?", nId) if err != nil { panic(err.Error()) } emp := Employee{} for selDB.Next() { var id int var name, city string err = selDB.Scan(&id, &name, &city) if err != nil { panic(err.Error()) } emp.Id = id emp.Name = name emp.City = city } tmpl.ExecuteTemplate(w, "Edit", emp) defer db.Close() } func Insert(w http.ResponseWriter, r *http.Request) { db := dbConn() if r.Method == "POST" { name := r.FormValue("name") city := r.FormValue("city") insForm, err := db.Prepare("INSERT INTO Employee(name, city) VALUES(?,?)") if err != nil { panic(err.Error()) } insForm.Exec(name, city) log.Println("INSERT: Name: " + name + " | City: " + city) } defer db.Close() http.Redirect(w, r, "/", 301) } func Update(w http.ResponseWriter, r *http.Request) { db := dbConn() if r.Method == "POST" { name := r.FormValue("name") city := r.FormValue("city") id := r.FormValue("uid") insForm, err := db.Prepare("UPDATE Employee SET name=?, city=? WHERE id=?") if err != nil { panic(err.Error()) } insForm.Exec(name, city, id) log.Println("UPDATE: Name: " + name + " | City: " + city) } 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 Employee 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: Creating Template files
Now it's time to build the Template files of our CRUD application. Create form
folder at same location where we have created main.go
.
a)Let's create a file named Index.tmpl
inside the form
folder and put the following code inside it.
{{ define "Index" }} {{ template "Header" }} {{ template "Menu" }} <h2> Registered </h2> <table border="1"> <thead> <tr> <td>ID</td> <td>Name</td> <td>City</td> <td>View</td> <td>Edit</td> <td>Delete</td> </tr> </thead> <tbody> {{ range . }} <tr> <td>{{ .Id }}</td> <td> {{ .Name }} </td> <td>{{ .City }} </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 }}
b)Now create another file named Header.tmpl
inside the same form
folder and put the following code inside it.
{{ define "Header" }} <!DOCTYPE html> <html lang="en-US"> <head> <title>Golang Mysql Curd Example</title> <meta charset="UTF-8" /> </head> <body> <h1>Golang Mysql Curd Example</h1> {{ end }}
c)Now create another file named Footer.tmpl
inside the same form
folder and put the following code inside it.
{{ define "Footer" }} </body> </html> {{ end }}
d)Now create another file named Menu.tmpl
inside the same form
folder and put the following code inside it.
{{ define "Menu" }} <a href="/">HOME</a> | <a href="/new">NEW</a> {{ end }}
e)Next, we have to create Show.tmpl
file for item details page, so again create this file in form
folder.
{{ define "Show" }} {{ template "Header" }} {{ template "Menu" }} <h2> Register {{ .Id }} </h2> <p>Name: {{ .Name }}</p> <p>City: {{ .City }}</p><br /> <a href="/edit?id={{ .Id }}">Edit</a></p> {{ template "Footer" }} {{ end }}
f)Now we create new blade file for create new item, it's call New.tmpl
file inside form
.
{{ define "New" }} {{ template "Header" }} {{ template "Menu" }} <h2>New Name and City</h2> <form method="POST" action="insert"> <label> Name </label><input type="text" name="name" /><br /> <label> City </label><input type="text" name="city" /><br /> <input type="submit" value="Save user" /> </form> {{ template "Footer" }} {{ end }}
g)At last, we need to create Edit.tmpl
file for update item, so again create this file in form
folder.
{{ 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> Name </label><input type="text" name="name" value="{{ .Name }}" /><br /> <label> City </label><input type="text" name="city" value="{{ .City }}" /><br /> <input type="submit" value="Save user" /> </form><br /> {{ template "Footer" }} {{ end }}
After a long journey finally we've created all files of our CRUD application with Golang and MySQL.
Run the following command
go run main.go
Load the following URL
http://localhost:8080/
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