So we have a Person with a Name. A First and Last name.
Let's insert the Person with the First and Last name and query for the Person by Name.First again. How?
package main
import (
"fmt"
"log"
"github.com/jinzhu/gorm"
)
var (
pgHost string
pgUser string
pgDatabase string
pgPass string
)
type Person struct {
gorm.Model
Name *Name
NameID uint
}
type Name struct {
gorm.Model
PersonID uint
First string
Last string
}
func main() {
// let's assume they're set
db, e := gorm.Open("postgres", fmt.Sprintf("host=%s user=%s dbname=%s password=%s sslmode=disable", pgHost, pgUser, pgDatabase, pgPass))
if e != nil {
log.Fatal(e)
}
defer db.Close()
db.AutoMigrate(&Person{}, &Name{})
p := &Person{
Name: &Name{First: "First", Last: "Last"},
}
tx := db.Begin()
if c := tx.Create(p); c.Error != nil {
log.Fatal("tx.create", c.Error)
}
tx.Commit()
// let's find it
pq := &Person{Name: &Name{First: "First"}}
pr := new(Person)
if c := db.Where(pq).First(pr); c.Error != nil {
log.Fatal("db.Where", c.Error)
}
}
Error Message
converting Exec argument $1 type: unsupported type Name, a struct
Feel free to suggest alternatives, change structs, etc.
No, adding NameFirst and NameLast fields isn't acceptable. The 2 structs should remain intact.
Remove the pointer and it will work
Reference:
http://jinzhu.me/gorm/associations.html
Related
I'm trying to query from multiple databases. Each database is connected using the following function:
func connectDB(dbEnv str) *sql.DB{
// Loading environment variables from local.env file
err1 := godotenv.Load(dbEnv)
if err1 != nil {
log.Fatalf("Some error occured. Err: %s", err1)
}
dialect := os.Getenv("DIALECT")
host := os.Getenv("HOST")
dbPort := os.Getenv("DBPORT")
user := os.Getenv("USER")
dbName := os.Getenv("NAME")
password := os.Getenv("PASSWORD")
// Database connection string
dbURI := fmt.Sprintf("port=%s host=%s user=%s "+"password=%s dbname=%s sslmode=disable", dbPort, host, user, password, dbName)
// Create database object
db, err := sql.Open(dialect,dbURI)
if err != nil {
log.Fatal(err)
}
return db
}
type order struct{
OrderID string `json:"orderID"`
Name string `json:"name"`
}
type book struct{
OrderID string `json:"orderID"`
Name string `json:"name"`
}
func getOrders(db *sql.DB) []order {
var (
orderID string
name string
)
var allRows = []order{}
query := `
SELECT orderID, name
FROM orders.orders;
`
//Get rows using the query
rows, err := db.Query(query)
if err != nil { //Log if error
log.Fatal(err)
}
defer rows.Close()
// Add each row into the "allRows" slice
for rows.Next() {
err := rows.Scan(&orderID, &name, &date)
if err != nil {
log.Fatal(err)
}
//Create new order struct with the received data
row := order{
OrderID: orderID,
Name: name,
}
allRows = append(allRows, row)
}
//Log if error
err = rows.Err()
if err != nil {
log.Fatal(err)
}
return allRows
}
func getBooks(db *sql.DB) []book{
var (
bookID string
name string
)
var allRows = []book{}
query := `
SELECT bookID, name
FROM books.books;
`
//Get rows using the query
rows, err := db.Query(query)
if err != nil { //Log if error
log.Fatal(err)
}
defer rows.Close()
// Add each row into the "allRows" slice
for rows.Next() {
err := rows.Scan(&bookID, &name)
if err != nil {
log.Fatal(err)
}
//Create new book struct with the received data
row := book{
BookID: bookID,
Name: name,
}
allRows = append(allRows, row)
}
//Log if error
err = rows.Err()
if err != nil {
log.Fatal(err)
}
return allRows
}
func main() {
ordersDB:= connectDB("ordersDB.env")
booksDB:= connectDB("booksDB.env")
orders := getOrders(ordersDB)
books := getBooks(booksDB)
}
The issue is that when I use ordersDB first, the program only recognizes the table in ordersDB. And when I use booksDB first, the program only recognizes the table in booksDB.
When I try to query a table in booksDB after using ordersDB, it is giving me "relation "books.books" does not exist" error. When I try to query a table in ordersDB after using booksDB, it gives "relation "orders.orders" does not exist"
Is there a better way to connect to multiple databases?
You are using github.com/joho/godotenv to load the database configuration from the environment. Summarising (and cutting out a lot of detail) what you are doing is:
godotenv.Load("ordersDB.env")
host := os.Getenv("HOST")
// Connect to DB
godotenv.Load("booksDB.env")
host := os.Getenv("HOST")
// Connect to DB 2
However as stated in the docs "Existing envs take precedence of envs that are loaded later". This is also stated more clearly here "It's important to note that it WILL NOT OVERRIDE an env variable that already exists".
So your code will load in the first .env file, populate the environment variables, and connect to the database. You will then load the second .env file but, because the environmental variables are already set, they will not be changed and you will connect to the same database a second time.
As a work around you could use Overload. However it's probably better to reconsider your use of environmental variables (and perhaps use different variables for the second connection).
I want to insert to database from CSV file using gorm AutoMigrate and while inserting I want to avoid duplicate entry. How Can I achieve this? Please check the attached code.
type User struct {
gorm.Model
ID int64 `csv:"_" db:"id"`
FirstName string `csv:"First name" db:"first_name"`
LastName string `csv:"Last name" db:"last_name"`
Emails string `csv:"Emails" db:"emails"`
}
func main() {
file, err := os.Open(os.Args[1])
defer file.Close()
users := []User{}
err = gocsv.Unmarshal(file, &users)
db, err := gorm.Open(postgres.Open("host=xxx.xx.x.x user=database password=password dbname=database port=5432 sslmode=disable"))
err = db.AutoMigrate(&User{})
if err != nil {
panic(err)
}
result := db.Create(users)
if result.Error != nil {
panic(result.Error)
}
}
Example: Consider the below data
FIrst name
Last name
Emails
First
Name
first#example.com
Second
Name
second#example.com
Third
Name
Forth
Name
first#example.com
If we pass the above data, the first 3 rows should insert into the database i.e. we have to avoid duplicate email entries to the database. Thanks.
Note: If the email is empty then the row should be inserted into the database.
You have to sanitize "users" after err = gocsv.Unmarshal(file, &users)
Somethink like
func sanytize(arr []User) []User {
users := []User{}
mail := []string{}
for _, a := range arr {
if !contains(mail, a.Emails){
users = append(users, a)
}
mail = append(mail, a.Emails)
}
return users
}
func contains(arr []string, str string) bool {
for _, a := range arr {
if a == str {
return true
}
}
return false
}
....
err = gocsv.Unmarshal(file, &users)
users = sanytize(users)
I am trying to update a record in a postgres table with an array (slice) of values. The table has the following DDL:
CREATE TABLE slm_files (
id uuid DEFAULT gen_random_uuid() PRIMARY KEY,
filename character varying NOT NULL,
status character varying NOT NULL,
original_headers text[]
);
and the Go code I have is as follows:
package main
import (
"context"
"database/sql"
"encoding/json"
"fmt"
"os"
"strings"
"time"
"github.com/aws/aws-lambda-go/events"
"github.com/aws/aws-lambda-go/lambda"
"github.com/lib/pq"
)
type message struct {
ID string `json:"id"`
Filename string `json:"filename"`
Status string `json:"status"`
OriginalHeaders []string `json:"OriginalHeaders"`
}
func main() {
host := os.Getenv("PGhost")
port := 5432
user := os.Getenv("PGuser")
password := os.Getenv("PGpassword")
dbname := os.Getenv("PGdbname")
pgConString := fmt.Sprintf("port=%d host=%s user=%s "+
"password=%s dbname=%s sslmode=disable",
port, host, user, password, dbname)
msgBody := `update_headers___
{
"id": "76b67119-d8c1-4a20-b53e-49e4972e2f19",
"filename": "SLM1171_inputData_preNCOA-5babc88b-1d14-468d-bf6e-c3b36ce90d95.csv",
"status": "Submitted",
"OriginalHeaders": [
"city",
"state",
"zipcode",
"full_name",
"individual_id"
]
}`
fmt.Println("Processing file", msgBody)
queryMethod := strings.Split(msgBody, "___")[0]
fieldDict := strings.Split(msgBody, "___")[1]
db, err := sql.Open("postgres", pgConString)
if err != nil {
panic(err)
}
fmt.Println("Connected Successfully")
defer db.Close()
body := message{}
json.Unmarshal([]byte(fieldDict), &body)
fmt.Println(queryMethod)
fmt.Println(body)
var sqlStatement string
switch queryMethod {
case "update_ncoa":
sqlStatement = fmt.Sprintf(`UPDATE slm_files SET status = '%s', updated_at = '%s' where id = '%s';`,
body.Status,
body.UpdatedAt,
body.ID,
)
case "update_headers":
sqlStatement = fmt.Sprintf(`UPDATE slm_files SET original_headers = '%s', updated_at = '%s' where id = '%s';`,
pq.Array(body.OriginalHeaders),
body.UpdatedAt,
body.ID,
)
}
fmt.Println(sqlStatement)
_, err = db.Query(sqlStatement)
if err != nil {
fmt.Println("Failed to run query", err)
return
}
}
fmt.Println("Query executed!")
return
}
but I keep getting the error
pq: malformed array literal: "&[first_name last_name city state zipcode full_name individual_id]": Error
null
I have read a few things on the internet that lead me to using pq.Array() but that doesnt seem to work.
I have read about the difference in format between Go arrays and Postgres arrays, so I had hoped that letting the pq.Array function would sort it out but apparently not.
As Peter advised, there's a lot to fix up with that database handling. And it's definitely worth redoing those SQL statements to not use Sprintf to make the query.
But in terms of just getting something working with postgres arrays and the pq library, you need to use the Value() method of pq.Array to get the postgres format. Change your update statement for the headers to something like this:
arrayVal, _ := pq.Array(body.OriginalHeaders).Value()
sqlStatement = fmt.Sprintf(`UPDATE slm_files SET original_headers = '%s', updated_at = '%s' where id = '%s';`,
arrayVal,
body.UpdatedAt,
body.ID,
)
And it's worth checking the return from the Value() method to make sure there are no errors, I just ignored it for the sake of a simple example.
I'm trying to implement a MongoDB update for a Go struct. Stripped down to essentials, it looks something like this:
type MyStruct struct {
Id bson.ObjectId `bson:"_id"`
Fruit string `bson:"fruit"`
}
func TestUpdate(t *testing.T) {
obj1 := MyStruct{Id: bson.NewObjectId(),Fruit: "apple"}
var obj2 MyStruct
session, _ := mgo.Dial("whatever")
col := session.DB("test").C("collection")
col.Insert(&obj1)
obj1.Fruit = "cherry"
if err := col.Update(obj1.Id, bson.M{"$set": &obj1}); err != nil {
t.Errorf(err.Error())
}
if err := col.Find(bson.M{"Id": obj1.Id}).One(&obj2); err != nil {
t.Errorf(err.Error())
}
if obj1.Fruit != obj2.Fruit {
t.Errorf("Expected %s, got %s", obj1.Fruit, obj2.Fruit)
}
}
This generates the error message, indicating that the value wasn't updated. What am I missing?
I understand that just updating one field is possible, but given that this is in a data layer, above which the code doesn't have any knowledge of MongoDB, that would be challenging to implement in a general way. I.e. I really need to make any updates to the Go object, and then update the copy of the object in the backing store. I suppose that I could retrieve the object and do a "diff" manually, constructing a "$set" document, but that doesn't seem like adding a retrieval every time I do an update would be very efficient.
Edit: Trying a map with "_id" deleted
I've tried amending the code to the following:
package testmgo
import (
mgo "gopkg.in/mgo.v2"
"gopkg.in/mgo.v2/bson"
"github.com/fatih/structs"
"testing"
)
type MyStruct struct {
Id bson.ObjectId `bson:"_id"`
Fruit string `bson:"fruit"`
}
func TestUpdate(t *testing.T) {
obj1 := MyStruct{Id: bson.NewObjectId(),Fruit: "apple"}
var obj2 MyStruct
session, _ := mgo.Dial("localhost")
col := session.DB("test").C("collection")
col.Insert(&obj1)
obj1.Fruit = "cherry"
omap := structs.Map(&obj1)
delete(omap, "_id")
if err := col.UpdateId(obj1.Id, bson.M{"$set": bson.M(omap)}); err != nil {
t.Errorf(err.Error())
}
if err := col.Find(bson.M{"Id": obj1.Id}).One(&obj2); err != nil {
t.Errorf(err.Error())
}
if obj1.Fruit != obj2.Fruit {
t.Errorf("Expected %s, got %s", obj1.Fruit, obj2.Fruit)
}
}
and am still receiving the same results (Expected cherry, got apple). Note that the call to UpdateId() is not returning an error.
The problem was that I was using the wrong field as the key. I had mapped "Id" to "_id", but was then asking MongoDB to find a record using the Go attribute name rather than the name. This works correctly:
package testmgo
import (
mgo "gopkg.in/mgo.v2"
"gopkg.in/mgo.v2/bson"
"testing"
)
type MyStruct struct {
Id bson.ObjectId `bson:"_id"`
Fruit string `bson:"fruit"`
}
func TestUpdate(t *testing.T) {
obj1 := MyStruct{Id: bson.NewObjectId(), Fruit: "apple"}
var obj2 MyStruct
session, _ := mgo.Dial("localhost")
col := session.DB("test").C("collection")
col.Insert(&obj1)
obj1.Fruit = "cherry"
if err := col.UpdateId(obj1.Id, bson.M{"$set": &obj1}); err != nil {
t.Errorf(err.Error())
}
if err := col.Find(bson.M{"_id": obj1.Id}).One(&obj2); err != nil {
t.Errorf(err.Error())
}
if obj1.Fruit != obj2.Fruit {
t.Errorf("Expected %s, got %s", obj1.Fruit, obj2.Fruit)
}
}
I was wondering if there is any way to have a stuct field that doesn't get commited to mgo even if it isn't empty.
The only way I have found to do this is to make the field lowercase, which makes it a pain to access. Is there another way?
This is an example, and my goal here is to not commit the SSN into the database but still have it uppercase.
package main
import (
"fmt"
"crypto/sha1"
"encoding/base64"
"labix.org/v2/mgo"
)
type Person struct{
Name string
SSN string
HashedSSN string
}
func main() {
bob := Person{"Bob", "fake_ssn", ""}
hasher := sha1.New()
hasher.Write( []byte(bob.SSN))
sha := base64.URLEncoding.EncodeToString(hasher.Sum(nil))
bob.HashedSSN = sha
mgoSession, err := mgo.Dial("localhost:27017")
if err != nil {
fmt.Println("mongo_config#initMongoSessions : Could not dial to mgoSession", err)
} else {
mgoSession.DB("test").C("person").Insert(bob)
}
}
Thanks,
You can do that by using the field tag as follows:
type T struct {
Field string `bson:"-"`
}