I mm running an SQL query to check if a table exists using the Gorm library for Golang. Below is my code.
package main
import (
"fmt"
"log"
"gorm.io/driver/postgres"
"gorm.io/gorm"
_ "github.com/lib/pq"
)
// App sets up and runs the app
type App struct {
DB *gorm.DB
}
`const tableCreationQuery = `SELECT count (*)
FROM information_schema.TABLES
WHERE (TABLE_SCHEMA = 'api_test') AND (TABLE_NAME = 'Users')`
func ensureTableExists() {
if err := a.DB.Exec(tableCreationQuery); err != nil {
log.Fatal(err)
}
}`
The expected response should be either 1
or 0
. I got this from another Stack Overflow answer. Instead I get this:
2020/09/03 00:27:18 &{0xc000148900 1 0xc000119ba0 0} exit status 1 FAIL go-auth 0.287s
My untrained mind says its a pointer but how do I reference the returned values to determine what was contained within?
If you want to check if your SQL statement was successfully executed in GORM you can use the following:
tx := DB.Exec(sqlStr, args...)
if tx.Error != nil {
return false
}
return true
However in your example are using a SELECT statement then you need to check the result, which will be better suited to use the DB.Raw() method like below
var exists bool
DB.Raw(sqlStr).Row().Scan(&exists)
return exists