如何使用Golang SDK查询RDS的任何表格 [英] How to query any table of RDS using Golang SDK

问题描述

我正在编写一个AWS Lambda，以使用Golang SDK从RDS(SQL Server)查询10个不同的表.到目前为止，我了解到的是我们必须为该表创建一个类似的结构以对其进行查询.但是，由于我要查询10个表，所以我不想为每个表创建结构，即使表架构有一天可能会更改.

I am writing an AWS lambda to query 10 different tables from RDS(SQL Server) using Golang SDK. What I have learned so far is we have to create a similar struct for the table to query it. But as I want to query 10 tables, So I don't want to create the struct for every table, even the table schema may get changed someday.

最近，我想为每个表创建一个CSV文件作为包含查询数据的备份，并将其上传到S3.那么是否可以将CSV文件直接导入到lambda中，以便我可以直接将其上传到S3? 您可以在下面看到我当前的代码

Lately, I want to create a CSV file per table as the backup with the queried data and upload it to S3. So is it possible to directly import the CSV file into a lambda, so that I can directly upload it to S3? You can see my current code below

func executeQuery(dbconnection *sql.DB) {

    println("\n\n----------Executing Query ----------")
    query := "select TOP 5 City,State,Country from IMBookingApp.dbo.Address"

    rows, err := dbconnection.Query(query)
    if err != nil {
        fmt.Println("Error:")
        log.Fatal(err)
    }

    println("rows", rows)

    defer rows.Close()
    count := 0
    for rows.Next() {
        var City, State, Country string

        rows.Columns

        err := rows.Scan(&City, &State, &Country)

        if err != nil {
            fmt.Println("Error reading rows: " + err.Error())
        }

        fmt.Printf("City: %s, State: %s, Country: %s\n", City, State, Country)
        count++
    }
}

此代码仅适用于Address表，不适用于其他表

This code can only work for the Address table, and not for other tables

我也尝试过GORM

package main

import (
    "fmt"
    "github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/mssql"
)

type Currency struct {
    CurrencyId  int    `gorm:"column:CurrencyId;"`
    Code        string `gorm:"column:Code;"`
    Description string `gorm:"column:Description;"`
}

func main() {
    db, err := gorm.Open("mssql", "sqlserver://***")
    db.SingularTable(true)

    gorm.DefaultTableNameHandler = func(dbVeiculosGorm *gorm.DB, defaultTableName string) string {
        return "IMBookingApp.dbo.Currency"
    }

    fmt.Println("HasTable-Currency:", db.HasTable("ClientUser"))
    var currency Currency
    db.Debug().Find(&currency)

    fmt.Println("Currency:", currency)
    fmt.Println("Error", err)

    defer db.Close()

}

使用这两种方法，我找不到使通用代码适用于多个表的任何方法.如果有人可以给我一些建议或您可以指向一些资源，我将不胜感激.

With both the approaches I couldn't find any way to make the code generic for multiple tables. I would appreciate it if anyone can give me some suggestions or if you can point to some resources.

推荐答案

下面的代码对我有用-

conn, _ := getConnection()   // Get database connection

rows, err := conn.Query(query)
if err != nil {
    fmt.Println("Error:")
    log.Fatal(err)
}

defer rows.Close()

columns, err := rows.Columns()

if err != nil {
    panic(err)
}

for rows.Next() {
    receiver := make([]string, len(columns))

    is := make([]interface{}, len(receiver))
    for i := range is {
        is[i] = &receiver[i]

        // each is[i] will be of type interface{} - compatible with Scan()
        // using the underlying concrete `*string` values from `receiver`
    }

    err := rows.Scan(is...)

    if err != nil {
        fmt.Println("Error reading rows: " + err.Error())
    }
    fmt.Println("receiver", receiver)

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