使用C#在MySQL中更新语句 [英] Update statement in MySQL using C#

问题描述

我一直在为自己的工作场所建立一个小型库存系统，偶然发现了一个我似乎无法修复的错误

I've been building a small inventory system for my workplace and have stumbled on an error that I cannot seem to fix

 private void Update(string num,string name, string quant, string location, string category, string numquery)
    {
       // "UPDATE Inventory SET Inventorynumber='"+ num +"',Inventory_Name='"+name+"', Quantity ='"+ quant+"',Location ='"+ location+"' Category ='"+ category+"' WHERE Inventorynumber ='"+ numquery +"';";
        string query = "UPDATE Inventory SET Inventorynumber='" + Convert.ToInt16(num) + "',Inventory_Name='" + name + "', Quantity ='" + quant + "',Location ='" + location + "' Category ='" + category + "' WHERE Inventorynumber ='" + Convert.ToInt16(numquery) + "'";
        if (this.OpenConnection() == true)
        {
            MySqlCommand cmd = new MySqlCommand();
            cmd.CommandText = query;
            cmd.Connection = serverconnection;
            cmd.ExecuteNonQuery();
            this.CloseConnection();
            Bind();
        }
    }

我不知道在这里要更改什么. 任何帮助将不胜感激.

I have no idea what to change here. Any help would be appreciated.

推荐答案

问题:您在查询中的location参数后缺少comma.
解决方案:您需要使用comma分隔parameters.

Problem: You are missing the comma after location parameter in your query.
Solution: You need to separate the parameters using a comma.

建议::使用parameterized queries避免SQL Injection Attacks.

尝试一下:

private void Update(string num,string name, string quant, string location, string category, string numquery)
    {
       // "UPDATE Inventory SET Inventorynumber='"+ num +"',Inventory_Name='"+name+"', Quantity ='"+ quant+"',Location ='"+ location+"' Category ='"+ category+"' WHERE Inventorynumber ='"+ numquery +"';";
        string query = "UPDATE Inventory SET Inventorynumber=@Inventorynumber,Inventory_Name=@Inventory_Name, Quantity =@Quantity ,Location =@Location,Category =@Category WHERE Inventorynumber =@Inventorynumber";
        if (this.OpenConnection() == true)
        {
            MySqlCommand cmd = new MySqlCommand();
            cmd.CommandText = query;
            cmd.Parameters.AddWithValue("@Inventorynumber",Convert.ToInt16(num));
            cmd.Parameters.AddWithValue("@Inventory_Name",name);
            cmd.Parameters.AddWithValue("@Quantity",quant);
            cmd.Parameters.AddWithValue("@Location",location);
            cmd.Parameters.AddWithValue("@Category",category);
            cmd.Parameters.AddWithValue("@Inventorynumber",Convert.ToInt16(numquery));
            cmd.Connection = serverconnection;
            cmd.ExecuteNonQuery();
            this.CloseConnection();
            Bind();
        }
    }

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