C＃Sql命令帮助 [英] C# Sql command help

问题描述

我有一个sql UPDATE命令，我有一些麻烦。在我的数据库中，我有3个相似的（具有相同的规格）列，这些列包含一行数字，其中81个字符始终为81个字符长。我有一个正常的INSERT INTO命令，它可以正常工作。但是当我使用UPDATE命令更新这些时。我得到一个问题，在第一个数字后面放一个逗号：

示例（正常：987987987，有问题的代码：9,8798797）如何在没有逗号的情况下执行此操作？

以下是代码：

ki1 / 2/3是包含数字行的字符串。

I have a sql UPDATE command that i have some trouble with. In my database i have 3 similar(have the same specs) columns these columns contain a line of numbers which is 81 char always 81 char long. I have a normal INSERT INTO command which works fine. but when i use the UPDATE command to update these. I get a problem where after the first number it puts a comma:
Example(normal:987987987, with problematic code:9,8798797) how can i do it without the comma?
Here is the code:
ki1/2/3 are strings that contain the line of numbers.

OleDbConnection con1 = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=userstat.accdb;Persist Security Info=false;");
                con1.Open();
                OleDbCommand cmd1 = new OleDbCommand("UPDATE save SET mapfull="+ki1+",mapinitial="+ki2+",mapcurrent="+ki3+";", con1);
                cmd1.ExecuteNonQuery();
                con1.Close();

推荐答案

因为ki1 / ki2 / ki3是字符串，你 会有 引用它们。我假设你在insert语句中做了这件事而忘了这里。



但是：你不应该构建你的查询字符串无论如何，通过将值连接为文字。



相反，您应该使用SQL参数。请参阅我以前的一个答案，其中我写了一个示例性的良好实践数据库访问（那里的选择语句，但无关紧要）。我还解释了SQL参数的优点：



如何循环sql server表来创建datagridview - sql表字段匹配csv字段 [ ^ ]





编辑：代码格式有点混乱不幸的是，因为这个网站存在轻微的错误。代码中有一个< pre> -Tag，不属于那里，最后一行不再是代码块的一部分。

As ki1/ki2/ki3 are strings you would have to quote them. I assume you did that in your insert-statement and just forgot that here.

But: You shouldn't build your query-strings by concatenating the values as literals anyway.

Instead you should use SQL-Parameters. Please see one of my previous answers where I wrote an exemplary "good practice" database-access (a select-statement there but that doesn't matter). I also explain there the advantages of SQL-Parameters:

how to loop sql server table to create a datagridview - sql table field matches csv field[^]


The code-formatting is a bit messed up there, unfortunately, because of slight bugs with this website. There's a <pre>-Tag in the code that doesn't belong there and the last line isn't part of the code-block any more.

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