根据 web.config 检查 sqlce 数据库是否存在

发布于 2024-10-17 08:38:48 字数 1005 浏览 2 评论 0原文

请参阅问题如何检查数据库是否存在？我试图根据 web.config 连接字符串检测数据库是否存在，但运气不好。

我使用上面的最后一个答案作为我的试验。

试验一： web.config 中的连接字符串

    <add name="sqlCEConnString" connectionString="Data Source=|DataDirectory|db.sdf;Initial Catalog=master" providerName="System.Data.SqlServerCE.4.0"/>

我收到错误：不支持关键字：'初始目录'。

试验 2：没有关键字

字符串 conString = ConfigurationManager.ConnectionStrings["sqlCEConnString "].ConnectionString;

    using(SqlCeConnection cnn = new SqlCeConnection(conString))
    { 
        cnn.Open();
        using (SqlCeCommand com = new SqlCeCommand("select count(*) from sys.databases where name = 'db.sdf'" , cnn))
        {
            int j=com.ExecuteNonQuery();
            Response.Write("Result:" + j);
        }
    }

这次我得到了以下错误： 指定的表不存在。 [@@sys.databases]

我做错了什么？

原文

Refer to the question How to check for the existence of a DB? I was trying to detect the existence of a DB as per in web.config connection string, but out of luck.

I was using the last answer of the above as my trial.

Trial 1:
connection string in the web.config

    <add name="sqlCEConnString" connectionString="Data Source=|DataDirectory|db.sdf;Initial Catalog=master" providerName="System.Data.SqlServerCE.4.0"/>

I got the error: Keyword not supported: 'initial catalog'.

Trial 2: without the keyword

string conString = ConfigurationManager.ConnectionStrings["sqlCEConnString"].ConnectionString;

    using(SqlCeConnection cnn = new SqlCeConnection(conString))
    { 
        cnn.Open();
        using (SqlCeCommand com = new SqlCeCommand("select count(*) from sys.databases where name = 'db.sdf'" , cnn))
        {
            int j=com.ExecuteNonQuery();
            Response.Write("Result:" + j);
        }
    }

This time I got the following error:
The specified table does not exist. [ @@sys.databases ]

What I am doing wrong?

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少女的英雄梦 2024-10-24 08:38:48

最后我找到了根据连接字符串检测数据库是否存在的方法。在“SqlCeEngine”类下有一个名为“Verify”的方法，可以通过该方法进行检测。

        string conString = ConfigurationManager.ConnectionStrings["sqlCEConnectionString"].ConnectionString;
    using (SqlCeEngine objCeEngine = new SqlCeEngine(conString))
    {
        if (!objCeEngine.Verify())
        {
            objCeEngine.CreateDatabase();
        }
    }

Finally I found the way to detect whether the DB exists as per connection string. Under the "SqlCeEngine" class there is a method named "Verify" by which it is possible to detect.

        string conString = ConfigurationManager.ConnectionStrings["sqlCEConnectionString"].ConnectionString;
    using (SqlCeEngine objCeEngine = new SqlCeEngine(conString))
    {
        if (!objCeEngine.Verify())
        {
            objCeEngine.CreateDatabase();
        }
    }

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