如何以编程方式创建 localdb .mdf？

如何以编程方式创建 localdb .mdf？

可接受的解决方案excludeVisual Studio、ssms、aspnet_regsql。

一个简单的解决方案可能看起来像这样：

static void Main(string[] args)
{
    using (var con = new SqlConnection(@"Integrated Security=SSPI;Data Source=(LocalDb)\v11.0;AttachDbFilename=test.mdf"))
    {
        con.Open();
        using (var cmd = new SqlCommand("CREATE DATABASE test", con))
        {
            cmd.CommandType = CommandType.Text;
            cmd.ExecuteNonQuery();
        }
    }
}

但当然，这在 SqlConnection.Open 中失败并出现错误

尝试为文件 test.mdf 附加自动命名数据库失败。存在同名数据库，或无法打开指定文件，或位于 UNC 共享上。

如果指定的 .mdf 不存在，则无法连接到数据库。

那么...如何创建一个呢？

不得不从 Stackoverflow 和伟大的人那里拼凑出几个答案SQL Server 2012 Express LocalDB 入门 https://www.mssqltips.com/sqlservertip/2694/getting-started-with-sql-server-2012-express-localdb/文章来自@AaronBertrand

代码假设已安装 Dapper.NET：

PM> 安装包Dapper https://www.nuget.org/packages/Dapper

程序化创建：

var dbServerName = "SERVER_NAME";
var dbName = "DATABASE_NAME";

var infoResult = SqlLocalDbCommand($"info {dbServerName}");

var needsCreated = infoResult?.Trim().EndsWith($"\"{dbServerName}\" doesn't exist!");

if (needsCreated.GetValueOrDefault(false))
{
    var createResult = SqlLocalDbCommand($"create {dbServerName} -s");

    var success = createResult?.Trim().EndsWith($"\"{dbServerName}\" started.");

    if (false == success)
    {
        var msg = $"Failed to create database:{Environment.NewLine}{createResult}"
        throw new ApplicationException(msg);
    }

    var master = $@"Server=(localdb)\{dbServerName};Integrated Security=True;"
    using (var conn = new SqlConnection(master))
    {
        var result = conn.Execute($"CREATE DATABASE {dbName}");
    }

  var @new = $@"Server=(localdb)\{dbServerName};Integrated Security=True;Database={dbName}"
    using (var conn = new SqlConnection(@new))
    {
        //verify i can access my new database
        var tables = conn.Query($"SELECT * FROM {dbName}.INFORMATION_SCHEMA.Tables");
    }
}

Helper (谢谢T30 https://stackoverflow.com/a/29753402/37055):

/// <summary>
///     Executes a command against SqlLocalDB
/// </summary>
/// <remarks></remarks>
/// <param name="arguments">The arguments to pass to SqlLocalDB.exe</param>
/// <returns></returns>
/// <exception cref="System.ApplicationException">Error returned from process</exception>
private static string SqlLocalDbCommand(string arguments)
{
    var process = new Process
    {
        StartInfo =
        {
            FileName = "SqlLocalDB",
            Arguments = arguments,
            UseShellExecute = false,
            RedirectStandardOutput = true,
            RedirectStandardError = true
        }
    };

    process.Start();
    //* Read the output (or the error)
    var output = process.StandardOutput.ReadToEnd();
    Console.WriteLine(output);
    var err = process.StandardError.ReadToEnd();
    Console.WriteLine(err);
    process.WaitForExit();

    if (err.Exists()) throw new ApplicationException(err); //Is LocalDB installed?

    return output;
}

请注意，使用此解决方案，您将看不到 mdf 文件，我确信它们存在于某个用户文件夹中，但关键是您将通过连接字符串进行连接

(localdb)\SERVER_NAME;Integrated Security=True;Database=DATABASE_NAME