如何打印数据集的单个值

发布于 2024-09-16 04:57:14 字数 298 浏览 3 评论 0原文

conn = new SqlConnection(@"Data Source=ASHISH-PC\SQLEXPRESS; initial catalog=bank; integrated security=true");
ada = new SqlDataAdapter("select total_amount from debit_account where account_no=12", conn);
ds = new DataSet();

ada.Fill(ds);

现在，我想打印数据集的值......如何？请帮我。

原文

conn = new SqlConnection(@"Data Source=ASHISH-PC\SQLEXPRESS; initial catalog=bank; integrated security=true");
ada = new SqlDataAdapter("select total_amount from debit_account where account_no=12", conn);
ds = new DataSet();

ada.Fill(ds);

Now, I want to print value of the dataset... how? Please help me.

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谜兔 2024-09-23 04:57:14

我建议这里最好的选择实际上不是 SqlDataAdapter 和 DataSet，而是 SqlCommand。试试这个：

using(SqlConnection conn = new SqlConnection(@"Data Source=ASHISH-PC\SQLEXPRESS; initial catalog=bank; integrated security=true"))
{
    conn.Open()
    using (SqlCommand command  = new SqlCommand("select total_amount from debit_account where account_no=12", conn)
    {
        var result = command.ExecuteScalar();
        Console.WriteLine("The total_amount for the account is {0}", result);
    }
}

ExecuteScalar() SqlCommand 上的 方法返回查询返回的第一行第一列中的值，这在这种情况下是理想的。

如果您绝对必须使用数据集，那么您需要执行以下操作：

using(SqlConnection conn = new SqlConnection(@"Data Source=ASHISH-PC\SQLEXPRESS; initial catalog=bank; integrated security=true"))
{
    conn.Open()
    using (SqlDataAdapter adapter = new SqlDataAdapter("select total_amount from debit_account where account_no=12", conn)
    {
        var ds = new DataSet();
        adapter.Fill(ds);
        Console.WriteLine("The total_amount for the account is {0}", ds.Tables[0].Rows[0][0]); // Get the value from the first column of the first row of the first table
    }
}

注意： 我已将这两个示例包装在 C# using 语句，这确保您的所有数据库资源都已清理，因此您不会遇到任何泄漏非托管资源的问题。这并不是特别困难或复杂，所以非常值得做

I'd suggest that the best option here isn't actually a SqlDataAdapter and DataSet, but rather a SqlCommand. Try this:

using(SqlConnection conn = new SqlConnection(@"Data Source=ASHISH-PC\SQLEXPRESS; initial catalog=bank; integrated security=true"))
{
    conn.Open()
    using (SqlCommand command  = new SqlCommand("select total_amount from debit_account where account_no=12", conn)
    {
        var result = command.ExecuteScalar();
        Console.WriteLine("The total_amount for the account is {0}", result);
    }
}

The ExecuteScalar() method on SqlCommand returns the value in the first column of the first row that your query returns, which is ideal in this situation.

If you absolutely have to use a dataset then you'd want to do the following:

using(SqlConnection conn = new SqlConnection(@"Data Source=ASHISH-PC\SQLEXPRESS; initial catalog=bank; integrated security=true"))
{
    conn.Open()
    using (SqlDataAdapter adapter = new SqlDataAdapter("select total_amount from debit_account where account_no=12", conn)
    {
        var ds = new DataSet();
        adapter.Fill(ds);
        Console.WriteLine("The total_amount for the account is {0}", ds.Tables[0].Rows[0][0]); // Get the value from the first column of the first row of the first table
    }
}

Note: I've wrapped both examples in the C# using statement, this ensures that all your database resources are cleaned up so you don't have any problems with with leaking unmanaged resources. It's not particularly difficult or complicated so is well worth doing

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