Correct DateTime format in SQL Server CE?

问题

I have a C# DateTime class and wanted to know how I need to format it in a SQL Server CE query to insert it into the database, I was hoping to have both the date and time inserted in. Currently when I try variations thereof I get invalid format exceptions.

Current format I'm using is: dd/MM/yyyy, was hoping to do something like dd/MM/yyyy hh:mm:ss.

The way I'm trying to do the insert is like so:

 ( ( DateTime )_Value ).ToString( "dd/MM/yyyy hh:mm:ss" )

Obviously hh:mm:ss isn't working, if that isn't there dd/MM/yyyy executes successfully in the query.

I've tried a few formats including what I've found on google but none have worked so far...

回答1:

If you're worried about getting the format right at all, something has already gone seriously wrong. There are two things you need to do to correctly work with datetime values in any database, not just sqlce:

Make sure you're using a datetime type for the column (not a text type like varchar)
Make sure you're using a datetime parameters in a parameterized query, and not string concatenation.

If you do that, there is no formatting involved on your part. At all. Example:

 void SetDate(int recordID, DateTime timeStamp)
 {
    string SQL = "UPDATE [sometable] SET someDateTimeColumn= @NewTime WHERE ID= @ID";

    using (var cn = new SqlCeConnection("connection string here"))
    using (var cmd = new SqlCeCommand(SQL, cn))
    {
        cmd.Parameters.Add("@NewTime", SqlDbType.DateTime).Value = timeStamp;
        cmd.Parameters.Add("@ID", SqlDbType.Integer).Value = recordID;

        cn.Open();
        cmd.ExecuteNonQuery();
    }
}

Never ever ever ever EVER use string manipulation to substitute values into sql queries. It's a huge no-no.

回答2:

Try the following format:

DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss")

回答3:

Man, you do not need to convert string to DateTime.

Use a instance of a new DateTime and pass the date as parameter. Like this:

using (var ctx = new DBPreparoEntities())
            {
                var _client = from p in ctx.Client
                                 select new Client
                                 {
                                     data = new DateTime(2016,08,17),
                                     dateconf = null,
                                     scod_cli = p.Rua,
                                     valorini = 7214.62m,
                                 };
                return client.ToList();
            }

don't use:

... data = DateTime.Parse("2016/12/10") // or other type convertions.

回答4:

sorry this is in vb.net, but this is a method i use to convert from a CE date/time format:

    Public Shared Function ConvertSqlDateTimeFormat(ByVal s As String) As String
    Dim theDate As New Text.StringBuilder
    Dim sTemp As String = ""
    Dim iIndex As Integer

    If s.Length > 8 Then
        'first we do the time
        iIndex = s.IndexOf(" ", System.StringComparison.OrdinalIgnoreCase)
        If iIndex > 0 Then
            sTemp = s.Substring(iIndex).Trim
            iIndex = sTemp.IndexOf(".", System.StringComparison.OrdinalIgnoreCase)
            If iIndex > 0 Then
                sTemp = sTemp.Substring(0, iIndex)
            End If
        End If

        'next the date
        theDate.Append(s.Substring(4, 2))
        theDate.Append("/")
        theDate.Append(s.Substring(6, 2))
        theDate.Append("/")
        theDate.Append(s.Substring(0, 4))
        theDate.Append(" ")
        theDate.Append(sTemp)
    End If
    Return theDate.ToString
End Function

来源：https://stackoverflow.com/questions/12031551/correct-datetime-format-in-sql-server-ce

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sql

datetime

sql-server-ce