Develop Reference

Passing DateTime.Now into Access database

I am facing a problem on passing the DateTime.Now into Access database:
oleDBCommand.CommandText =
"INSERT INTO tblData "([PIC], [Sampling Date]) "VALUES (#PIC, #SamplingDate)";
oleDBCommand.Parameters.Add(new OleDbParameter("#PIC", combobox1.Text));
oleDBCommand.Parameters.Add(new OleDbParameter("#SamplingDate", DateTime.Now));
I tried a lot of methods from the internet like using oleDBType.Date, DateTime.Now.ToString(), using AddWithValue..... And none of it is working.
Note 1: Database setting [Sampling Date] = Data Type: Date/Time (Format - Long Time), database was
Note 2: Below code was working but I prefer to using .parameters as it look much more organize and easy to manage.
oleDBCommand.CommandText =
"INSERT INTO tblData ([PIC], [Sampling Date]) " VALUES ('" + combobox1.Text + "', '" + DateTime.Now + "')";

You dont need to pass parameter when specifying current date.
Let the ms access sql query handle it, you need to replace #SamplingDate parameter to Date() for example
cmd.CommandText = "INSERT INTO tblData ([PIC], [Sampling Date]) VALUES (#PIC, Date())";
Here is the best explanation Insert today's date

I was struggling with this this week and the accepted answer really did not help me. I found that if I did the assignment of the date+time as an ODBC canonical string (yyyy-mm-dd hh:mi:ss), it worked just fine. So, my C# code looked something like:
InsertCommand.Parameters.Add("#" + column.ColumnName, OleDbType.DBTimeStamp).Value = DateTime.Now.ToString("u");
for the first row and then
InsertCommand.Parameters.Add("#" + column.ColumnName).Value = DateTime.Now.ToString("u")
for the rest.

Try This,
cmd.CommandText = "INSERT INTO tblData ([PIC], [Sampling Date]) VALUES (#PIC, #SamplingDate)";
cmd.Parameters.Add("#PIC",OleDbType.VarChar).Value = combobox1.Text;
cmd.Parameters.Add("#PIC", OleDbType.Date).Value = DateTime.Now;
c# ms-access

insert datetime value gives error "Incorrect syntax near 12"

DateTime myDateTime = Convert.ToDateTime(rd2[0].ToString())
values = myDateTime.ToString("yyyy-MM-dd HH:mm:ss") + " , " + rd2[1].ToString()+ " , " + rd2[2].ToString()+ " , " + rd2[3].ToString()+ " , " + rd2[4].ToString()+ " , " + rd2[5].ToString() ;
i am trying to insert date 2016-04-22 12:58:11 in sql server table of datatype datetime but it gives error "Incorrect syntax near 12"

The string you end up with is similar to this:
2016-04-22 00:00:00,2016-04-22 00:00:00,2016-04-22 00:00:00,2016-04-22 00:00:00
Inserting that into a SQL statement is invalid. You need to wrap each date in single quotes so that you have:
'2016-04-22 00:00:00','2016-04-22 00:00:00','2016-04-22 00:00:00','2016-04-22 00:00:00'
Either way this makes your life difficult and makes your code subject to sql injection and insecure. Consider using parameters like this.
string exampleSQL = "SELECT * from mydatetable where dateOne = #date1 and dateTwo = #date2";
SqlConnection connection = new SqlConnection(/* connection info */);
SqlCommand command = new SqlCommand(sql, connection);
command.Parameters.Add("#date1", SqlDbType.DateTime).Value = myDateTime;
command.Parameters.Add("#date2", SqlDbType.DateTime).Value = rd2[1];
This way you dont need to worry about formatting. The system automatically will replace the #date1 and #date2 with the values you specified and it will deal with adding the nescessary structure of the SQL without you having to worry about it.

I strongly suggest using "parametrizing your sql queries"...For example, you can check it out here:
http://www.dreamincode.net/forums/topic/268104-the-right-way-to-query-a-database-parameterizing-your-sql-queries/
Cheers!

C# query doesn't get executed

Currently I am trying to retrieve the contents of all the entries between a specific date in a MySQL database named 'orders'. To achieve this I use the following code:
query = "SELECT id, date, contactinfo, orderinfo, contents, print_location, order_id, file_size FROM orders where date between " + dateFrom + " and " + dateTill + " and print_location like 'antw'";
dateFrom and dateTill are both variables that contains timestamps.
Everything above works perfectly. The problem that I am facing right now is that I want to check on two print_locations instead of only one. As shown in the code above I only search on 'antw'. The code that I have right now to search on two print_locations is as follows:
query = "SELECT id, date, contactinfo, orderinfo, contents, print_location, order_id, file_size FROM orders where date between " + dateFrom + " and " + dateTill + " and print_location like 'antw' or print_location like 'helm'";
But somehow this doesn't work. I don't get an error the form just freezes and making it unaccessible.
This is probably a simple issue to resolve but I can't seem to solve it. The reason why I am only showing the value of the query variable and not the rest of my code is because everything has worked fine for weeks.

you forgot brackets and you should use parameters to avoid injection attack
string Command = "SELECT id, date, contactinfo, orderinfo, contents, print_location, order_id, file_size FROM orders where date between #dateFrom and #dateTill and (print_location like 'antw' or print_location like 'helm')";
using (MySqlConnection myConnection = new MySqlConnection(ConnectionString))
{
using (MySqlDataAdapter myDataAdapter = new MySqlDataAdapter(Command, myConnection))
{
myDataAdapter.SelectCommand.Parameters.Add(new MySqlParameter("#dateFrom", yourDateFrom));
myDataAdapter.SelectCommand.Parameters.Add(new MySqlParameter("#dateTill", yourdateTill));
DataTable dtResult = new DataTable();
myDataAdapter.Fill(dtResult);
}
}

Add brackets to your logic:
query = "SELECT id, date, contactinfo, orderinfo, contents, print_location, order_id, file_size FROM orders where date between " + dateFrom + " and " + dateTill + " and (print_location like 'antw' or print_location like 'helm')";
Be careful though... this smells like a potential case of SQL injection!

Never worked with MySQL, but maybe you're forgetting %% on your LIKE clauses. The way it is, it will work like =.
SELECT id, date, contactinfo, orderinfo, contents, print_location, order_id, file_size FROM orders where date between " + dateFrom + " and " + dateTill + " and (print_location like '%antw%' or print_location like '%helm%')

You need parentheses on your second set "OR" of conditions:
query = "SELECT id, date, contactinfo, orderinfo, contents, print_location, order_id, file_size FROM orders where date between " + dateFrom + " and " + dateTill + " and (print_location like 'antw' or print_location like 'helm')";
Otherwise, your statement reads like this:
Get me all this stuff, where date between this date and this date, and print_location like 'antw'...
Or get me all this stuff where print_location like 'helm'.
Since you're using a like, it's probably just freezing while executing your query. It would eventually finish, and you'd have way more results than you were expecting.
Also, because of injection concerns, and data modeling, you should really use a data access object model (DAO). I suggest researching it!

Converting a string into the Date datatype and inserting into the database

I have a rent_date and return_date column in rental table and the data-type is Date. I have created two different strings for them. rentDate is the current date and returnDate is the output of adding the days that the product is rented for, from the current date. I tried to convert the strings using to_date but its showing errors. I have tried it with the data-type varchar2(30). Worked fine. But had to modify to Date because I want a late return date too. Can anyone tell me what is wrong with this query?
DateTime dt = System.DateTime.Now;
string rentDate = dt.ToString();
// this is added to the current date of the user input and showed in the form
string returnDate = label66.Text;
string Query = "Insert into rental ( pr_ID, cid, rent_date, Return_date, status, receipt_no) values ( '" + comboBox5.Text + "' , '" + comboBox4.Text + "', (to_date('" + rentDate + "','dd/mm/yyyy')), (to_date('" + returnDate + "','dd/mm/yyyy')), '" + Status + "', '" + txt_recpt.Text + "') ";

What error are you getting?
I agree with the "Soner" that they should not be text values. However, based on your existing code, you may be getting a format error.
What format is the string value of "rentDate" and "returnDate" in? It needs to be the same as what you've specified in the INSERT query, which is "dd/mm/yyyy". If it's not, an error will be thrown.
The second parameter of the TO_DATE function is the format of the input variable.
Unless you're getting a different error?

Compare date from database using parameters

string queryString = "SELECT SUM(skupaj_kalorij)as Skupaj_Kalorij "
+ "FROM (obroki_save LEFT JOIN users ON obroki_save.ID_uporabnika=users.ID)"
+ "WHERE (users.ID= " + a.ToString() + ") AND (obroki_save.datum= #datum)";
using (OleDbCommand cmd = new OleDbCommand(queryString,database))
{
DateTime datum = DateTime.Today;
cmd.Parameters.AddWithValue("#datum", datum);
}
loadDataGrid2(queryString);
I tried now with parameters. But i don't really know how to do it correctly. I tried like this, but the parameter datum doesn't get any value(according to c#).

please try this :
database = new OleDbConnection(connectionString);
database.Open();
date = DateTime.Now.ToShortDateString();
string queryString = "SELECT SUM(skupaj_kalorij)as Skupaj_Kalorij "
+ "FROM (obroki_save LEFT JOIN users ON obroki_save.ID_uporabnika=users.ID)"
+ "WHERE users.ID= " + a.ToString()+" AND obroki_save.datum= '" +DateTime.Today.ToShortDateString() + "'";
loadDataGrid2(queryString);
when you use with Date, you must write like this
select * from table where date = '#date'
not like
select * from table where date = #date

While it's usually useful to post the error, I'd hazard a guess and say that you're getting a conversion error with your date.
You should really look at parameterising your queries...
You should read this: http://www.aspnet101.com/2007/03/parameterized-queries-in-asp-net/
And if you can't be bothered reading that, then try changing your 'a' variable to '1; DROP TABLE obroki; --' (but only after you back up your database).

Perhaps you need to write your SQL string in the SQL dialect of the database you're using. In Jet/ACE SQL (what's used by Access), the delimiter for date values is #, so you'd need this:
obroki_save.datum= #" +DateTime.Today.ToShortDateString() + "#"
Of course, some data interface libraries translate these things for you, so that may not be the problem here.