How to separate time from datetimepicker vb.net - mysql

I have one datetimepicker which custom format MM/dd/yyyy h:mm tt
I have database and has a column "Date_Time" the value of the DateTimePicker is saved to the column Date_Time formatted like this MM/dd/yyyy h:mm tt
now i want to get the Time only not the entire value of datetimepicker just the hh:mm tt from the column Date_Time
SORRY FOR MY GRAMMAR

How about DateTime.TimeOfDay?
It returns the time that has elapsed since midnight (which is what h:mm tt stands for in your code).
Dim Time As TimeSpan = DateTimePicker1.Value.TimeOfDay 'Would return for example 3:14 PM

The answer above is right.
If you need to get time string, you can use also another way, which includes a formating:
Dim myTimeString = DateTimePicker1.value.ToString("hh:mm")
You can do that for any part of the DateTime value.

You are heading for a new problem. If you zero out the Date portion and store the result to a DateTime column, you will end up storing something like: 0001-01-01 16:43:12. A column defined as DateTime will always have a Date, as will a DateTime variable.
The first problem may be getting MySQL to accept a non-Date in a DateTime column. Using a column defined as DateTime(3), mine throws a generic fatal error exception trying to store just a TimeSpan to it:
cmd.Parameters.Add("#p3", MySqlDbType.DateTime).Value = DateTime.Now.TimeOfDay
cmd.ExecuteNonQuery()
If MySqlDbType.Time is used as the type, I get an exception that the time is an invalid value for the column...and it is.
If you manage to store it somehow, the next problem will be when/if you want to put that value back in a DateTimePicker: the minimum date you can enter is 1/1/1753 (first full year of the current calendar). So your DateTime var with the Date zeroed out wont work. You'll first have to restore the date portion, but the Date, Year etc are all readonly.
Solution 1
Define the column as Time(0) which will store hours, minutes and seconds. Use the value in the parens to specify fractional seconds, for instance Time(3) will also store milliseconds. When you read the data, store it to a TimeSpan.
Then in your UI use a different control, otherwise you have the same problem - adding some Date data to it to make it usable in a DateTimePicker
Solution 2
Use a DateTimePicker and a DateTime column, but just ignore the Date portion in your code. This will allow you to use what is in the Database as is with the control.
You can get the time selected with DateTime.TimeOfDay but storing and reusing it may be problematic.

Related

How to use Time Data type only in Rails?

I use time as datatype in my rails migration but when I am retrieving it in model
it includes date. I wanted to be able to compute time difference without date.
Any way I can do to make my model return time only ?
I wanted this 03:15:00 not this 2000-01-01 05:54:42
If you want to convert a Datetime object into a Time object, you can use Time.parse.
date_and_time = Time.now # 2000-01-01 05:54:42
time_only = Time.parse(date_and_time) # 05:54:42
If you use the time data type for a column in your database migration you should be fine. Rails fills the missing fields (in this case year, month, day) with default values since the data type requires them. Since all responses get these default values you should be able to calculate time differences without date since all values have the same default value. If you want to get the time as string back in the format you want you can use #strftime method.
Eg:
time.strftime('%H:%M:%S')

How to check if a string contains a date?

I'm trying to iterate on a DataSet, this contain a results of query such as SELECT * FROM tb 1, now the first three field contains a date, the format saved in the database table is this:
yyyy-MM-dd HH:mm:ss
but the code return this:
yyyy/MM/dd HH:mm:ss
in particular this:
For z = 1 To ds.Tables(0).Columns.Count - 1
Console.WriteLine(ds.Tables(0).Rows(x)(z).ToString())
Next
So I need to recognize if the current string have this format: yyyy/MM/dd HH:mm:ss and parse it into: yyyy-MM-dd HH:mm:ss I tough to a regex pattern for recognize it, but I'm not an expert of regex. Anyway, if there is another solution I'll glad to see. Note that only the first three value and the last one of the table is date, the other values aren't date but contain integer or other string value.
Dates do not have a format. From MSDN:
Represents an instant in time, typically expressed as a date and time of day.
...
Time values are measured in 100-nanosecond units called ticks, and a particular date is the number of ticks since 12:00 midnight, January 1, 0001 A.D. (C.E.) in the GregorianCalendar calendar...For example, a ticks value of 31241376000000000L represents the date, Friday, January 01, 0100 12:00:00 midnight.
So, a DateTime is just a Big Number. Representing them as "dd/MM/yyyy" is part of the magic of the DateTime type. Part of the issue is this:
Console.WriteLine(ds.Tables(0).Rows(x)(z).ToString())
Row items are Object. It wont act like a DateTime type unless/until you get it into a DateTime variable. That print as a DateTime simple because the DataTable knows the underlying type; but it will use the default format for your Culture. This makes it look like dates have a built in format (or even that the "format changed" if you tried to set it to something), but you are a human and 635882810022222112L would not make sense to most of us.
To change the output style, you first need to get it into a DateTime variable. Apparently, a preliminary step is to determine if an arbitrary column is a Date. Rather than testing the "format" of the output, test the underlying data type. This does assume a proper DateTime column in the DataTable:
If ds.Tables(0).Columns(n).DataType = GetType(DateTime) Then
'...
End If
' Or:
If ds.Tables(0).Rows(x)(z).GetType Is GetType(DateTime) Then
'...
End If
Then to change the display, first get it into a DateTime variable:
Dim dt As DateTime
If ds.Tables(0).Rows(x)(z).GetType Is GetType(DateTime) Then
dt = Convert.ToDateTime(ds.Tables(0).Rows(x)(z))
' cant change "format" but you can change how it displays:
Console.WriteLine(dt.ToLongDateString)
Console.WriteLine(dt.ToString("yyyy-MM-dd HH:mm tt"))
Console.WriteLine(dt.ToString("dd MMM, yyyy"))
End If
An easier way to get and convert to DateTime is to use the Field(Of T) extension:
Dim dt = ds.Tables(0).Rows(x).Field(Of DateTime)(y)
when I peform the insert usually do this: Date.Now.ToString("yyyy-MM-dd HH:mm:ss") so I apply a format to date to insert... if I don't format correctly the date as I shown I get this value 0000-00-00 00:00:00
That doesn't apply a format to a date. It converts the DateTime to a string. While "yyyy-MM-dd HH:mm:ss" is the correct format to use when passing date data as a string to MySql, it is not needed. The MySQL Data provider knows how to convert a Net DateTime var to the data MySql needs/wants and back again -- that's its job.
' this will work fine
cmd.Parameters.Add("#SomeDate", MySqlDbType.DateTime).Value = myDateTimeVar
The format requirement you read about is the what you need to use in the MySql shell or WorkBench UI because you are entering text/string there...from the keyboard. It does not mean code must convert DateTime variables to string in a specific format for storing.
I ended up using this
Try
Dim theDate As DateTime = dr.Item(colName)
Return theDate
Catch
' do something
End Try
I would be happy to see a better method.
Based off of what you seem to be asking a simple replace would do
For z = 1 To ds.Tables(0).Columns.Count - 1
Console.WriteLine(ds.Tables(0).Rows(x)(z).ToString().Replace("/","-"))
Next
if it comes in with / they are changed to - if it comes in with - they remain intact.
Depending on the flexibility you want in this, it may be necessary to TryParse to ensure that the value you're working with is actually a valid datetime.

How to display datetime form mysql using CakePHP 3.0

I would like to ask how to add datetime ('Y-m-d h:i:s') format field for the SQL.
The name of my table is groups, the name of the field is date_add
i am using cake PHP 3, i want to use the timezone Australia/Perth but i don't know how to begin.
I successfully displayed added my date using
$group->date_add = date("Y-m-d h:i:s");
However, the result for the time is not correct with the timezone.
Datetime in PHP in general
Per the documentation of DateTime you can use all options available for the date() functions for formatting. Your main mistake in the formatting is the difference betweetn a y and a Y being the difference between a year in two and a year in four numbers.
Secondly you say you want to add the correct time zone. This is a bit odd however since you always want to add the same time zone. If you want to convey the fact that all your dates are Australia/Perth as information why do you not simply add that text after it?
If you mean this is a problem since you store the information in a different time zone to begin with and thus have a conversion problem you can set the correct time zone on the DateTime object itself. But you need to be sure the DateTime object is constructed with the correct original time zone to begin with. Observe the following code for an explanation:
<?php
$DateTime = new DateTime(); // This is now Europe/Amsterdam for my laptop
var_dump($DateTime->format('dmY h:i e'));
// result of var_dump is: string(31) "13102015 12:00 Europe/Amsterdam"
$DateTime->setTimeZone(new DateTimeZone('Europe/London'));
var_dump($DateTime->format('dmY h:i e'));
// result of var_dump is: string(28) "13102015 11:00 Europe/London"
Take aways:
e is the format modifier for the time zone
Conversion of time zones is possible with PHP's DateTime object. Find out what your default time zone is on your current PHP installation to see if you need to convert or not. See information on the date.timezone setting here: http://php.net/manual/en/datetime.configuration.php
Cake 3.0 specific
As Oops D'oh pointed out in the comments there are a lot of CakePHP specific things to know as well. Since he added an excellent part concerning that I suggest you read that as well.

How can I store the date to the table without a time stamp?

I am in a form, using Short Date format (I have tried General, Long, Medium) - each stores a time stamp along with the date in the table. like x/xx/xxxx hr:min:ss am/pm.
This should be so simple.
As noted in the comments to your question, values in Access Date/Time columns always have both a date and a time component. However, in most cases Access will display only the date part if the time is exactly midnight, so if you force the time to midnight when storing the value then it will look like a date-only value.
By changing the Date value to Integer you can hide the time portion of the Date and Time.
Example:
dValue = Now() shows Date and Time
dValue = Int(Now()) shows only the Date

How to subtract certain minuted from a DateTime in SPSS

I have timestamps in a column which I have imported in SPSS. Example, 7/6/2011 2:21 in a column called 'Observation'
This is in the string format. Now I also have timezone corrections for these data. So, -60 would mean subtract 60 minutes from this date.
How would I do this in SPSS syntax?
There are native date formats in SPSS, but unfortunately it does not appear that any cover the example you posted. I would parse the beginning of the string field to get the mm/dd/yyyy and the hh:mm part seperate, convert those into their representative time formats, and then do the time calculations.
For an example
data list fixed / observation (A25).
begin data
7/6/2011 2:21
10/11/2011 15:42
07/06/2011 02:21
3/15/2011 0:21
end data.
*getting the data part, assuming the space will always delimit the two parts.
compute #space = char.index(observation," ").
string date (A10).
compute date = char.substr(observation,1,#space-1).
*getting the time part.
string time (A5).
compute time = char.substr(observation,#space+1,5).
execute.
*now converting them into date formats.
alter type date (A10 = ADATE10).
alter type time (A5 = TIME5).
*you should check these carefully to make sure they were converted correctly.
*now making one time variable.
compute date_time = date + time.
formats date_time (DATETIME17).
execute.
*now it is just as simple as subtracting the specified value.
compute date_time_adj = DATESUM(date_time,-60,"minutes").
execute.
formats date_time_adj (DATETIME17).