I am trying to compare a date to a datetime field in SQL. I try this:
Dim entry = db.Tbl_Hydrations.Where(Function(x) x.Hyd_Create_Date.Date = _date1)
However, the error I get is:
The specified type member 'Date' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported.
On line:
If entry.Any Then
Seems like LINQ to Entities doesn't support the Date property. You could try doing a comparison between two dates as a workaround:
Dim nextDay As DateTime = _date1.AddDays(1)
Dim entry = db.Tbl_Hydrations.Where(Function(x) x.Hyd_Create_Date >= _date1 AndAlso x.Hyd_Create_Date < nextDay)
not sure of the syntax (not a vb man, but you can use canonical functions)
Dim entry = db.Tbl_Hydrations
.Where(Function(x) EntityFunctions.CreateDateTime
(x.Hyd_Create_Date.Year, x.Hyd_Create_Date.Month, x.Hyd_Create_Date.Day, 0, 0, 0) = _date1);
Related
I am trying to get the latest date based on my controller below but I was hit with this error :
"Unable to cast object of type 'System.Data.Entity.Infrastructure.DbQuery1[<>f__AnonymousType201[System.Nullable`1[System.DateTime]]]' to type 'System.IConvertible'."
var latestDt = from n in db.Books
where n.id == id
select new { Date = n.dtBookBorrowed};
DateTime dtPlus1Year = Convert.ToDateTime(latestDt);
May I know how do I get just the column latestDate in linq?
You can try this to get list of date order by latest insert to db.
var latestDt = db.Books.Where(n => n.id == id).OrderByDescending(x => x.dtBookBorrowed).Select(x => x.dtBookBorrowed).ToList();
I think if you use
DateTime.Parse(item.dateAsString)
your problem should be solved.
The LINQ query expression you've defined returns a collection of anonymous object with property Date despite there might be only one record match as ID was meant to be unique.
In your case we only need the target field that can be parsed as DateTime and therefore an alternative in fluent syntax would be as following:-
var book = db.Books.SingleOrDefault(book => book.id == id); // gets matching book otherwise null
if (book != null)
{
var borrowedDate = Convert.ToDateTime(book.dtBookBorrowed);
}
Otherwise if you would like to understand more about the behaviour with query syntax which may return multiple results, you may simplify as following which returns collection of DateTime object (i.e. IEnumerable) instead:-
IEnumerable<DateTime> borrowedDates =
from n in db.Books
where n.id == id
select Convert.ToDateTime(n.dtBookBorrowed);
I'm trying to return a count of records from a database with today's date, using entity framework. I think my query is ok, if you take a look at the screenshot record 2 is the only item out of the 3 with todays date, which is correct.
How can i return a count. Currently its returning a bool value
Thank you
Dim today = DateTime.Today.Date
Dim todaysBuild = retrieveOrders.[Select](Function(build) build.TimeAndDate >= today).ToList()
EDIT:
Dim todaysBuild = retrieveOrders.Where(Function(build) build.TimeAndDate >= today).ToList()
The variable todaysBuild is a list. You need the count (Integer) of that list so add the .Count at the end of your code.
Dim todaysBuild = retrieveOrders.[WHERE](Function(build) build.TimeAndDate >= today).ToList.Count
I'm having some trouble working with dates.
I have an object with a date field:
public DateTime FechaInicio{get; set;}
This definition generates the following field in the database:
FechaInicio datetime not null
Making the request to the web service I get the date ( in the JSON ) in the following format:
"FechaInicio": "1982-12-02T00: 00:00"
And calling FechaInicio() on tne entity returns a javascript Date object.
Creating a new entity I get the following value:
createPalanca var = function () {
MetadataStore var = manager.metadataStore;
metadataStore.getEntityType palancaType = var ("Toggle");
palancaType.createEntity newPalanca = var ();
manager.addEntity (newPalanca);
//Here: newPalanca.FechaInicio () has the value in this format: 1355313343214
//Expected Date object here
newPalanca return;
};
After all, my real question is: What format should I use to assign new values to date type fields?
Edit:
After doing some tests, I noticed that if I assign a Date object to the property, everything seems fine until we got to this line:
saveBundleStringified var = JSON.stringify (saveBundle);
saveBundle content is:
FechaInicio: Thu Dec 20 2012 00:00:00 GMT+0100 (Hora estándar romance)
and the saveBundleStringified:
"FechaInicio": "2012-12-19T23:00:00.000Z" <- I guess this is utc format
What finally is stored in the database is: 2012-12-19 23:00:00.0000000
When the result of the call to SaveChanges are returned , they are merged with the entities in cache at the function updateEntity which does this check: if (!core.isDate(val)) that returns false.
As a consequence it is created a new Date object with the wrong date:
function fastDateParse(y, m, d, h, i, s, ms){ //2012 12 19 23 00 00 ""
return new Date(y, m - 1, d, h || 0, i || 0, s || 0, ms || 0);
}
Correct me if I'm wrong, but I think that's the problem.
Sorry for taking so long...
There were bugs with Breeze's DateTime timezone serialization and the default DateTime values used for newly constructed entities with non-nullable date fields. These are fixed as of v 0.77.2. Please confirm if this set of fixes works for you.
And thanks for finding these.
And to answer your question, all date properties on your object should be set to javascript Dates. Breeze should handle all of the serialization issues properly.
Dates always scare me. My immediate instinct is that the browser and server are not on the same TimeZone; how that could be I don't know. In any case, it's bound to happen and I recall all kinds of fundamental problems with coordinating client and server on datetime. I think the usual recommendation has always been to keep everything in UTC and adjust what you display to the user in local time.
I rather doubt this is a helpful answer. I'm not sure what part Breeze should play in resolving this. Would welcome a suggestion that we can circulate and build consensus around.
Also can you clarify this statement:
When the result of the call to SaveChanges are returned , they are merged with the entities in cache at the function updateEntity which does this check: if (!core.isDate(val)) that returns false. As a consequence it is created a new Date object with the wrong date
What do you mean by "the wrong date"? And are you saying that Breeze thinks the incoming date value is in an invalid format (as opposed to being a date other than the one you expected)?
Yes, #Sascha, Breeze is using the Web Api standard for JSON formatting (Json.Net) and it is set for ISO8601 format as opposed to the wacky Microsoft format (which escapes me as I write this).
Breeze/Web Api seem to need the dates in some special format (ISO8601). Any other format did not work for me. moment.js solved the problem for me with setting and reading. Formatting is also nicely done if you use Knockout to display the date with a special binding.
entity.someDate(moment().utc().toDate()) // example
and it works.
You could also use this:
Date.prototype.setISO8601 = function(string) {
var regexp = "([0-9]{4})(-([0-9]{2})(-([0-9]{2})" +
"(T([0-9]{2}):([0-9]{2})(:([0-9]{2})(\.([0-9]+))?)?" +
"(Z|(([-+])([0-9]{2}):([0-9]{2})))?)?)?)?";
var d = string.match(new RegExp(regexp));
var offset = 0;
var date = new Date(d[1], 0, 1);
if (d[3]) {
date.setMonth(d[3] - 1);
}
if (d[5]) {
date.setDate(d[5]);
}
if (d[7]) {
date.setHours(d[7]);
}
if (d[8]) {
date.setMinutes(d[8]);
}
if (d[10]) {
date.setSeconds(d[10]);
}
if (d[12]) {
date.setMilliseconds(Number("0." + d[12]) * 1000);
}
if (d[14]) {
offset = (Number(d[16]) * 60) + Number(d[17]);
offset *= ((d[15] == '-') ? 1 : -1);
}
offset -= date.getTimezoneOffset();
time = (Number(date) + (offset * 60 * 1000));
this.setTime(Number(time));
};
I'm trying to do a compiled query but I just want it to return an int
public Func<DataContext, DateTime, int>
GetNextTourNo = CompiledQuery.Compile((DataContext db, DateTime day) => ((from b in db.GetTable<BookingType>()
where b.RecordType == "H" && b.TourStartDateTime.Value.Date == day.Date
orderby b.TourID descending
select new { nextID = b.TourID +1 }).Single()));
You could just return nextID property from selected single anonymous object
select new { nextID = b.TourID +1 }).Single().nextID
Can you provide a bit more information on the anonymous type and the context of the compiled query?
Also if you are using the query directly in linq to Entity the date comparison will not work. Entity Functions need to be used for this. This could cause the invalid return.
I have the following SQL command:
SELECT CONVERT(varchar, Logged, 103) AS Visited, COUNT(ID) AS Totals
FROM tblStats
GROUP BY CONVERT(varchar, Logged, 103)
ORDER BY Visited DESC
I want to translate this into a L2S statement that can be used with the Entity Framework, but in working with datetime types, I'm getting various errors depending on how I try to attack the problem.
Approach:
var results = from s in db.Stats
group s by (s.Logged.Date.ToString()) into Grp
select new { Day = Grp.Key, Total = Grp.Count() };
Error:
LINQ to Entities does not recognize
the method 'System.String ToString()'
method, and this method cannot be
translated into a store expression.
Approach:
var results = from s in db.Stats
group s by (s.Logged.Date) into Grp
select new { Day = Grp.Key, Total = Grp.Count() };
Error:
The specified type member 'Date' is
not supported in LINQ to Entities.
Only initializers, entity members, and
entity navigation properties are
supported.
What syntax do I need to make the query work?
Try using the EntityFunctions.TruncateTime method:
var results = from s in db.Stats
group s by EntityFunctions.TruncateTime(s.Logged) into Grp
select new { Day = Grp.Key, Total = Grp.Count() };
Do you need the Date section in s.Logged.Date?
Have you tried this:
var results = from s in db.Stats
group s by (s.Logged) into Grp
select new { Day = Grp.Key, Total = Grp.Count() };
I'm assuming that Logged is the property (column in the table).
EDIT: you guys are way to quick.