i have a complex problem with Date field. Describe what i want to do:
I have field date1 as Date in my db.
#Temporal(TemporalType.DATE)
private Date date1;
I want to take data from this field and compare with current date.
#Query("SELECT date1 FROM Table io WHERE io.date1 >= DATE_FORMAT(CURRENT_DATE, '%Y-%m-%e')")
Date findAll2();
public boolean CheckDate1(){
currentDate = new Date();
date1 = getInterimOrdersRepo().findAll2();
if(currentDate.before(date1) || currentDate.equals(date1)){
System.out.println("TRUE");
System.out.println("currentDate = "+currentDate);
return true;
}
else{
System.out.println("FALSE");
return false;
}
}
but i have an error:
result returns more than one elements; nested exception is javax.persistence.NonUniqueResultException
When method return false i want do Update field data1 with " " empty data.
I using jsf, what i must to do?
It seems that you are trying to read several values from the table into a single variable, and that is the error.
findall2 returns an array (most likely) and u should read one of it's values - try reading first one.
Furthermore, I believe that you can skip the "DATE_FORMAT" in your query, and this is a very strange way to write a code. Not clear what u are trying to achieve here
Currently when I need to run a query that will be used w/ paging I do it something like this:
//Setup query (Typically much more complex)
var q = ctx.People.Where(p=>p.Name.StartsWith("A"));
//Get total result count prior to sorting
int total = q.Count();
//Apply sort to query
q = q.OrderBy(p => p.Name);
q.Select(p => new PersonResult
{
Name = p.Name
}.Skip(skipRows).Take(pageSize).ToArray();
This works, but I wondered if it is possible to improve this to be more efficient while still using linq? I couldn't think of a way to combine the count w/ the data retrieval in a single trip to the DB w/o using a stored proc.
The following query will get the count and page results in one trip to the database, but if you check the SQL in LINQPad, you'll see that it's not very pretty. I can only imagine what it would look like for a more complex query.
var query = ctx.People.Where (p => p.Name.StartsWith("A"));
var page = query.OrderBy (p => p.Name)
.Select (p => new PersonResult { Name = p.Name } )
.Skip(skipRows).Take(pageSize)
.GroupBy (p => new { Total = query.Count() })
.First();
int total = page.Key.Total;
var people = page.Select(p => p);
For a simple query like this, you could probably use either method (2 trips to the database, or using GroupBy to do it in 1 trip) and not notice much difference. For anything complex, I think a stored procedure would be the best solution.
Jeff Ogata's answer can be optimized a little bit.
var results = query.OrderBy(p => p.Name)
.Select(p => new
{
Person = new PersonResult { Name = p.Name },
TotalCount = query.Count()
})
.Skip(skipRows).Take(pageSize)
.ToArray(); // query is executed once, here
var totalCount = results.First().TotalCount;
var people = results.Select(r => r.Person).ToArray();
This does pretty much the same thing except it won't bother the database with an unnecessary GROUP BY. When you are not certain your query will contain at least one result, and don't want it to ever throw an exception, you can get totalCount in the following (albeit less cleaner) way:
var totalCount = results.FirstOrDefault()?.TotalCount ?? query.Count();
Important Note for People using EF Core >= 1.1.x && < 3.0.0:
At the time I was looking for solution to this and this page is/was Rank 1 for the google term "EF Core Paging Total Count".
Having checked the SQL profiler I have found EF generates a SELECT COUNT(*) for every row that is returned. I have tired every solution provided on this page.
This was tested using EF Core 2.1.4 & SQL Server 2014. In the end I had to perform them as two separate queries like so. Which, for me at least, isn't the end of the world.
var query = _db.Foo.AsQueryable(); // Add Where Filters Here.
var resultsTask = query.OrderBy(p => p.ID).Skip(request.Offset).Take(request.Limit).ToArrayAsync();
var countTask = query.CountAsync();
await Task.WhenAll(resultsTask, countTask);
return new Result()
{
TotalCount = await countTask,
Data = await resultsTask,
Limit = request.Limit,
Offset = request.Offset
};
It looks like the EF Core team are aware of this:
https://github.com/aspnet/EntityFrameworkCore/issues/13739
https://github.com/aspnet/EntityFrameworkCore/issues/11186
I suggest making two queries for the first page, one for the total count and one for the first page or results.
Cache the total count for use as you move beyond the first page.
I have the following problem: In our database we record helpdesk tickets and we book hours under tickets. Between those is a visit report. So it is: ticket => visitreport => hours.
Hours have a certain 'kind' which is not determined by a type indicator in the hour record, but compiled by checking various properties of an hour. For example, an hour which has a customer but is not a service hour is always an invoice hour.
Last thing I want is that the definitions of those 'kinds' roam everywhere in the code. They must be at one place. Second, I want to be able to calculate totals of hours from various collections of hours. For example, a flattened collection of tickets with a certain date and a certain customer. Or all registrations which are marked as 'solution'.
I have decided to use a 'layered' database access approach. The same functions may provide data for screen representation but also for a report in .pdf . So the first step gathers all relevant data. That can be used for .pdf creation, but also for screen representation. In that case, it must be paged and ordered in a second step. That way I don't need separate queries which basically use the same data.
The amount of data may be large, like the creation of year totals. So the data from the first step should be queryable, not enumerable. To ensure I stay queryable even when I add the summation of hours in the results, I made the following function:
public static decimal TreeHours(this IEnumerable<Uren> h, FactHourType ht)
{
IQueryable<Uren> hours = h.AsQueryable();
ParameterExpression pe = Expression.Parameter(typeof(Uren), "Uren");
Expression left = Expression.Property(pe, typeof(Uren).GetProperty("IsOsab"));
Expression right = Expression.Constant(true, typeof(Boolean));
Expression isOsab = Expression.Equal(Expression.Convert(left, typeof(Boolean)), Expression.Convert(right, typeof(Boolean)));
left = Expression.Property(pe, typeof(Uren).GetProperty("IsKlant"));
right = Expression.Constant(true, typeof(Boolean));
Expression isCustomer = Expression.Equal(Expression.Convert(left, typeof(Boolean)), Expression.Convert(right, typeof(Boolean)));
Expression notOsab;
Expression notCustomer;
Expression final;
switch (ht)
{
case FactHourType.Invoice:
notOsab = Expression.Not(isOsab);
final = Expression.And(notOsab, isCustomer);
break;
case FactHourType.NotInvoice:
notOsab = Expression.Not(isOsab);
notCustomer = Expression.Not(isCustomer);
final = Expression.And(notOsab, notCustomer);
break;
case FactHourType.OSAB:
final = Expression.And(isOsab, isCustomer);
break;
case FactHourType.OsabInvoice:
final = Expression.Equal(isCustomer, Expression.Constant(true, typeof(Boolean)));
break;
case FactHourType.Total:
final = Expression.Constant(true, typeof(Boolean));
break;
default:
throw new Exception("");
}
MethodCallExpression whereCallExpression = Expression.Call(
typeof(Queryable),
"Where",
new Type[] { hours.ElementType },
hours.Expression,
Expression.Lambda<Func<Uren, bool>>(final, new ParameterExpression[] { pe })
);
IQueryable<Uren> result = hours.Provider.CreateQuery<Uren>(whereCallExpression);
return result.Sum(u => u.Uren1);
}
The idea behind this function is that it should remain queryable so that I don't switch a shipload of data to enumerable.
I managed to stay queryable until the end. In step 1 I gather the raw data. In step 2 I order the data and subsequently I page it. In step 3 the data is converted to JSon and sent to the client. It totals hours by ticket.
The problem is: I get one query for the hours for each ticket. That's hundreds of queries! That's too much...
I tried the following approach:
DataLoadOptions options = new DataLoadOptions();
options.LoadWith<Ticket>(t => t.Bezoekrapport);
options.LoadWith<Bezoekrapport>(b => b.Urens);
dc.LoadOptions = options;
Bezoekrapport is simply Dutch for 'visitreport'. When I look at the query which retrieves the tickets, I see it joins the Bezoekrapport/visitreport but not the hours which are attached to it.
A second approach I have used is manually joining the hours in LINQ, but that does not work as well.
I must do something wrong. What is the best approach here?
The following code snippets are how I retrieve the data. Upon calling toList() on strHours in the last step, I get a hailstorm of queries. I've been trying for two days to work around it but it just doesn't work... Something must be wrong in my approach or in the function TreeHours.
Step 1:
IQueryable<RelationHoursTicketItem> HoursByTicket =
from Ticket t in allTickets
let RemarkSolved = t.TicketOpmerkings.SingleOrDefault(tr => tr.IsOplossing)
let hours = t.Bezoekrapport.Urens.
Where(h =>
(dateFrom == null || h.Datum >= dateFrom)
&& (dateTo == null || h.Datum <= dateTo)
&& h.Uren1 > 0)
select new RelationHoursTicketItem
{
Date = t.DatumCreatie,
DateSolved = RemarkSolved == null ? (DateTime?)null : RemarkSolved.Datum,
Ticket = t,
Relatie = t.Relatie,
HoursOsab = hours.TreeHours(FactHourType.OSAB),
HoursInvoice = hours.TreeHours(FactHourType.Invoice),
HoursNonInvoice = hours.TreeHours(FactHourType.NotInvoice),
HoursOsabInvoice = hours.TreeHours(FactHourType.OsabInvoice),
TicketNr = t.Id,
TicketName = t.Titel,
TicketCategorie = t.TicketCategorie,
TicketPriority = t.TicketPrioriteit,
TicketRemark = RemarkSolved
};
Step 2
sort = sort ?? "TicketNr";
IQueryable<RelationHoursTicketItem> hoursByTicket = GetRelationHours(relation, dateFrom, dateTo, withBranches);
IOrderedQueryable<RelationHoursTicketItem> orderedResults;
if (dir == "ASC")
{
orderedResults = hoursByTicket.OrderBy(sort);
}
else
{
orderedResults = hoursByTicket.OrderByDescending(sort);
}
IEnumerable<RelationHoursTicketItem> pagedResults = orderedResults.Skip(start ?? 0).Take(limit ?? 25);
records = hoursByTicket.Count();
return pagedResults;
Step 3:
IEnumerable<RelationHoursTicketItem> hours = _hourReportService.GetRelationReportHours(relation, dateFrom, dateTo, metFilialen, start, limit, dir, sort, out records);
var strHours = hours.Select(h => new
{
h.TicketNr,
h.TicketName,
RelationName = h.Relatie.Naam,
h.Date,
TicketPriority = h.TicketPriority.Naam,
h.DateSolved,
TicketCategorie = h.TicketCategorie == null ? "" : h.TicketCategorie.Naam,
TicketRemark = h.TicketRemark == null ? "" : h.TicketRemark.Opmerking,
h.HoursOsab,
h.HoursInvoice,
h.HoursNonInvoice,
h.HoursOsabInvoice
});
I don't think your TreeHours extension method can be converted to SQL by LINQ in one go. So are evaluated on execution of each constructor of the row, causing a 4 calls to the database in this case per row.
I would simplfy your LINQ query to return you the raw data from SQL, using a simple JOIN to get all tickets and there hours. I would then group and filter the Hours by type in memory. Otherwise, if you really need to perform your operations in SQL then look at the CompiledQuery.Compile method. This should be able to handle not making a query per row. I'm not sure you'd get the switch in there but you may be able to convert it using the ?: operator.
I am using the following code to update the UserSession column of the Activities. Following code return the records if the ExpiryTimeStamp is less then current date.
Then it Update the UserSession column to 0 for the returned recods in the table.
.Now I wants that if there are 100 records are returned then these should update at one time instead of using the FoREach. Is it posible in Linq
CacheDataDataContext db = new CacheDataDataContext();
var data = (from p in db.Activities
where p.ExpiryTimeStamp < DateTime.Now
select p).ToList();
data.ForEach(ta => ta.UserSession = "0");
db.SubmitChanges();
In short, no: Linq-2-sql does not do batch updates out of the box.
(I am not sure your foreach will work like you wrote - i do not think so - but this is similar and will work)
foreach (var x in data)
{x.UserSession = "0";}
db.SubmitChanges()
BUT, even if you do it like this, Linq-2-sql will send an update statement for each record to the database. So with your example of 100 records returned you will get 100 individual updates send to the database.
I'm using the latest subsonic dll and the latest linq templates from github. The db i'm inserting into is MySQL. Id column on table is primary key auto increment.
Versions:
Subsonic.Core.dll - 3.0.0.3 - (November 18, 2009 Merged pulls from Github).
LinqTemplates - July 29, 2009.
MySQL.Data.CF.dll - 6.1.2.0.
The row is inserted but the id is returned as 0.
Example of the insert:
mysqldb db = new mysqldb.mysqldbDB();
int ID = db.Insert.Into<db.myTable>(
r => r.message,
r => r.name,
r => r.status).Values(
message,
name,
status).Execute();
Am I doing something wrong? Shouldn't the new id be returned, not zero?
Found the bug in subsonic core.
It's in Subsonic.Core.Query.Insert.cs
The Execute method does not have a condition for id's returned that are of type long.
I've rewritten the method in my local version to:
public int Execute()
{
int returner = 0;
object result = _provider.ExecuteScalar(GetCommand());
if(result != null)
{
if(result.GetType() == typeof(decimal))
returner = Convert.ToInt32(result);
else if (result.GetType() == typeof(int))
returner = Convert.ToInt32(result);
else if (result.GetType() == typeof(long))
returner = Convert.ToInt32(result);
else
returner = Convert.ToInt32(result);
}
return returner;
}
I've changed the multiple if statements to else if's and added the type comparison of long. Also I've added the final else condition which does a convert to int. Not sure if that's such a good idea but it works for me.
If someone wants to update the source great. If i find time sometime soon i'll update it myself.