I'm working with a legacy Oracle database that has a column on a table which stores boolean values as 'Y' or 'N' characters.
I have mapped/converted this column out like so:
MappingSchema.Default.SetConverter<char, bool>(ConvertToBoolean);
MappingSchema.Default.SetConverter<bool, char>(ConvertToChar);
ConvertToBoolean & ConvertToChar are simply functions that map between the types.
Here's the field:
private char hasDog;
[Column("HAS_DOG")]
public bool HasDog
{
get => ConvertToBoolean(hasDog);
set => hasDog = ConvertToChar(value);
}
This has worked well for simply retrieving data, however, it seems the translation of the following:
var humanQuery = (from human in database.Humans
join vetVisit in database.VetVisits on human.Identifier equals vetVisit.Identifier
select new HumanModel(
human.Identifier
human.Name,
human.HasDog,
vetVisit.Date,
vetVisit.Year,
vetVisit.PaymentDue
));
// humanQuery is filtered by year here
var query = from vetVisits in database.VetVisits
select new VetPaymentModel(
(humanQuery).First().Year,
(humanQuery).Where(q => q.HasDog).Sum(q => q.PaymentDue), -- These 2 lines aren't correctly translated to Y/N
(humanQuery).Where(q => !q.HasDog).Sum(q => q.PaymentDue)
);
As pointed out above, the .Where clause here doesn't translate the boolean comparison of HasDog being true/false to the relevant Y/N values, but instead a 0/1 and results in the error
ORA-01722: invalid number
Is there any way to handle this case? I'd like the generated SQL to check that HAS_DOG = 'Y' for instance with the specified Where clause :)
Notes
I'm not using EntityFramework here, the application module that this query exists in doesn't use EF/EFCore
You can define new mapping schema for your particular DataConnection:
var ms = new MappingSchema();
builder = ms.GetFluentMappingBuilder();
builder.Entity<Human>()
.Property(e => e.HasDog)
.HasConversion(v => v ? 'Y' : 'N', p => p == 'Y');
Create this schema ONCE and use when creating DataConnection
Related
How can i dynamically change the selected columns in the generated sql query when using a linq expression?
Its a new session for each time the query is executed.
Even when I set the MapExp as null after first creation an then changing the bool value to false, it still generates the column in the sql query.
The code runs in a wpf application.
System.Linq.Expressions.Expression<Func<Entity, Model>> MapExp = x => new Model
{
Id=xId,
Count= LoadFormulaField ? x.Count: null,
...
};
var result = session.Query<Entity>().Select(MapExp))
Your problem seems to be the ternary-conditional as part of the expression which is causing the "Count" column to always be queried.
One option to avoid this could be:
var query = session.Query<Entity>();
IQueryable<Model> result = null;
if (LoadFormulaField)
{
result = query.Select(x => new Model
{
Id = x.Id,
Count = x.Count,
});
}
else
{
result = query.Select(x => new Model
{
Id = x.Id,
});
}
Which would get a little less ugly if you separate in a couple of methods I think.
I'm calling the sql server function Contains like this :
ftquery = _OrElse(ftquery,Restrictions.Eq(Projections.SqlFunction("contains",NHibernateUtil.Boolean, Projections.Property<Document>(d => d.SearchContent), Projections.Constant(query.Query)),true));
OrElse will juste do an or using Restrictions.Or(ICriterion, ICriterion). The problem is that it generates invalid sql :
... and contains(this_.SearchContent, ?) = ? ORDER BY ...
I don't want to have the right part ( = ? ), I only need the Projection without the Restrictions.Eq, but without Restrictions.Eq I can't find any solution to convert a Projection to a Criterion.
How can we using NHibernate generate an sql like :
Select Name from Users where Contains(Name,'toto') or Contains(Job,'tata')
Register the function in your dialect:
RegisterFunction("FullTextContains", new StandardSQLFunction("contains", NHibernateUtil.Boolean));
Create a projection using Projections.SqlFunction then use this ProjectionAsCriterion class on your query:
var projection = Projections.SqlFunction("FullTextContains",
NHibernateUtil.Boolean,
Projections.Property<Document>(x => x.SearchContent),
Projections.Constant(query.Query));
var result = Session.QueryOver<Document>()
.Where(new ProjectionAsCriterion(projection))
.List();
Really stuck with Linq to SQL grouping and summing, have searched everywhere but I don't understand enough to apply other solutions to my own.
I have a view in my database called view_ProjectTimeSummary, this has the following fields:
string_UserDescription
string_ProjectDescription
datetime_Date
double_Hours
I have a method which accepts a to and from date parameter and first creates this List<>:
List<view_UserTimeSummary> view_UserTimeSummaryToReturn =
(from linqtable_UserTimeSummaryView
in datacontext_UserTimeSummary.GetTable<view_UserTimeSummary>()
where linqtable_UserTimeSummaryView.datetime_Week <= datetime_To
&& linqtable_UserTimeSummaryView.datetime_Week >= datetime_From
select linqtable_UserTimeSummaryView).ToList<view_UserTimeSummary>();
Before returning the List (to be used as a datasource for a datagridview) I filter the string_UserDescription field using a parameter of the same name:
if (string_UserDescription != "")
{
view_UserTimeSummaryToReturn =
(from c in view_UserTimeSummaryToReturn
where c.string_UserDescription == string_UserDescription
select c).ToList<view_UserTimeSummary>();
}
return view_UserTimeSummaryToReturn;
How do I manipulate the resulting List<> to show the sum of the field double_Hours for that user and project between the to and from date parameters (and not separate entries for each date)?
e.g. a List<> with the following fields:
string_UserDescription
string_ProjectDescription
double_SumOfHoursBetweenToAndFromDate
Am I right that this would mean I would have to return a different type of List<> (since it has less fields than the view_UserTimeSummary)?
I have read that to get the sum it's something like 'group / by / into b' but don't understand how this syntax works from looking at other solutions... Can someone please help me?
Thanks
Steve
Start out by defining a class to hold the result:
public class GroupedRow
{
public string UserDescription {get;set;}
public string ProjectDescription {get;set;}
public double SumOfHoursBetweenToAndFromDate {get;set;}
}
Since you've already applied filtering, the only thing left to do is group.
List<GroupedRow> result =
(
from row in source
group row by new { row.UserDescription, row.ProjectDescription } into g
select new GroupedRow()
{
UserDescription = g.Key.UserDescription,
ProjectDescription = g.Key.ProjectDescription,
SumOfHoursBetweenToAndFromDate = g.Sum(x => x.Hours)
}
).ToList();
(or the other syntax)
List<GroupedRow> result = source
.GroupBy(row => new {row.UserDescription, row.ProjectDescription })
.Select(g => new GroupedRow()
{
UserDescription = g.Key.UserDescription,
ProjectDescription = g.Key.ProjectDescription,
SumOfHoursBetweenToAndFromDate = g.Sum(x => x.Hours)
})
.ToList();
How to convert the following sql query to lambda expression?
select cg.Code, ci.ChangeType, SUM(oc.Value) from OtherCharges oc
left join changeitems ci on oc.ChangeItemKey = ci.ChangeItemKey
left join ChangeGroups cg on ci.ChangeGroupKey = cg.ChangeGroupKey
where OtherKey = 'AB235A00-FEB2-4C4F-B0F9-3239FD127A8F'
group by cg.Code, ci.ChangeType
order by cg.Code, ci.ChangeType
Assuming you already have .NET domain types for your tables:
IQueryable<OtherCharges> otherCharges = ...
Guid otherKey = ...
var query = otherCharges.Where(oc => oc.OtherKey == otherKey)
.Select(oc => new { oc.ChangeItem, oc.Value })
.GroupBy(t => new { t.ChangeItem.ChangeGroup.Code, t.ChangeItem.ChangeType })
.OrderBy(g => g.Key.Code)
.ThenBy(g => g.Key.ChangeType)
// note that if Code is a non-nullable type you'll want to cast it to int? at some
// point so that when pulled into memory EF won't complain that you can't cast
// null to a non-nullable type. I expect that Code could sometimes be null here
// do to your use of LEFT OUTER JOIN in the T-SQL
.Select(g => new { g.Key.Code, g.Key.ChangeType, Sum = g.Sum(t => t.Value) });
var inMemoryResult = query.ToList();
Note that I'm using OtherCharge.ChangeItem and ChangeItem.ChangeGroup here. These are association properties and need to be set up as part of your model (e. g. using fluent configuration for EF code first).
My problem is:
I would like to get all advertistments where id of Description column is equals with Advertistment's column.
Let's say that Advertistment column is connected with Description column.
I would like to gain all description's id where one of its column called type_of_house is equals m.
Then show all advertistment where advertistment's id is equals with description's id.
In short way: advertistment shows info about houses, descriptions store houses type D and M and I want show all advertistments with houses type of M.
This is correct sql:
SELECT * FROM advertistment, description WHERE advertistment.id_advertistment = description.id_description AND description.type_of_house = "m"
I have no idea how write it into zend. I tried something like that. This function I wrote in model folder.
public function takeAll() {
$select = $this->_db->select();
$select->from(array('a' => 'advertistment', 'd' => 'description'));
$select->where('a.id_advertistment = d.id_description AND d.type_of_house = m');
return $select->query()->fetchAll();
}
You're actually quite close. This should work:
public function takeAll() {
$select = $this->_db->select();
$select->from(array('a' => 'advertistment'));
$select->join(array('d' => 'description'), 'a.id_advertistment = d.id_description');
$select->where('d.type_of_house = ?', 'm');
return $this->_db->fetchAll($select);
}