Please assume the following mapping
Class PieChart{
#Persistent(defaultFetchGroup = "true", table = "chart_metrics_rel")
#Join(column = "chart_fk")
#Order(column = "order")
#Element(dependent = "true", column = "chart_metric_fk")
#Extensions({ #Extension(vendorName = "datanucleus", key = "relation-discriminator-column", value = "chart_type"),
#Extension(vendorName = "datanucleus", key = "relation-discriminator-pk", value = "true"),
#Extension(vendorName = "datanucleus", key = "relation-discriminator-value", value = "pie") })
private List<ChartMetric> metrics;
}
This works as expected but the problem is that I have the same exact mapping with another class called TimeseriesChart which have a whole another table with different id's. So the chart_fk column in the mapping shown above may sometimes point to PieChart and some other times point to TimeseriesChart. So the shared join table is created with 2 foreign-keys on the chart_fk column, once pointing to pie_charts (i.e. PieChart, the current class) and once pointing to the timeseries_chart (i.e. TimeseriesChart).
Which is not allowing me to add elements to the join table unless the chart_fk value exists in both the pie and timeseries tables !
I checked the docs and used the generateForeignKey annotation attribute for #Join but it isn't working.
That's the attribute's description:
generateForeignKey (String) ORM:Whether to generate a FK constraint on the join table (when not specifying the name)
So why does the attribute has no effect as the foreign-keys are still generated ?
And what name is when not specifying the name referring to ? the join table's or the FK's ?
Since that vendor extension clearly applies to sharing a join table between relations to the same type (as per what the DN docs show), then you're trying to apply it where it is not intended, hence user-error.
If you have two List<Chart> fields and one has one subclass (PieChart), and the other a different subclass (TimeseriesChart) then it is potentially applicable there (all of our tests are based around Collections of the same element type), but you present no such information.
Related
I have created a CDS views as follows:
define view YGAC_I_REQUEST_ROLE
with parameters
pm_req_id : grfn_guid,
#Consumption.defaultValue: 'ROL'
pm_item_type : grac_prov_item_type,
#Consumption.defaultValue: 'AP'
pm_approval : grac_approval_status
as select from YGAC_I_REQ_PROVISION_ITEM as provitem
association [1..1] to YGAC_I_ROLE as _Role on _Role.RoleId = provitem.ProvisionItemId
association [1..*] to YGAC_I_ROLE_RS as _Relation on _Relation.RoleId1 = provitem.ProvisionItemId
{
key ReqId,
key ReqIdItem,
Connector,
ProvisionItemId,
ActionType,
ValidFrom,
ValidTo,
_Role.RoleId,
_Role.RoleName,
_Role.RoleType,
_Role,
_Relation
}
where
ReqId = $parameters.pm_req_id
and ProvisionItemType = $parameters.pm_item_type
and ApprovalStatus = $parameters.pm_approval
Then I have consumed in ABAP:
SELECT
FROM ygac_i_request_role( pm_req_id = #lv_test,
pm_item_type = #lv_item_type,
pm_approval = #lv_approval
)
FIELDS reqid,
connector,
provisionitemid
INTO TABLE #DATA(lt_result).
How to get the list of _Relation according to selection above.
This is generally not possible like in ABAP SQL queries:
SELECT m~*, kt~*
FROM mara AS m
JOIN makt AS kt
...
This contradicts the whole idea of CDS associations, because they were created to join on-demand and to reduce redundant calls to database. Fetching all fields negates the whole idea of "lazy join".
However, there is another syntax in FROM clause which is enabled by path expressions that allows querying underlining associations both fully and by separate elements. Here is how
SELECT *
FROM ygac_i_request_role( pm_req_id = #lv_test )
\_Role AS role
INTO TABLE #DATA(lt_result).
This fetches all the fields of _Role association into internal table.
Note: remember, it is not possible to fetch all the published associations of current view simultaneously, only one path per query.
Possible workaround is to use JOIN
SELECT *
FROM ygac_i_request_role AS main
JOIN ygac_i_request_role
\_Role AS role
ON main~ProvisionItemId = role~RoleId
JOIN ygac_i_request_role
\_Relation AS relation
ON main~ProvisionItemId = relation~RoleId1
INTO TABLE #DATA(lt_table).
This creates deep-structured type with dedicated structure for every join association like this:
If you are not comfortable with such structure for you task, lt_table should be declared statically to put up all the fields in a flat way
TYPES BEGIN OF ty_table.
INCLUDE TYPE ygac_i_request_role.
INCLUDE TYPE ygac_i_role.
INCLUDE TYPE ygac_i_role_rs.
TYPES END OF ty_table.
I have an ASP.NET Web API app using Oracle's Entity Framework driver. I have an entity defined for a view as follows:
CREATE OR REPLACE FORCE VIEW "PHASE_TWO"."EDIPRODUCT" ("ID", "STK_NUM", "TITLE", "ISBN", "UPC", "ITEMNO", "LONGFORMAT", "ABRIDGED", "WEB_TITLES_ID", "OCLC", "GENRE", "RELYEAR", "ORIG_REL", "LANG", "ORIG_STKNUM", "PUBLISHER", "PEOPLELIST", "SALES_ORG", "NOT_AVAIL") AS
SELECT sap_product.id,
sap_product.stk_num,
sap_product.longdesc AS title,
sap_product.isbn,
sap_product.upc,
sap_product.itemno,
sap_product.longformat,
sap_product.abridged,
mwt_product.web_titles_id,
mwt_product.oclc,
mwt_product.genre,
mwt_product.RELYEAR,
sap_product.orig_rel,
sap_product.lang,
sap_product.orig_stknum,
UPPER (publisher.name) publisher,
(SELECT LISTAGG (p.FULLNAME, ', ') WITHIN GROUP (
ORDER BY pp.rank) AS People
FROM people p
JOIN product_people pp
ON p.id = pp.peopleid
WHERE pp.stk_num = sap_product.stk_num
GROUP BY pp.STK_NUM
) PeopleList,
sppg.PRICING_TYPE as sales_org,
sap_product.not_avail
FROM sap_product
JOIN mwt_product ON sap_product.stk_num = mwt_product.stk_num
JOIN publisher ON mwt_product.publisherid = publisher.id
JOIN SAP_PRODUCT_PRICING_GROUP sppg on sppg.STK_NUM = mwt_product.stk_num and sppg.MARKED_FOR_DELETION = 0
WHERE mwt_product.WEB_PRODUCTS_ID > 0;
This view works as expected in SQL Developer. My getEDIPRODUCT function (yes, it's VB.NET) in my controller is as follows:
' GET: odata/EDIPRODUCTs
<EnableQuery>
Function GetEDIPRODUCT() As IQueryable(Of EDIPRODUCT)
Dim results As IQueryable
results = db.EDIPRODUCT
For Each _product In results
Console.Write(_product)
Next
Return results
End Function
I just added the for loop in order to inspect the results. What I see when I inspect the results is the same product record is returned for each row. The value for the ID is duplicate and the only other field that should have variant values (sppg.PRICING_TYPE as sales_org) also just repeats.
I have other views where this does not occur. The correct number of records are always returned, but the first record retrieved is always just repeated in each row of the result set. Any idea what could be going on here?
I never actually resolved this issue and am still interested in why this fails, but I rewrote the portion of the app that uses this view to use OData's $expand to retrieve the related data.
I'm building a system with messages that can be assigned to (one or more) users.
Table: Messages
id
text
Table: Assignments
id
remark
status
Table: Assignment_User
id
assignment_id
user_id
Table: Users
id
name
Now I want to retrieve all assigned messages for a specific user
$qb->select('DISTINCT m')
->from('MessageBundle:Assignment', 'a')
->join('MessageBundle:Message', 'm')
->join('MessageBundle:AssignmentUser', 'au')
->where('a.message = m')
->andWhere('au.assignment = a')
->andWhere('a.status = (:assigned)')
->setParameter('assigned', 'assigned')
->orderBy("mr.createdAt", "desc");
As soon as I add that second JOIN it throws an error...
Error: Expected Literal, got 'JOIN'
What would be the correct way to get all assigned messages for user X?
Doctrine should already understand how your tables relate through your entity mappings (if not, you might need to set those up first). Rather than trying to join a whole table and then specifying what the table is joined on (SQL-style), just join, for example, au.assignment as a.
At that point, you can also specify any additional conditions on your join, such as you'd want on a.status.
You might prefer to reorder the joins below depending on what associations you have set up in which directions (I don't know whether your Message has an assignments property, for example).
$qb->select('DISTINCT m')
->from('MessageBundle:AssignmentUser', 'au')
->innerJoin('au.assignment', 'a', 'WITH', 'a.status = (:assigned)')
->innerJoin('au.user', 'u')
->innerJoin('a.message', 'm')
->where('u.id = (:user_id)')
->setParameter('assigned', 'assigned')
->setParameter('user_id', $yourSpecificUserId)
->orderBy("m.createdAt", "desc");
I have a class that has a List that I wish to relate to through a join table to allow 1-M and M-1 relations in the same time. In other words, I'd like to reuse the elements in the list.
In case that doesn't make sense or is inapplicable in a way please advice as I'm still trying to design that part of the model.
So the list is mapped this way:
#Persistent(table = "ixl_csv_metric_rel", defaultFetchGroup = "true")
#Join(column = "ixl_csv_fk")
#Order(column = "order")
#Element(dependent = "true", column = "ixl_metric_fk")
private List<IxlMetric> metrics;
The thing is that the join table is created with a compound primary key composed of the ixl_csv_fk and order columns which isn't what I need. The primary key would better be composed of the ixl_metric_fk column instead of the order column which make a lot more sense to me.
I can disable generating the primary key and set it manually later on but I was wondering if there was a better way to do it ?
#Join(column = "ixl_csv_fk", extensions = { #Extension(vendorName = "datanucleus", key = "primary-key", value = "false") })
No other way. Disable it and manually override it yourself. JDO provides the only sensible way of doing it to match the class definitions and a List field.
Actually I spend whole day on the EntityFramework for foreign key.
assume we have two table.
Process(app_id,process_id)
LookupProcessId(process_id, process_description)
you can understand two tables with names, first table ,use process_id to indicate every application, and description is in the seoncd table.
Actually i try many times and figure out how to do inquery: it was like
Dim result = (from x in db.Processes where x.LookupProcess is (from m in db.LookupProcessIds where descr = "example" select m).FirstOrDefault() select x).FirstOrDefault()
First I want to ask is there easier way to do it.
Second i want to ask question is about insert
p As New AmpApplication.CUEngData.Process
p.app_id=100
p.LookupProcess = (from m in db.LookupProcessIds where descr = "example" select m).FirstOrDefault()
db.AddToProcesses(p)
db.SaveChanges()
from appearance it looks fine, but it give me error says
Entities in 'AmpCUEngEntities.Processes' participate in the 'FK_Process_LookupProcess' relationship. 0 related 'LookupProcess' were found. 1 'LookupProcess' is expected.
can i ask is that insert wrong? and is that my query correct?
For your first question:
Dim result = (from x in db.Processes
where x.LookupProcess.descr = "example"
select x).FirstOrDefault()
Actually, you missed some concepts from DataEntityModel, and its Framework. To manipulate data, you have to call object from contextual point of view. Those allow you to specify to the ObjectStateManager the state of an DataObject. In your case, if you have depending data from FK, you will have to add/update any linked data from leaf to root.
This example demonstrate simple (no dependances) data manipulation. A select if existing and an insert or update.
If you want more info about ObjectStateManager manipulation go to http://msdn.microsoft.com/en-us/library/bb156104.aspx
Dim context As New Processing_context 'deseign your context (this one is linked to a DB)
Dim pro = (From r In context.PROCESS
Where r.LOOKUPPROCESS.descr = LookupProcess.descr
Select r).FirstOrDefault()
If pro Is Nothing Then 'add a new one
pro = New context.PROCESS With {.AP_ID = "id", .PROCESS_ID = "p_id"}
context.PROCESS.Attach(pro)
context.ObjectStateManager.ChangeObjectState(pro, System.Data.EntityState.Added)
Else
'update data attibutes
pro.AP_ID = "id"
pro.PROCESS_ID = "p_id"
context.ObjectStateManager.ChangeObjectState(pro, System.Data.EntityState.Modified)
'context.PROCESS.Attach(pro)
End If
context.SaveChanges()
I hope this will help. Have a nice day!
For your first question, to expand on what #jeroenh suggested:
Dim result = (from x in db.Processes.Include("LookupProcess")
where x.LookupProcess.descr = "example"
select x).FirstOrDefault()
The addition of the Include statement will hydrate the LookupProcess entities so that you can query them. Without the Include, x.LookupProcess will be null which would likely explain why you got the error you did.
If using the literal string as an argument to Include is not ideal, see Returning from a DbSet 3 tables without the error "cannot be inferred from the query" for an example of doing this using nested entities.
For your second question, this line
p.LookupProcess = (from m in db.LookupProcessIds
where descr = "example" select m).FirstOrDefault()
Could cause you problems later on because if there is no LookupProcessId with a process_description of "example", you are going to get null. From MSDN:
The default value for reference and nullable types is null.
Because of this, if p.LookupProcess is null when you insert the entity, you will get the exception:
Entities in 'AmpCUEngEntities.Processes' participate in the 'FK_Process_LookupProcess' relationship. 0 related 'LookupProcess' were found. 1 'LookupProcess' is expected.
To avoid this kind of problem, you will need to check that p.LookupProcess is not null before it goes in the database.
If Not p.LookupProcess Is Nothing Then
db.AddToProcesses(p)
db.SaveChanges()
End If