Thank you Aaron,
I've wondered for a long time on the best way to achieve that!
I'm preparing a pull request to add some methods in ERXQ and ERXKey to help
using that...
In ERXQ (based on your code):
/**
* Return an identity qualifier to use with ERXExistsQualifier for example
public static EOQualifier is(ERXGenericRecord value) {
/**
* Return a OR qualifier of identity qualifier using each value from the param
array
public static EOQualifier isIn(NSArray<? extends ERXGenericRecord> valueArray) {
in ERXKey:
/**
* Uses ERXExistsQualifier with an array of identity qualifiers to build a
qualifier that
* returns true if at least one the objects specified is found in the to many
relationship
* represented by this key.
public ERXExistsQualifier containsAnyOfTheseObjects(NSArray<? extends
ERXGenericRecord> valueArray) {
I also added shortcuts to create an ERXExistsQualifier that uses IN:
public ERXExistsQualifier containsAnyObjectSatisfyingUsingIn(EOQualifier
qualifier) {
public ERXNotQualifier doesNotContainsAnyObjectSatisfyingUsingIn(EOQualifier
qualifier) {
I'm open to comments on the methods names before sending the pull request.
Samuel
> Le 12 mai 2016 à 23:28, Aaron Rosenzweig <[email protected]> a écrit :
>
> Hi Paul and everyone,
>
> What you did is ok - not bad but since you are asking for more here you go.
>
> It is probably a bad idea to model the back relationship from “Role -> Users”
> as one role could be used by thousands of users. You don’t want to fault all
> those people in when you “addToBothSidesOfRelationshipWithKey().” That said
> you *could* model it and be careful to not add to both sides and be careful
> never to trip that fault. You could also model it as a “non class” invisible
> property. If you had this relationship you could do the following.
>
> EOQualifier noticeQualifierForUser =
> Notice.ROLES.dot(Role.USERS).containsAnyObjectSatisfying(loggedInUser.identityQualifier())
>
> You can use that one qualifier to fetch all the Notices for your user.
>
> The “identityQualifier()” could be defined in your EO like so:
>
> public EOQualifier identityQualifier() {
> final EOEntity entity = entity();
> final NSDictionary<String, Object> primaryKeyDictionary =
> primaryKeyDictionary(false /* inTransaction */);
> final EOQualifier thatAreThis =
> entity.qualifierForPrimaryKey(primaryKeyDictionary);
> return thatAreThis;
> }
>
> Note: “containsAnyObjectSatisfying()” is a thin wrapper of
> “ERXExistsQualifier.” If you prefer, you could create that exists qualifier
> directly and specify if you want an “in” or exists syntax to be generated.
>
> AARON ROSENZWEIG / Chat 'n Bike <http://www.chatnbike.com/>
> e: [email protected] <mailto:[email protected]> t: (301) 956-2319
>
>
> On May 10, 2016, at 6:22 PM, Paul Hoadley <[email protected]
> <mailto:[email protected]>> wrote:
>
>> Hello,
>>
>> I have two entities, User and Notice, each of which has a to-many
>> relationship to Role called roles. The business rule here works as follows.
>> Say Notice.roles contains two Roles, R1 and R2. If User.roles contains
>> either R1 or R2, then the Notice is applicable to that User—that is,
>> Notice.roles says that for each Role, the Notice applies to any User that
>> has that Role.
>>
>> I have a static method on Notice to return an NSArray<Notice> applicable to
>> some supplied User. (There are other matching criteria, but this is the part
>> I want to try and simplify.) At the moment, I’m doing this:
>>
>> NSMutableArray<EOQualifier> roleQuals = new
>> NSMutableArray<EOQualifier>();
>> for (Role r : user.roles()) {
>> roleQuals.add(Notice.ROLES.containsObject(r));
>> }
>> EOQualifier roleQual = ERXQ.or(roleQuals);
>>
>> While this works, it seems awkward. Is there a way to create this qualifier
>> (which is essentially looking for any match between User.roles and
>> Notice.roles) in one step?
>>
>>
>> --
>> Paul Hoadley
>> http://logicsquad.net/ <http://logicsquad.net/>
>>
>>
>>
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