I am trying to write a query that gets a row when the id is equal to 1 (at the moment).
NSPredicate *predicate = [NSPredicate predicateWithFormat:[apt[#"id"] isEqualToNumber:1]];
So where id (from another database) is equal to 1. Now this is complaining all sorts of things but its saying it needs to be a BOOL. Is NSPredicate needing a BOOL?
Not sure I understand, or is there another way I can query? Can I use T-SQL in Mobile Services SDK Azure for iOS?
The predicate with format expects a string, you are sending in a bool. [apt[#"id"] isEqualToNumber:1] returns a bool.
Use the predicate in this manner (I have little experience with formatting predicates, so this will likely not actually work for you to copy and paste in).
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"id == 1"];
This will work if your objects in the array you are filtering have a property called id.
Something I understand a littler better is predicates with blocks. This could work for you too (I'm not entirely sure of your data structure, so you are gong to have to modify to suit your needs.
NSPredicate *predicate = [NSPredicate predicateWithBlock:^BOOL(id object, NSDictionary *bindings) {
return [object[#"id"] isEqualToNumber:1]; // Return YES for each object you want in filteredArray.
}]
Related
I'm trying to build a predicate that compares two members of a too-many relationship.
The code below more clearly shows my intention, but doesn't seem to work (assume objects is the too-many relationship and has members, member1 and member2):
[NSPredicate predicateWithFormat:
#"(ANY objects.member1 ==[cd] objects.member2)"];
I appreciate any help in determining a properly structured predicate for this type of comparison.
Assuming that you want to fetch the objects which are related to at least one object with
"member1 == member2", you have to use a SUBQUERY:
[NSPredicate predicateWithFormat:#"SUBQUERY(objects, $o, $o.member1 == $o.member2).#count > 0"]
You can find a similar example in the NSExpression Class Reference.
I have 3 core data entities.
MenuItems, Items, ItemLangs.
All entities has iItemId attribute. The user need to search using sItemName which can be found in the ItemLangs.
The UITableView contains array of MenuItems.
I have tried filteredArrayUsingPredicate but my predicate is not right. Do I need to loop through the array of MenuItems first before I can filter the array?
Here is my predicate:
NSPredicate *resultPredicate = [NSPredicate
predicateWithFormat:#"sItemName LIKE %#", searchText];
May I know how can I use this to filter the array of MenuItems that I have?
Thank you!
What you need is a predicate like this:
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"sItemName CONTAINS[cd] %#", searchText];
[cd] stands for case insensitiveness.
Alternately, if you like "LIKE", refer to this answer.
UPDATE:
You should also look at the data item you want to fetch - sItemName in your case. Through debugger, inspect what object does your data source array return? I am referring to the array you want to apply the above predicate to. Maybe there is some keypath hierarchy involved in getting through towards sItemName, in which case you need to use dot notation, such as Items.ItemLangs.sItemName.
Refer following links, it may help you:
1) How to implement SearchBar and search display controller in tableview in xib
2) first attempt at synamic filtering a search array
3) http://www.appcoda.com/search-bar-tutorial-ios7/
4) http://www.raywenderlich.com/16873/how-to-add-search-into-a-table-view
Im trying to implement something that I'm sure have been implemented a million times before, a search in the core data database, displayed in a table using a fetchRequestController and the searchController.
My problem is writing the NSPredicate for the NSFetchRequest. According to the NSPredicate guide by Apple, not everything you can do in Sqlite is possible with core data.
I have been trying to find a solution for some time, but maybe one of you can use his experience to help me.
CoreData DB description:
Shops has a MANY TO MANY relationship with DiscountProgam.
My use case is as follows: I need to filter out Shops who's name/address/zip/city contains the search string. that's the easy part.
The hard part is creating the section of the database I want to filter from, because I have an array of "active" discountPrograms UID's, and I only want shops that have one of the active discount programs in their "discountPrograms" set. So in pseudo code that would be:
FROM Shops who have at least one discountProgram who's uid IN activeDiscountProgramsArray WHERE name/address/zip/city CONTAINS searchString
Is this possible? am I over reaching the limits of predicates?
If so, how could I do it differently?
Yes, NSPredicate can analyse both the direct attributes of the target entity of a fetch and the attributes of its relationships. Try:
NSArray *validUIDs = ...;
NSString *searchTerm = ...;
[NSPredicate predicateWithFormat:#"(name CONTAINS[cd] %# OR zip CONTAINS[cd] %#) AND (SUBQUERY(discountProgram, $d, $d.UID IN %#).#count > 0)", searchTerm, searchTerm, validUIDs];
I've had a hard time putting together the correct search terms to find this answer, so I thought I'd try to ask it. I'm still getting to know Core Data.
I have a Player entity and a School entity. The player has a to-many relationship with schools.
I want all Player objects where the School name attribute can be one of several values (ie, I want all players that have gone to either Stanford, Yale, or Duke). I imagine that I need to use the 'IN' clause, something like
[NSPredicate predicateWithFormat:#"schools.name IN ("%#", "%#", "%#"), #"Stanford", #"Yale", #"Duke"];
Don't quote inside the predicate format string
[NSPredicate predicateWithFormat:#"ANY schools.name IN (%#, %#, %#)", #"Stanford", #"Yale", #"Duke"];
but this is a useless bit of code. Given an NSArray of names then I believe you can do this:
[NSPredicate predicateWithFormat:#"ANY schools.name IN %#", arrayOfNames];
Finally got it.
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"ANY schools IN %#", schoolObjectArray];
The relationship from Player to Schools is schools, and the schoolObjectArray contains the School NSManagedObjects that I want.
maybe?
[NSPredicate predicateWithFormat:#"schools.name IN (\"%#\", \"%#\", \"%#\")", #"Stanford", #"Yale", #"Duke"];
I am trying to write a predicate similar to
[NSPredicate predicateWithFormat:#"ANY manyNames in %#", allNames];
but instead of 'in' I need 'like'
[NSPredicate predicateWithFormat:#"ANY manyNames like %#", allNames];
This causes an error.
So I want to get results with some objects of manyNames, which are similiar to at least one of allNames.
I solved my problem by joining the strings and making one string of them, then looking for that.