List item
So I'm trying to set up a request with multiple conditions in Swift. The SQL equivalent to:
select BOARDID
from BOARD
where BOARDID not like "someBoard"
and BOARDID not like "anotherBoard"
..
I have an array of strings and I'm trying to iterate over each to create a subPredicate, add it to a compoundPredicate, then create a fetch request using that compoundPredicate:
let openBoards = ["someBoard", "anotherBoard", "etc"],
request = NSFetchRequest(entityName: "Board")
var openBoardsSubPredicates: Array = [],
error: NSError? = nil
for board in openBoards {
var subPredicate = NSPredicate(format: "boardID not like '\(board)'")
openBoardsSubPredicates += subPredicate
}
request.predicate = NSCompoundPredicate.andPredicateWithSubpredicates(openBoardsSubPredicates)
However, it fails at the var subPredicate line..
Thanks!
The error tells you what the problem is. The format you are providing is not a valid format. Specifically, there is no "not like" comparison. You have to do the "not" outside:
NSPredicate(format: "not (boardID like %#)", board)
As #MartinR mentioned below, you can have NSPredicate automatically escape special characters so they don't interfere with the predicate by having it insert the variable instead of using string interpolation.
Related
I have been searching for hours and no solution in sight... I am filtering an array of custom objects using the text typed into a UISearchBar to change the data in the tableview below.
After a bit of debugging, ive pin pointed the source of my troubles:
func searchBar(searchBar: UISearchBar, textDidChange searchText: String) {
var temp = "c"
FilterResults = SearchResults.filter {
return $0.Username.rangeOfString(temp) != nil
}
}
here is my trouble: If I used a temp that is explicitely defined as above , where temp = "c", it happily matches all the user names that have a c in it! The issue arises when instead of using temp, I used the variable searchText, in that cases it never EVER matches with anything! I checked and searchText is not null, in fact I printed out searchText in tests and it printed out a normal string (Based on what is typed in the search bar), but for some crazy reason, if I use the searchText variable inside the .rangeOfString method, it always returns false! Why is that? Ive also used searchBar.text and it gave me the same troubles... I am completely lost and frustrated. Any help would be much appreciated!
Try this if it works.
var searchList = [String]()
let searchPredicate = NSPredicate(format: "SELF CONTAINS[c] %#", searchText!)
let array = (searchList as NSArray).filteredArrayUsingPredicate(searchPredicate) as! [String]
Turns out it was because I didn't realize that the rangeOfString search is case sensitive!
I need to return a list of objects along with a count of its related objects. It doesn't seem to be possible to do this in a single dictionary fetch request as I am unable to group the fetch results by objectID.
let objectIDExpression = NSExpressionDescription()
objectIDExpression.name = "objectID"
objectIDExpression.expression = NSExpression.expressionForEvaluatedObject()
objectIDExpression.expressionResultType = NSAttributeType.ObjectIDAttributeType
let countExpression = NSExpressionDescription()
countExpression.name = "count"
countExpression.expression = NSExpression(forFunction: "count:", arguments: [NSExpression(forKeyPath: "entries")])
countExpression.expressionResultType = .Integer32AttributeType
let fetchRequest = NSFetchRequest(entityName: "Tag")
fetchRequest.resultType = .DictionaryResultType
fetchRequest.propertiesToFetch = [objectIDExpression, countExpression]
fetchRequest.propertiesToGroupBy = [objectIDExpression]
var error: NSError?
if let results = self.context.executeFetchRequest(fetchRequest, error: &error) {
println(results)
}
When this request executes it errors with:
'Invalid keypath expression ((<NSExpressionDescription: 0x7f843bf2d470>), name objectID, isOptional 1, isTransient 0, entity (null), renamingIdentifier objectID, validation predicates (
), warnings (
), versionHashModifier (null)
userInfo {
}) passed to setPropertiesToFetch:'
I also tested just passing the "objectID" expression name, but that also fails.
Is there therefore no way to group by object ID?
You can get the required count without using propertiesToGroupBy. CoreData seems to infer the correct scope for the count and uses a sub-SELECT instead (strangely, only if the fetch includes an attribute as well as the objectID and count, see below). For example, I have Tag many-many with Items:
First attempt
I can fetch tagName and the count of items as follows:
NSFetchRequest *fetch = [NSFetchRequest fetchRequestWithEntityName:#"Tag"];
NSExpressionDescription *countED = [NSExpressionDescription new];
countED.expression = [NSExpression expressionWithFormat:#"count:(items)"];
countED.name = #"countOfItems";
countED.expressionResultType = NSInteger64AttributeType;
fetch.resultType = NSDictionaryResultType;
fetch.propertiesToFetch = #[#"tagName", countED];
NSArray *results = [self.context executeFetchRequest:fetch error:nil];
NSLog(#"results is %#", results);
which generates the following SQL:
SELECT t0.ZTAGNAME, (SELECT COUNT(t1.Z_3ITEMS) FROM Z_3TAGS t1 WHERE (t0.Z_PK = t1.Z_8TAGS) ) FROM ZTAG t0
Second attempt
Sadly, it seems CoreData gets confused if I try to select the objectID instead of the tagName:
NSExpressionDescription *selfED = [NSExpressionDescription new];
selfED.expression = [NSExpression expressionForEvaluatedObject];
selfED.name = #"self";
selfED.expressionResultType = NSObjectIDAttributeType;
fetch.resultType = NSDictionaryResultType;
fetch.propertiesToFetch = #[selfED, countED];
generates this SQL:
SELECT t0.Z_ENT, t0.Z_PK, COUNT( t1.Z_3ITEMS) FROM ZTAG t0 LEFT OUTER JOIN Z_3TAGS t1 ON t0.Z_PK = t1.Z_8TAGS
which counts all the rows from the outer join (and suggests that you need to group by the objectID, though we know that won't work).
Final attempt
However, include tagName and objectID, and all is well again:
fetch.propertiesToFetch = #[selfED, #"tagName", countED];
gives:
SELECT t0.Z_ENT, t0.Z_PK, t0.ZTAGNAME, (SELECT COUNT(t1.Z_3ITEMS) FROM Z_3TAGS t1 WHERE (t0.Z_PK = t1.Z_8TAGS) ) FROM ZTAG t0
which seems to do the trick. (Sorry for reverting to Objective-C, and for using different entity/attribute names, but I'm sure you get the picture).
Aside
One other curiosity I discovered is that the second attempt above can also be made to work by counting an attribute of the relationship, rather than the relationship itself:
countED.expression = [NSExpression expressionWithFormat:#"count:(items.itemName)"];
fetch.propertiesToFetch = #[selfED, countED];
gives:
SELECT t0.Z_ENT, t0.Z_PK, (SELECT COUNT(t2.ZITEMNAME) FROM Z_3TAGS t1 JOIN ZITEMS t2 ON t1.Z_3ITEMS = t2.Z_PK WHERE (t0.Z_PK = t1.Z_8TAGS) ) FROM ZTAG t0
which will (I think) give the correct counts provided itemName is not nil.
I played with this for a bit, sure there had to be some way to tell core-data to group by the primary key.
I couldn't figure it out, though I believe it to be possible.
The best I could do was add another unique attribute "uuid" (which I use for all of my entities anyway, for various reasons). You can do this easily enough with NSUUID, or you can take the permanent object ID URI representation and turn it into a string.
Anyway, I think this gives you what you want, but does so by requiring a separate unique attribute.
fetchRequest.propertiesToGroupBy = #[#"uuid"];
I tried a bunch of alternatives as the group-by property but expressionForEvaluatedObject always barfs, and other attempts fell flat.
I'm sure you know this already. Just in case, though it's at least a workaround, even if you don't use it for anything else, until someone comes around who has actually done this before.
FWIW, here is the SQL...
CoreData: sql: SELECT t0.Z_ENT, t0.Z_PK, COUNT( t1.Z_1ENTRIES), t0.ZUUID
FROM ZTAG t0 LEFT OUTER JOIN Z_1TAGS t1 ON t0.Z_PK = t1.Z_2TAGS
GROUP BY t0.ZUUID
Surely, there has to be a way to tell it to substitute t0.Z_PK in the group-by clause. I would image that should be an easy special case for expressionForEvaluatedObject or "objectID" or "self" or "self.objectID"
Good luck, and please report back if you solve it. I'd be very interested.
It is perhaps easier to use a NSFetchedResultsController. You can set the sectionNameKeyPath to group and use the resulting NSIndexPaths to construct your dictionary.
That being said, I do not think that it makes any sense to group by objectID because every object ID is by definition unique. So there will be one instance in each group. This is likely why setting propertiesToGroupBy fails.
So, short answer: no.
E.g.
let fetchRequest = NSFetchRequest(entityName: "Tag")
var output = [(NSManagedObjectID, Int)]()
do {
let results = try context.executeFetchRequest(request) as! [Tag]
for tag in results {
output.append((tag.objectID, tag.entries.count))
}
} catch {}
// output contains tuples with objectID and count
If entriesis optional, use tag.entries?.count ?? 0.
I have one CoreData record that contains all of the app's settings. When I read that single record (using MagicalRecord), I get an array back. My question is: can I get addressabiltiy to the individual fields in the record without using "[0]" (field index), but rather using [#"shopOpens"]?
I was thinking something like this, but I don't think it's right:
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"aMostRecentFlag == 1"]; // find old records
preferenceData = [PreferenceData MR_findAllWithPredicate:predicate inContext:defaultContext]; // source
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
NSMutableDictionary *preferencesDict = [[userDefaults dictionaryForKey:#"preferencesDictionary"] mutableCopy]; // target
// start filling the userDefaults from the last Preferences record
/*
Printing description of preferencesDict: {
apptInterval = 15;
colorScheme = Saori;
servicesType = 1;
shopCloses = 2000;
shopOpens = 900;
showServices = 0;
syncToiCloud = 0;
timeFormat = 12;
}
*/
[preferencesDict setObject: preferenceData.colorScheme forKey:#"shopOpens"];
UPDATE
This is how I finally figured it out, for those who have a similar question:
NSPredicate *filter = [NSPredicate predicateWithFormat:#"aMostRecentFlag == 0"]; // find old records
NSFetchRequest *freqest = [PreferenceData MR_requestAllWithPredicate: filter];
[freqest setResultType: NSDictionaryResultType];
NSDictionary *perferenceData = [PreferenceData MR_executeFetchRequest:freqest];
Disclaimer: I've never used magical record, so the very first part is just an educated guess.
I imagine that preferenceData is an instance of NSArray firstly because the method name uses findAll which indicates that it will return multiple instances. Secondly, a normal core data fetch returns an array, and there is no obvious reason for that find method to return anything different. Thirdly, you referenced using an index operation in your question.
So, preferenceData is most likely an array of all objects in the store that match the specified predicate. You indicated that there is only one such object, which means you can just grab the first one.
PreferenceData *preferenceData = [[PreferenceData
MR_findAllWithPredicate:predicate inContext:defaultContext] firstObject];
Now, unless it is nil, you have the object from the core data store.
You should be able to reference it in any way you like to access its attributes.
Note, however, that you can fetch objects from core data as dictionary using NSDictionaryResultType, which may be a better alternative for you.
Also, you can send dictionaryWithValuesForKeys: to a managed object to get a dictionary of specific attributes.
I have a list AllIDs:
List<IAddress> AllIDs = new List<IAddress>();
I want to do substring operation on a member field AddressId based on a character "_".
I am using below LINQ query but getting compilation error:
AllIDs= AllIDs.Where(s => s.AddressId.Length >= s.AddressId.IndexOf("_"))
.Select(s => s.AddressId.Substring(s.AddressId.IndexOf("_")))
.ToList();
Error:
Cannot implicitly convert type 'System.Collections.Generic.List<string>' to 'System.Collections.Generic.List<MyCompany.Common.Users.IAddress>'
AllIDs is a list of IAddress but you are selecting a string. The compiler is complaining it cannot convert a List<string> to a List<IAddress>. Did you mean the following instead?
var substrings = AllIDs.Where(...).Select(...).ToList();
If you want to put them back into Address objects (assuming you have an Address class in addition to your IAddress interface), you can do something like this (assuming the constructor for Address is in place):
AllIDs = AllIDs.Where(...).Select(new Address(s.AddressID.Substring(s.AddressID.IndexOf("_")))).ToList();
You should also look at using query syntax for LINQ instead of method syntax, it can clean up and improve the readability of a lot of queries like this. Your original (unmodified) query is roughly equivalent to this:
var substrings = from a in AllIDs
let id = a.AddressId
let idx = id.IndexOf("_")
where id.Length >= idx
select id.Substring(idx);
Though this is really just a style thing, and this compiles to the same thing as the original. One slight difference is that you only have to call String.IndexOf() one per entry, instead of twice per entry. let is your friend.
Maybe this?
var boundable =
from s id in AllIDs
where s.AddressId.Length >= s.AddressId.IndexOf("_")
select new { AddressId = s.AddressId.Substring(s.AddressId.IndexOf("_")) };
boundable = boundable.ToList();
I have a lookup field in sharepoint which just references another list. I wonder how do I programatically enumerate all possible values for this field?
For example, my lookup field "Actual City" refers list "Cities" and column "Title", I have 3 cities there. In code I would like to get list of all possible values for field "Actual City", smth like (metacode, sorry):
SPFieldLookup f = myList["Actual City"];
Collection availableValues = f.GetAllPossibleValues();
//this should return collection with all cities a user might select for the field
I wrote some code to handle this for my project just the other day. Perhaps it will help.
public static List<SPFieldLookupValue> GetLookupFieldValues(SPList list, string fieldName)
{
var results = new List<SPFieldLookupValue>();
var field = list.Fields.GetField(fieldName);
if (field.Type != SPFieldType.Lookup) throw new SPException(String.Format("The field {0} is not a lookup field.", fieldName));
var lookupField = field as SPFieldLookup;
var lookupList = list.ParentWeb.Lists[Guid.Parse(lookupField.LookupList)];
var query = new SPQuery();
query.Query = String.Format("<OrderBy><FieldRef Name='{0}'/></OrderBy>", lookupField.LookupField);
foreach (SPListItem item in lookupList.GetItems(query))
{
results.Add(new SPFieldLookupValue(item.ID, item[lookupField.LookupField].ToString()));
}
return results;
}
Then to use it, your code would look something like this:
var list = SPContext.Current.Web.Lists["My List"];
var results = GetLookupFieldValues(list, "Actual City");
foreach (SPFieldLookupValue result in results)
{
var value = result.LookupValue;
var id = result.LookupId;
}
I think there is no explicit method returning what you want. But the SPFieldLookup class stores all the info you need to request this information manually: LookupField and LookupList
So you could retrieve the information by getting it form the list you lookup field uses. To make it reusable you could implement it as a Extension Method. So the next time you could really call f.GetAllPossibleValues();.
As I understand you want to query all values that are in use?
If so, you would have to query items where Actual City is not null, query would look something like:
<Where><IsNotNull><FieldRef Name='Actual City'/></IsNotNull></Where>
Then, for each queried item you would
List<SPFieldLookupValue> result = new List<SPFieldLookupValue>(returnedItemCount * 5);
foreach (SPListItem item in queriedItems) {
object lookup = item["Actual City"];
SPFieldLookupValueCollection lookupValues = new SPFIeldLookupValueCollection(
(lookup != null) ? lookup.ToString() : ""
);
foreach (SPFieldLookupValue lookupValue in lookupValues) {
if (!result.Contains(lookupValue)) {
result.Add(lookupValue);
}
}
}
Or you could use HashTable where LookupId would be string and LookupValue would be int id and then check if HashTable.ContainsKey(lookupId)... must be faster to find an integer in hashtable rather than string in list, but the resource intensive part is to probably query all items where that field contains some value and then loop...
If you want to enumerate all possible values, that means you basically want to get all the Title field values from all the items in the Cities list. I don't think there is a method like GetAllPossibleValues() in SharePoint, but you can either just list all the items in Cities and get their titles, if there's just a few, or use a CAML query if there's plenty.