Hi,
I'm struggling a bit here trying to figure out a way to generate dynamic
views for map/reduce.
I have an entity called TFRecord that contains record details. Each
instance of TFRecordDetails can have a different schema depending on the
TFForm and set of TFFields defined.
I've created my view like this on my TFForm model entity:
NSString *viewName = [NSString stringWithFormat:@"records-%@", self.document
.documentID];
CBLView *recordsView = [self.database viewNamed:viewName];
So as you can see the name of the records view is generated from the
document ID of the TFForm entity.
These records need to be sorted by multiple levels of sorting criteria.
I've got these keys that I'd like to use to reference the values from the
TFRecord document for sorting purposes. They can be first sorted by a
grouping field, then a first sort field, second sort field, and third sort
field as defined on the TFForm class.
NSString *groupFieldKey = [self.groupField valueKeyName];
NSString *sortField1Key = [self.sortField1 valueKeyName];
NSString *sortField2Key = [self.sortField2 valueKeyName];
NSString *sortField3Key = [self.sortField3 valueKeyName];
So somehow I need to be able to generate a map/reduce function that will
extract the values from the TFRecord entity based on the keys from the
above vars. But according to the documentation, the map/reduce functions
must be pure and not reference any external state information, only
referencing values from the document JSON itself.
Does that means it's not possible to generate a view from a dynamically
generated set of keys?
This is what one record looks like in my model:
{
"alertCount": "0",
"dateCreated": "2014-09-29 05:44:32 +0000",
"dateModified": "2014-09-29 05:44:51 +0000",
"formId": "form-11770309-9278-445D-A0E5-FF9B05D2552E",
"hasAlarm": "0",
"isFavourite": "0",
"linkFromField": "field-008C209D-A199-423C-8027-3813AA848F84",
"linkFromRecord": "rec-1E774FB1-A419-48AC-ACA5-5A8A7EC0D5A5",
"primaryKey": "3E3E0DA3-3809-4A13-8B81-353404C970FB",
"sortOrder": "0",
"type": "TFFormEntry",
"values": {
"field-2AE29531-6B5F-4D45-9625-C9D43520778A-note": "Deployment of
updated Tap Forms version under way.",
"field-608BE174-A17F-46F7-88A7-D02F3E7D2B01-date_time": "2014-09-29
05:44:40 +0000",
"field-C6572946-36E0-4ED9-BF02-A01F4D787FE6-text": "Deploy Tap Forms"
}
}
One or more of the groupFieldKey, sortField1Key, sortField2Key, or
sortField3Key may be in the set of values in the document. "values" is a
dictionary on my TFRecord model object where I'm storing all the values for
a record, keyed by the field's ID.
So basically I don't know what to put into the map block to achieve what I
need. I also need to be able to query these objects in a number of
different ways. But I'll get to that once I can figure out how to get my
records sorted. The user may even have a different set of fields displayed
in the list than what they are sorting on.
I tried building a function that was referencing those keys above, but that
obviously doesn't work.
Any ideas?
I just don't know what to emit here:
if (!recordsView.mapBlock) {
[recordsView setMapBlock: MAPBLOCK({
if ([doc[@"type"] isEqualToString:@"TFRecord"]) {
// what do I put here to be able to extract out the values
// for the dynamically generated groupFieldKey, sortField1Key,
// sortField2Key, and sortField3Key?
NSDictionary *values = doc[@"values"];
// need to get the value for the dynamic keys from the
// values dictionary then emit that value.
emit(@[doc[groupField1Key], doc[sortField1Key], doc[sortField2Key
], doc[sortField3Key]], doc);
}
}) reduceBlock:^id(NSArray *keys, NSArray *values, BOOL rereduce) {
return @(values.count);
} version: @"1"];
}
The above is obviously not pure because it references the local "Key"
variables within the map function.
So I'm stuck.
Thanks,
Brendan
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