Each of my IndexedDB objects have the following format:
object:
{
objectName: "someName"
objectTest: "someTest"
objectAge: "someAge"
}
Then I have the following indexes already set:
storeObject.createIndex( "by_objectName", "objectName", { unique: false } );
storeObject.createIndex( "by_objectTest", "objectTest", { unique: false } );
storeObject.createIndex( "by_objectAge", "objectAge", { unique: false } );
So first I wanted to loop through all my objects by objectName (this is working):
var openedIndex = storeObject.index("by_objectName");
var numItemsInIndex = openedIndex.count();
if (openedIndex) {
var curCursor = openedIndex.openCursor();
curCursor.onsuccess = function(evt) {
var cursor = evt.target.result;
if (cursor) {
//do something
cursor.continue();
}
}
}
So the above code is taking all the objects and they are sorted by objectName.
How can I take all the objects that have objectTest: "certainValue" and the sorting by objectName to remain the same as in the above example. I need to filter the list of result before the line if (openedIndex) { because I need to use the numItemsInIndex later in the loop.
So in other words, if this was relational database, how to implement:
SELECT * FROM objects WHERE objectTest = "certainValue" SORT BY objectName
You can create an index on two properties at once by defining the keyPath parameter to createIndex as an array. Use the property you wish to sort by as the first item in the array. For example, see my other posts, like this one: In IndexedDB, is there a way to make a sorted compound query?
Related
I apologize for the title, I don't exactly know how to word it. But essentially, this is a graph-type query but I know RavenDB's graph functionality will be going away so this probably needs to be solved with Javascript.
Here is the scenario:
I have a bunch of documents of different types, call them A, B, C, D. Each of these particular types of documents have some common properties. The one that I'm interested in right now is "Owner". The owner field is an ID which points to one of two other document types; it can be a Group or a User.
The Group document has a 'Members' field which contains an ID which either points to a User or another Group. Something like this
It's worth noting that the documents in play have custom IDs that begin with their entity type. For example Users and Groups begin with user: and group: respectively. Example IDs look like this: user:john#castleblack.com or group:the-nights-watch. This comes into play later.
What I want to be able to do is the following type of query:
"Given that I have either a group id or a user id, return all documents of type a, b, or c where the group/user id is equal to or is a descendant of the document's owner."
In other words, I need to be able to return all documents that are owned by a particular user or group either explicitly or implicitly through a hierarchy.
I've considered solving this a couple different ways with no luck. Here are the two approaches I've tried:
Using a function within a query
With Dejan's help in an email thread, I was able to devise a function that would walk it's way down the ownership graph. What this attempted to do was build a flat array of IDs which represented explicit and implicit owners (i.e. root + descendants):
declare function hierarchy(doc, owners){
owners = owners || [];
while(doc != null) {
let ownerId = id(doc)
if(ownerId.startsWith('user:')) {
owners.push(ownerId);
} else if(ownerId.startsWith('group:')) {
owners.push(ownerId);
doc.Members.forEach(m => {
let owner = load(m, 'Users') || load(m, 'Groups');
owners = hierarchy(owner, owners);
});
}
}
return owners;
}
I had two issues with this. 1. I don't actually know how to use this in a query lol. I tried to use it as part of the where clause but apparently that's not allowed:
from #all_docs as d
where hierarchy(d) = 'group:my-group-d'
// error: method hierarchy not allowed
Or if I tried anything in the select statement, I got an error that I have exceeded the number of allowed statements.
As a custom index
I tried the same idea through a custom index. Essentially, I tried to create an index that would produce an array of IDs using roughly the same function above, so that I could just query where my id was in that array
map('#all_docs', function(doc) {
function hierarchy(n, graph) {
while(n != null) {
let ownerId = id(n);
if(ownerId.startsWith('user:')) {
graph.push(ownerId);
return graph;
} else if(ownerId.startsWith('group:')){
graph.push(ownerId);
n.Members.forEach(g => {
let owner = load(g, 'Groups') || load(g, 'Users');
hierarchy(owner, graph);
});
return graph;
}
}
}
function distinct(value, index, self){ return self.indexOf(value) === index; }
let ownerGraph = []
if(doc.Owner) {
let owner = load(doc.Owner, 'Groups') || load(doc.Owner, 'Users');
ownerGraph = hierarchy(owner, ownerGraph).filter(distinct);
}
return { Owners: ownerGraph };
})
// error: recursion is not allowed by the javascript host
The problem with this is that I'm getting an error that recursion is not allowed.
So I'm stumped now. Am I going about this wrong? I feel like this could be a subquery of sorts or a filter by function, but I'm not sure how to do that either. Am I going to have to do this in two separate queries (i.e. two round-trips), one to get the IDs and the other to get the docs?
Update 1
I've revised my attempt at the index to the following and I'm not getting the recursion error anymore, but assuming my queries are correct, it's not returning anything
// Entity/ByOwnerGraph
map('#all_docs', function(doc) {
function walkGraph(ownerId) {
let owners = []
let idsToProcess = [ownerId]
while(idsToProcess.length > 0) {
let current = idsToProcess.shift();
if(current.startsWith('user:')){
owners.push(current);
} else if(current.startsWith('group:')) {
owners.push(current);
let group = load(current, 'Groups')
if(!group) { continue; }
idsToProcess.concat(group.Members)
}
}
return owners;
}
let owners = [];
if(doc.Owner) {
owners.concat(walkGraph(doc.Owner))
}
return { Owners: owners };
})
// query (no results)
from index Entity/ByOwnerGraph as x
where x.Owners = "group:my-group-id"
// alternate query (no results)
from index Entity/ByOwnerGraph as x
where x.Owners ALL IN ("group:my-group-id")
I still can't use this approach in a query either as I get the same error that there are too many statements.
There is a data class as fruits.
data class Fruits(
val code: String, //Unique
val name: String
)
The base list indexed items with boolean variable is as below.
val indexList: MutableList<Boolean> = MutableList(baseFruitList.size) { false }
Now the Favourite Indexed list is as below
val favList: MutableList<Boolean> = MutableList(favFruitList.size) { true}
I want a combined full list which basically has the fav item indicated as true.
Ex:
baseFruitList = {[FT1,apple],[FT2,grapes],[FT3,banana],[FT4,mango],[FT5,pears]}
favList = {[FT2,grapes],[FT4,mango]}
The final index list should have
finalIndexed = {false,true,false,true,false}
How can we achieve in Kotlin, without iterating through each element.
You can do
val finalIndexed = baseFruitList.map { it in favList }
assuming, like #Tenfour04 is asking, that name is guaranteed to be a specific value (including matching case) for a specific code (since that combination is how a data class matches another, e.g. for checking if it's in another list)
If you can't guarantee that, this is safer:
val finalIndexed = baseFruitList.map { fruit ->
favList.any { fav.code == fruit.code }
}
but here you have to iterate over all the favs (at least until you find a match) looking to see if one has the code.
But really, if code is the unique identifier here, why not just store those in your favList?
favList = listOf("FT2", "FT4") // or a Set would be more efficient, and more correct!
val finalIndexed = baseFruitList.map { it.code in favList }
I don't know what you mean about "without iterating through each element" - if you mean without an explicit indexed for loop, then you can use these simple functions like I have here. But there's always some amount of iteration involved. Sets are always an option to help you minimise that
Kotlin has some pretty cool functions for collections. However, I have come across a problem in which the solution is not apparent to me.
I have a List of Objects. Those Objects have an ID field which coincides with a SQLite database. SQL operations are performed on the database, and a new list is generated. How can the index of an item from the new list be found based on the "ID" field (or any other field for that matter)?
the Collection.find{} function return the object, but not the index.
indexOfFirst can find the index of the first element of a collection that satisfies a specified predicate.
We have a DB SQlite that a call is made to to retrieve parentList We can obtain the items in the ArrayList with this type of code
fun onDoIt(view: View){
initDB()
for (t in 0..X-1) {
var N:String = parentList[t].dept
// NOTE two syntax here [t] and get(t)
if(t == 1){
var B:String = parentList[0].idD.toString()
println("$$$$$$$$$$$$$$$$$$$$$ ====== "+B)
}
var I:String = parentList.get(t).idD.toString()
println("################### id "+I+" for "+N)
}
}
private fun initDB() {
parentList = db.querySPDept()
if (parentList.isEmpty()) {
title = "No Records in DB"
} else {
X = parentList.size
println("**************************************** SIZE " + X)
title = "SP View Activity"
}
}
I use sqlJdbs query as a data provider for my CCC controls. I use geospatial request in my query that's why I cache my results(Cache=True). Otherwise the request made long.
It works fine. However I have to use parameters in my query to filter resulting rows:
SELECT ...
FROM ...
WHERE someField IN (${aoi_param})
Is there some way to cache full set of rows and then apply WHERE to cached results without rebuilding new cache for each set of values in the ${aoi_param}?
What is the best practice?
So, I am not really sure that it is the best practice, but I solved my problem this way:
I included aoi_param to the Listeners and Parameters of my chart control
Then I filtered data set in Post Fetch:
function f(data){
var _aoi_param = this.dashboard.getParameterValue('${p:aoi_param}');
function isInArray(myValue, myArray) {
var arrayLength = myArray.length;
for (var i = 0; i < arrayLength; i++) {
if (myValue == myArray[i]) return true;
}
return false;
}
function getFiltered(cdaData, filterArray) {
var allCdaData = cdaData;
cdaData = {
metadata: allCdaData.metadata,
resultset: allCdaData.resultset.filter(function(row){
// 2nd column is an AOI id in my dataset
return isInArray(row[2], filterArray);
})
};
return cdaData;
}
var dataFiltered = getFiltered(data, _aoi_param);
return dataFiltered;
}
excluded WHERE someField IN (${aoi_param}) from the query of my sql over sqlJdbc component
So I want to allow the user to conditionally turn columns on/off in a Cardboard app I built. I have two problems.
I tried using the 'columns' attribute in the config but I can't seem to find a default value for it that would allow ALL columns to display(All check boxes checked) based on the attribute, ie. the default behavior if I don't include 'columns' in the config object at all (tried null, [] but that displays NO columns).
So that gets to my second problem, if there is no default value is there a simple way to only change that value in the config object or do I have to encapsulate the entire variable in 'if-else' statements?
Finally if I have to manually build the string I need to parse the values of an existing custom attribute (a drop list) we have on the portfolio object. I can't seem to get the rally.forEach loop syntax right. Does someone have a simple example?
Thanks
Dax - Autodesk
I found a example in the online SDK from Rally that I could modify to answer the second part (This assumes a custom attribute on Portfolio item called "ADSK Kanban State" and will output values to console) :
var showAttributeValues = function(results) {
for (var property in results) {
for (var i=0 ; i < results[property].length ; i++) {
console.log("Attribute Value : " + results[property][i]);
}
}
};
var queryConfig = [];
queryConfig[0] = {
type: 'Portfolio Item',
key : 'eKanbanState',
attribute: 'ADSK Kanban State'
};
rallyDataSource.findAll(queryConfig, showAttributeValues);
rally.forEach loops over each key in the first argument and will execute the function passed as the second argument each time.
It will work with either objects or arrays.
For an array:
var array = [1];
rally.forEach(array, function(value, i) {
//value = 1
//i = 0
});
For an object:
var obj = {
foo: 'bar'
};
rally.forEach(obj, function(value, key) {
//value = 'bar'
//key = 'foo'
});
I think that the code to dynamically build a config using the "results" collection created by your query above and passed to your sample showAttributeValues callback, is going to look a lot like the example of dynamically building a set of Table columns as shown in:
Rally App SDK: Is there a way to have variable columns for table?
I'm envisioning something like the following:
// Dynamically build column config array for cardboard config
var columnsArray = new Array();
for (var property in results) {
for (var i=0 ; i < results[property].length ; i++) {
columnsArray.push("'" + results[property][i] + "'");
}
}
var cardboardConfig = {
{
attribute: 'eKanbanState',
columns: columnsArray,
// .. rest of config here
}
// .. (re)-construct cardboard...
Sounds like you're building a neat board. You'll have to provide the board with the list of columns to show each time (destroying the old board and creating a new one).
Example config:
{
attribute: 'ScheduleState'
columns: [
'In-Progress',
'Completed'
]
}