I have a situation where my user is presented with a grid, and it, by default, will just get the first 15 results. However they may type in a name and search for an item across all pages.
Alone, either of these works fine, but I am trying to figure out how to make them work as a single query. This is basically what it looks like...
// find a filter if the user is searching
var filters = request.Filters.ToFilters();
// determine the name to search by
var name = filters.Count > 0 ? filters[0] : null;
// we need to be able to catch some query statistics to make sure that the
// grid view is complete and accurate
RavenQueryStatistics statistics;
// try to query the items listing as quickly as we can, getting only the
// page we want out of it
var items = RavenSession
.Query<Models.Items.Item>()
.Statistics(out statistics) // output our query statistics
.Search(n => n.Name, name)
.Skip((request.Page - 1) * request.PageSize)
.Take(request.PageSize)
.ToArray();
// we need to store the total results so that we can keep the grid up to date
var totalResults = statistics.TotalResults;
return Json(new { data = items, total = totalResults }, JsonRequestBehavior.AllowGet);
The problem is that if no name is given, it does not return anything; Which is not the desired result. (Searching by 'null' doesn't work, obviously.)
Do something like this:
var q= RavenSession
.Query<Models.Items.Item>()
.Statistics(out statistics); // output our query statistics
if(string.IsNullOrEmpty(name) == false)
q = q.Search(n => n.Name, name);
var items = q.Skip((request.Page - 1) * request.PageSize)
.Take(request.PageSize)
.ToArray();
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.
I have the following query:
var list = repositoy.Query<MyClass>.Select(domain => new MyDto()
{
Id = domain.Id,
StringComma = string.Join(",", domain.MyList.Select(y => y.Name))
});
That works great:
list.ToList();
But if I try to get the Count I got an exception:
list.Count();
Exception
NHibernate.Hql.Ast.ANTLR.QuerySyntaxException
A recognition error occurred. [.Count[MyDto](.Select[MyClass,MyDto](NHibernate.Linq.NhQueryable`1[MyClass], Quote((domain, ) => (new MyDto()domain.Iddomain.Name.Join(p1, .Select[MyListClass,System.String](domain.MyList, (y, ) => (y.Name), ), ))), ), )]
Any idea how to fix that without using ToList ?
The point is, that we should NOT call Count() over projection. So this will work
var query = repositoy.Query<MyClass>;
var list = query.Select(domain => new MyDto()
{
Id = domain.Id,
StringComma = string.Join(",", domain.MyList.Select(y => y.Name))
});
var count = query.Count();
When we use ICriteria query, the proper syntax would be
var criteria = ... // criteria, with WHERE, SELECT, ORDER BY...
// HERE cleaned up, just to contain WHERE clause
var totalCountCriteria = CriteriaTransformer.TransformToRowCount(criteria);
So, for Count - use the most simple query, i.e. containing the same JOINs and WHERE part
If you really don't need the results, but only the count, then you shouldn't even bother writing the .Select() clause. Radim's answer as posted is a good way to both get the results and the count, but if your database supports it, use future queries to execute both in the same roundtrip to the database:
var query = repository.Query<MyClass>;
var list = query.Select(domain => new MyDto()
{
Id = domain.Id,
StringComma = string.Join(",", domain.MyList.Select(y => y.Name))
}).ToFuture();
var countFuture = query.Count().ToFutureValue();
int actualCount = countFuture.Value; //queries are actually executed here
Note that there in NH prior to 3.3.3, this would still execute two round-trips (see https://nhibernate.jira.com/browse/NH-3184), but it would work, and if you ever upgrade NH, you get a (minor) performance boost.
So I have a standard service reference proxy calss for MS CRM 2013 (i.e. right-click add reference etc...) I then found the limitation that CRM data calls limit to 50 results and I wanted to get the full list of results. I found two methods, one looks more correct, but doesn't seem to work. I was wondering why it didn't and/or if there was something I'm doing incorrectly.
Basic setup and process
crmService = new CrmServiceReference.MyContext(new Uri(crmWebServicesUrl));
crmService.Credentials = System.Net.CredentialCache.DefaultCredentials;
var accountAnnotations = crmService.AccountSet.Where(a => a.AccountNumber = accountNumber).Select(a => a.Account_Annotation).FirstOrDefault();
Using Continuation (something I want to work, but looks like it doesn't)
while (accountAnnotations.Continuation != null)
{
accountAnnotations.Load(crmService.Execute<Annotation>(accountAnnotations.Continuation.NextLinkUri));
}
using that method .Continuation is always null and accountAnnotations.Count is always 50 (but there are more than 50 records)
After struggling with .Continutation for a while I've come up with the following alternative method (but it seems "not good")
var accountAnnotationData = accountAnnotations.ToList();
var accountAnnotationFinal = accountAnnotations.ToList();
var index = 1;
while (accountAnnotationData.Count == 50)
{
accountAnnotationData = (from a in crmService.AnnotationSet
where a.ObjectId.Id == accountAnnotationData.First().ObjectId.Id
select a).Skip(50 * index).ToList();
accountAnnotationFinal = accountAnnotationFinal.Union(accountAnnotationData).ToList();
index++;
}
So the second method seems to work, but for any number of reasons it doesn't seem like the best. Is there a reason .Continuation is always null? Is there some setup step I'm missing or some nice way to do this?
The way to get the records from CRM is to use paging here is an example with a query expression but you can also use fetchXML if you want
// Query using the paging cookie.
// Define the paging attributes.
// The number of records per page to retrieve.
int fetchCount = 3;
// Initialize the page number.
int pageNumber = 1;
// Initialize the number of records.
int recordCount = 0;
// Define the condition expression for retrieving records.
ConditionExpression pagecondition = new ConditionExpression();
pagecondition.AttributeName = "address1_stateorprovince";
pagecondition.Operator = ConditionOperator.Equal;
pagecondition.Values.Add("WA");
// Define the order expression to retrieve the records.
OrderExpression order = new OrderExpression();
order.AttributeName = "name";
order.OrderType = OrderType.Ascending;
// Create the query expression and add condition.
QueryExpression pagequery = new QueryExpression();
pagequery.EntityName = "account";
pagequery.Criteria.AddCondition(pagecondition);
pagequery.Orders.Add(order);
pagequery.ColumnSet.AddColumns("name", "address1_stateorprovince", "emailaddress1", "accountid");
// Assign the pageinfo properties to the query expression.
pagequery.PageInfo = new PagingInfo();
pagequery.PageInfo.Count = fetchCount;
pagequery.PageInfo.PageNumber = pageNumber;
// The current paging cookie. When retrieving the first page,
// pagingCookie should be null.
pagequery.PageInfo.PagingCookie = null;
Console.WriteLine("#\tAccount Name\t\t\tEmail Address");while (true)
{
// Retrieve the page.
EntityCollection results = _serviceProxy.RetrieveMultiple(pagequery);
if (results.Entities != null)
{
// Retrieve all records from the result set.
foreach (Account acct in results.Entities)
{
Console.WriteLine("{0}.\t{1}\t\t{2}",
++recordCount,
acct.EMailAddress1,
acct.Name);
}
}
// Check for more records, if it returns true.
if (results.MoreRecords)
{
// Increment the page number to retrieve the next page.
pagequery.PageInfo.PageNumber++;
// Set the paging cookie to the paging cookie returned from current results.
pagequery.PageInfo.PagingCookie = results.PagingCookie;
}
else
{
// If no more records are in the result nodes, exit the loop.
break;
}
}
I am looking for a way to return the value of a precise column in the first result of a query.
The query result contains always 1 row containing the following columns :
ID
PW
RANK
I am trying to only get the rank value in order to push it into a session variable.
I tried messing with :
$row-> $query->row();
But then I don't know how to get only the value of the rank column. Ideally, I would want to get that value, then return it to allow my controller to set it in the session variable ( doing it in the model would be easier but would break the MVC pattern, right ?)
How can I do this ?
Thanks
Have the controller call a function in the model that return that value. Let's say the model has a function name get_rank()
public function get_rank($id)
{
// assumes your ID is an int
$id = (int)$id;
// avoid wasting a query
if ($id < 1) return FALSE;
// build query
$this->db->select('rank');
$this->db->from('YOUR_TABLE');
$this->db->where('id', $id);
// maybe some sorting / limiting here if you need it
// get result
$rs = $this->db->get();
if ($rs->num_rows() > 0)
{
// just get the first row
$row = $rs->row();
return $row->rank;
}
return FALSE;
}
I want to fetch Hierarchical/Tree data something like below from a Table which has following definiton.
Tree Table:
"""""""""""
Id |ParentId
"""""""""""
Work1|null
Work2|Work1
Work3|Work2
...
Required Query result Data (no need to be tabbed)- If I Pick 'Work1' I should complete Ids which are under its root something like below. If I pick 'Work2' then also I should complete Ids above and below its root.
> Work1
----------
> Work2
----------
> Work3
---------
What is the best way in NHibernate to fetch data in the above scenario in optimized manner.
To find out what the "best way" is, more information regarding the actual scenario would be needed. What kind of "optimization" are you looking for? Minimal amount of data (only the rows you are really going to need) or minimal number of SQL queries (preferably one roundtrip to the database) or any other?
Scenario 1: Menu or tree structure that is loaded once and kept in memory for longer periods of time (not a list that updates every few seconds). Small number of rows in the table (small is relative but I'd say anything below 200).
In this case I would just get the whole table with one query like this:
var items = session.Query<Work>()
.Fetch(c => c.ParentWork)
.Fetch(c => c.ChildWorks).ToList();
var item = session.Get<Work>(id);
This will result in a single SQL query which simply loads all the rows from the table. item will contain the complete tree (parents, grandparents, children, etc.).
Scenario 2: Large number of rows and only a fraction of rows needed. Only few levels in the hierarchy are to be expected.
In this case, just load the item and let NHibernate to the rest with lazy loading or force it to load everything by writing a recursive method to traverse parents and children. This will cause a N+1 select, which may or may not be slower than scenario 1 (depending on your data).
Here is a quick hack demonstrating this:
var item = session.Get<Work>(id);
Work parent = item.ParentWork;
Work root = item;
// find the root item
while (parent != null)
{
root = parent;
parent = parent.ParentWork;
}
// scan the whole tree
this.ScanChildren(root);
// -----
private void ScanChildren(Work item)
{
if (item == null)
{
return;
}
foreach (Work child in item.ChildWorks)
{
string name = child.Name;
this.ScanChildren(child);
}
}
Edit:
Scenario 3: Huge amount of data. Minimal number of queries and minimal amount of data.
In this case, I would think not of a tree structure but of having layers of data that we load one after another.
var work = repo.Session.Get<Work>(id);
// get root of that Work
Work parent = work.ParentWork;
Work root = work;
while (parent != null)
{
root = parent;
parent = parent.ParentWork;
}
// Get all the Works for each level
IList<Work> worksAll = new List<Work>() { root };
IList<Work> worksPerLevel = new List<Work>() { root };
// get each level until we don't have any more Works in the next level
int count = worksPerLevel.Count;
while (count > 0)
{
worksPerLevel = this.GetChildren(session, worksPerLevel);
// add the Works to our list of all Works
worksPerLevel.ForEach(c => worksAll.Add(c));
count = worksPerLevel.Count;
}
// here you can get the names of the Works or whatever
foreach (Work c in worksAll)
{
string s = c.Name;
}
// this methods gets the Works in the next level and returns them
private IList<Work> GetChildren(ISession session, IList<Work> worksPerLevel)
{
IList<Work> result = new List<Work>();
// get the IDs for the works in this level
IList<int> ids = worksPerLevel.Select(c => c.Id).ToList();
// use a WHERE IN clause do get the Works
// with the ParentId of Works in the current level
result = session.QueryOver<Work>()
.Where(
NHibernate.Criterion.Restrictions.InG<int>(
NHibernate.Criterion.Projections.Property<Work>(
c => c.ParentWork.Id),
ids)
)
.Fetch(c => c.ChildWorks).Eager // this will prevent the N+1 problem
.List();
return result;
}
This solution will not cause a N+1 problem, because we use an eager load for the children, so NHibernate will know the state of the child lists and not hit the DB again. You will only get x+y selects, where x is the number of selects to find the root Work and y is the number of levels (max depth of he tree).