I wrote this query and as my understanding of the business rules has improved I have modified it.
In this most recent iteration I was testing to see if indeed I had some redundancy that could be removed. Let me first give you the query then the error.
public List<ExternalForums> GetAllExternalForums(int extforumBoardId)
{
List<ExternalForums> xtrnlfrm = new List<ExternalForums>();
var query = _forumExternalBoardsRepository.Table
.Where(id => id.Id == extforumBoardId)
.Select(ExtForum => ExtForum.ExternalForums);
foreach (ExternalForums item in query)
{
xtrnlfrm.Add(new ExternalForums { Id = item.Id , ForumName = item.ForumName, ForumUrl = item.ForumUrl });
}
return xtrnlfrm;
}
Now in case it isn't obvious the query select is returning List of ExternalForums. I then loop through said list and add the items to another List of ExternalForums object. This is the redundancy I was expecting to remove.
Precompiler was gtg so I ran through it one time to very everything was kosher before refactoring and ran into a strange error as I began the loop.
Unable to cast object of System.Collections.Generic.HashSet
NamSpcA.NamSpcB.ExternalForums to type NamSpcA.NamSpcB.ExternalForums.
Huh? They are the same object types.
So am I doing something wrong in the way I am projecting my select?
TIA
var query = _forumExternalBoardsRepository.Table
.Where(id => id.Id == extforumBoardId)
.Select(ExtForum => ExtForum.ExternalForums);
This query returns IEnumerable<T> where T is type of ExtForum.ExternalForums property, which I would expect to be another collection, this time of ExternalForum. And the error message matches that, saying you have IEnumerable<HashSet<ExternalForums>>.
If you need that collection of collections to be flattened into one big collection of ExternalForums use SelectMany instead:
var query = _forumExternalBoardsRepository.Table
.Where(id => id.Id == extforumBoardId)
.SelectMany(ExtForum => ExtForum.ExternalForums);
Related
I am new to Gatling, I am trying to do the performance testing for couple of rest calls. In my scenario I need to extract a value from json response of the 1st call and add those values to the list after looping for few times. Again after looping for few times and adding the values into the list, I want to reuse each value in my next rest call by iterating over the values in the list. Can anyone please suggest on how to implement this. I tried something as below,
var datasetIdList = List.empty[String]
val datasetidsFeeder = datasetIdList.map(datasetId => Map("datasetId" -> datasetId)).iterator
def createData() = {
repeat(20){
feed("").exec(http("create dataset").post("/create/data").header("content-type", "application/json")
.body(StringBody("""{"name":"name"}"""))
.asJson.check(jsonPath("$.id").saveAs("userId"))))
.exec(session => { var usrid = session("userId").as[String].trim
datasetIdList:+= usrid session})
}}
def upload()= feed(datasetidsFeeder).exec(http("file upload").post("/compute-metaservice/datasets/${datasetId}/uploadFile")
.formUpload("File","./src/test/resources/data/File.csv")
.header("content-type","multipart/form-data")
.check(status is 200))
val scn = scenario("create data and upload").exec(createData()).exec(upload())
setUp(scn.inject(atOnceUsers(1))).protocols(httpConf)
}
I am seeing an exception that ListFeeder is empty when trying to run above script. Can someone please help
Updated Code:
class ParallelcallsSimulation extends Simulation{
var idNumbers = (1 to 50).iterator
val customFeeder = Iterator.continually(Map(
"name" -> ("test_gatling_"+ idNumbers.next())
))
val httpConf = http.baseUrl("http://localhost:8080")
.header("Authorization","Bearer 6a4aee03-9172-4e31-a784-39dea65e9063")
def createDatasetsAndUpload() = {
repeat(3) {
//create dataset
feed(customFeeder).exec(http("create data").post("/create/data").header("content-type", "application/json")
.body(StringBody("""{ "name": "${name}","description": "create data and upload file"}"""))
.asJson.check(jsonPath("$.id").saveAs("userId")))
.exec(session => {
val name = session("name").asOption[String]
println(name.getOrElse("COULD NOT FIND NAME"))
val userId = session("userId").as[String].trim
println("%%%%% User ID ====>"+userId)
val datasetIdList = session("datasetIdList").asOption[List[_]].getOrElse(Nil)
session.set("datasetIdList", userId :: datasetIdList)
})
}
}
// File Upload
def fileUpload() = foreach("${datasetIdList}","datasetId"){
exec(http("file upload").post("/uploadFile")
.formUpload("File","./src/test/resources/data/File.csv")
.header("content-type","multipart/form-data")
.check(status is 200))
}
def getDataSetId() = foreach("${datasetIdList}","datasetId"){
exec(http("get datasetId")
.get("/get/data/${datasetId}")
.header("content-type","application/json")
.asJson.check(jsonPath("$.dlp.dlp_job_status").optional
.saveAs("dlpJobStatus")).check(status is 200)
).exec(session => {
val datastId = session("datasetId").asOption[String]
println("request for datasetId >>>>>>>>"+datastId.getOrElse("datasetId not found"))
val jobStatus = session("dlpJobStatus").asOption[String]
println("JOB STATUS:::>>>>>>>>>>"+jobStatus.getOrElse("Dlp Job Status not Found"))
println("Time: >>>>>>"+System.currentTimeMillis())
session
}).pause(10)
}
val scn1 = scenario("create multiple datasets and upload").exec(createDatasetsAndUpload()).exec(fileUpload())
val scn2 = scenario("get datasetId").pause(100).exec(getDataSetId())
setUp(scn1.inject(atOnceUsers(1)),scn2.inject(atOnceUsers(1))).protocols(httpConf)
}
I see below error when I try to execute above script
[ERROR] i.g.c.s.LoopBlock$ - Condition evaluation crashed with message 'No attribute named 'datasetIdList' is defined', exiting loop
var datasetIdList = List.empty[String] defines a mutable variable pointing to a immutable list.
val datasetidsFeeder = datasetIdList.map(datasetId => Map("datasetId" -> datasetId)).iterator uses the immutable list. Further changes to datasetIdList is irrelevant to datasetidsFeeder.
Mutating a global variable with your virtual user is usually not a good idea.
You can save the value into the user's session instead.
In the exec block, you can write:
val userId = session("userId").as[String].trim
val datasetIdList = session("datasetIdList").asOption[List[_]].getOrElse(Nil)
session.set("datasetIdList", userId :: datasetIdList)
Then you can use foreach to iterate them all without using a feeder at all.
foreach("${datasetIdList}", "datasetId") {
exec(http("file upload")
...
}
You should put more work in your question.
Your code is not syntax-highlighted, and is formatted poorly.
You said "I am seeing an exception that ListFeeder is empty" but the words "ListFeeder" are not seen anywhere.
You should post the error message so that it's easier to see what went wrong.
In the documentation linked, there is a Warning. Quoted below:
Session instances are immutable!
Why is that so? Because Sessions are messages that are dealt with in a multi-threaded concurrent way, so immutability is the best way to deal with state without relying on synchronization and blocking.
A very common pitfall is to forget that set and setAll actually return new instances.
This is why the code in the updated question doesn't update the list.
session => {
...
session.set("datasetIdList", userId :: datasetIdList)
println("%%%% List =====>>>" + datasetIdList.toString())
session
}
The updated session is simply discarded. And the original session is returned in the anonymous function.
I have two queries:
a) select id from ingredietns where name = my_param;
b) select word_id from synonyms where name = my_param;
Both return 0 or 1 row. I can also add limit 1 if needed (or in knex first()).
I can translate each into knex like this:
knex("ingredients").select('id').where('name', my_param) //do we need first()?
knex("synonyms").select('word_id').where('name', my_param) //do we need first()?
I need function called "ingredientGetOrCreate(my_param)". This function would
a) check if any of above queries return result
b) if any of these return, then return ingredients.id or synonyms.word_id - only one could be returned
c) if record doesn't eixst in any of tables, I need to do knex inesrt aand return newly added id from function
d) later I am not sure I also understand how to call this newly create function.
Function ingredientGetOrCreate would be used later as seperate function or in the following scenario (like "loop") that doesn't work for me either:
knex("products") // for each product
.select("id", "name")
.map(function (row) {
var descriptionSplitByCommas = row.desc.split(",");
Promise.all(descriptionSplitByCommas
.map(function (my_param) {
// here it comes - call method for each param and do insert
ingredientGetOrCreate(my_param)
.then(function (id_of_ingredient) {
knex('ingredients_products').insert({ id_of_ingredient });
});
...
I am stuck with knex and Promise queries because of asynchronouse part. Any clues, please?
I though I can somehow use Promise.all or Promise.some to call both queries.
P.S. This is my first day with nodejs, Promise and knex.
As far as I decode your question, it consists of two parts:
(1) You need to implement upsert logic (get-or-create logic).
(2) Your get part requires to query not a single table, but a pair of tables in specific order. Table names imply that this is some sort of aliasing engine inside of your application.
Let's start with (2). This could definitely be solved with two queries, just like you sense it.
function pick_name (rows)
{
if (! rows.length) return null
return rows[0].name
}
// you can sequence queries
function ingredient_get (name)
{
return knex('ingredients')
.select('id').where('name', name)
.then(pick_name)
.then(name =>
{
if (name) return name
return knex('synonyms')
.select('word_id').where('name', name)
.then(pick_name)
})
}
// or run em parallel
function ingredient_get (name)
{
var q_ingredients = knex('ingredients')
.select('id').where('name', name)
.then(pick_name)
var q_synonyms = knex('synonyms')
.select('word_id').where('name', name)
.then(pick_name)
return Promise.all([ q_ingredients, q_synonyms ])
.then(([name1, name2]) =>
{
return name1 || name2
})
}
Important notions here:
Both forms works well and return first occurence or JS' null.
First form optimizes count of queries to DB.
Second form optimizes answer time.
However, you can go deeper and use more SQL. There's a special tool for such task called COALESCE. You can consult your SQL documentation, here's COLASCE of PostgreSQL 9. The main idea of COALESCE is to return first non-NULL argument or NULL otherwise. So, you can leverage this to optimize both queries and answer time.
function ingredient_get (name)
{
// preparing but not executing both queries
var q_ingredients = knex('ingredients')
.select('id').where('name', name)
var q_synonyms = knex('synonyms')
.select('word_id').where('name', name)
// put them in COALESCE
return knex.raw('SELECT COALESCE(?, ?) AS name', [ q_ingredients, q_synonyms ])
.then(pick_name)
This solution guarantees single query and furthermore DB engine can optimize execution in any way it sees appropriate.
Now let's solve (1): We now got ingredient_get(name) which returns Promise<string | null>. We can use its output to activate create logic or return our value.
function ingredient_get_or_create (name, data)
{
return ingredient_get(name)
.then(name =>
{
if (name) return name
// …do your insert logic here
return knex('ingredients').insert({ name, ...data })
// guarantee homohenic output across get/create calls:
.then(() => name)
})
}
Now ingredient_get_or_create do your desired upsert logic.
UPD1:
We already got ingredient_get_or_create which returns Promise<name> in any scenario (both get or create).
a) If you need to do any specific logic after that you can just use then:
ingredient_get_or_create(…)
.then(() => knex('another_table').insert(…))
.then(/* another logic after all */)
In promise language that means «do that action (then) if previous was OK (ingredient_get_or_create)». In most of the cases that is what you need.
b) To implement for-loop in promises you got multiple different idioms:
// use some form of parallelism
var qs = [ 'name1', 'name2', 'name3' ]
.map(name =>
{
return ingredient_get_or_create(name, data)
})
var q = Promise.all(qs)
Please, note, that this is an agressive parallelism and you'll get maximum of parallel queries as your input array provides.
If it's not desired, you need to limit parallelism or even run tasks sequentially. Bluebird's Promise.map is a way to run map which analogous to example above but with concurrency option available. Consider the docs for details.
There's also Bluebird's Promise.mapSeries which conceptually is an analogue to for-loop but with promises. It's like map which runs sequentially. Look the docs for details.
Promise.mapSeries([ 'name1', 'name2', 'name3' ],
(name) => ingredient_get_or_create(name, data))
.then(/* logic after all mapSeries are OK */)
I believe the last is what you need.
I use CSOM .NET to load task objects from Project Server 2013, and I need to
filter tasks so that only a subset of them is returned, and
load only a subset of task columns, specified at runtime by the user.
I found this post that shows how to load a dynamic set of columns, and it works nicely for my second requirement. However, I cannot figure out a workable LINQ syntax to combine both column selection and row filtering.
In the example below, I need to load only those "rows" for summary tasks (where t.IsSummary is true), and I want to load only the Name, Start, and Finish columns.
The following code from the referenced post loads just the three columns that I need:
foreach (string fieldName in new List<string>(){"Name","Start","Finish"});
{
ctx.Load(ctx.Tasks,c => c.Include(t => t[fieldName]));
}
ctx.ExecuteQuery();
But when I try to combine where() and include() in the only syntax that makes sense to me, I get InvalidQueryExpressionException on second iteration through the foreach loop: "The query expression is not supported."
foreach (string fieldName in new List<string>(){"Name","Start","Finish"});
{
ctx.Load(ctx.Tasks,
c => c.Where(t => t.IsSummary),
c => c.Include(t => t[fieldName])
);
}
ctx.ExecuteQuery();
I get the same error if I reverse the order of where and include clauses. If I pull the where clause outside of the loop over field names and make it a separate Load call, the summary-task row filtering works, but I lose the dynamic selection of tasks fields. There must be a syntax in LINQ for CSOM that meets both requirements. What is the correct syntax to do this type of query?
The following example demonstrates how to apply select and filter operators in SharePoint CSOM API:
var list = ctx.Web.Lists.GetByTitle(listTitle);
var items = list.GetItems(CamlQuery.CreateAllItemsQuery());
var result = ctx.LoadQuery(items.Where(i => (bool)i["IsSummary"]).Include(i => i["Name"], i => i["Start"], i => i["Finish"]));
ctx.ExecuteQuery();
foreach (var item in result)
{
Console.WriteLine(item["Name"]);
}
So, i believe the following expression is supported in Project Server CSOM API:
var result = ctx.LoadQuery(ctx.Tasks.Where(t => (bool)t["IsSummary"]).Include(t => i["Name"], t => t["Start"], t => t["Finish"]));
ctx.ExecuteQuery();
I answered this myself by using expression trees, which let you filter a set of rows and select a set of columns based on parameters that are only known at runtime. In the example below, I simulate finding out at runtime that I need to filter the tasks on the IsSummary column and that I should retrieve only the five columns Id, Name, Start, IsSubProject, and Finish. Here's the code:
using System.Linq.Expressions;
// Input parms discovered at runtime
string filterColumnName = "IsSummary";
List<string> columnNames = new List<string>(
new[] { "Id", "Name", "Start", "IsSubProject", "Finish" });
// Get the client object for the Published Project matching projGuid
ctx.Load(ctx.Projects, c => c.Where(p => p.Id == projGuid));
ctx.ExecuteQuery();
PublishedProject proj = ctx.Projects.Single();
// Compute the expression tree for filtering the task rows
var taskParm = Expression.Parameter(typeof(PublishedTask), "t");
var predicate = Expression.PropertyOrField(taskParm, filterColumnName);
var filterExpression = Expression.Lambda<
Func<PublishedTask, bool>>(predicate, taskParm);
// Dynamically generate expression tree for each column to be included
var colSelectionList = new List<Expression<
Func<PublishedTask, object>>>();
foreach (var colName in columnNames)
{
var fldExpr = Expression.PropertyOrField(taskParm, colName);
var fldAsObjExpr = Expression.Convert(fldExpr, typeof(object));
var colSelectorExpr = Expression.Lambda<
Func<PublishedTask, object>>(fldAsObjExpr, taskParm);
colSelectionList.Add(colSelectorExpr);
}
// Create query using LoadQuery (Load does not work here)
var taskList = ctx.LoadQuery(proj.Tasks
.Where(filterExpression)
.Include(colSelectionList.ToArray())
);
// Execute the query
ctx.ExecuteQuery();
// taskList now contains just the filtered rows and selected columns
I hope this helps someone else who is stuck on using CSOM to do this for Project Server. I found these two references helpful:
At MSDN
and at Second Life of a Hungarian SharePoint Geek
..Jim
Our code has a SqlExpression, which at its bare minimum is something like:
var q = db.From<Users>();
q.Where(u => u.Age == 25);
totalRecords = db.Scalar<int>(q.ToCountStatement());
q.ToCountStatement() generates the following query:
SELECT COUNT(*) FROM "Users" WHERE ("Age" = #0)
However, db.Scalar() throws an exception: Must declare the scalar variable "#0". This has started occurring in recent versions (tested in 4.0.54). The same code was working fine until v4.0.50. I've checked the release notes, but couldn't find a related change.
Even passing a parameter throws the same exception:
totalRecords = db.Scalar<int>(q.ToCountStatement(), 25);
Is it a bug, or my oversight?
Secondly, is it possible to get q.ToCountStatement() to generate a more optimized query with COUNT(Age) or COUNT([PrimaryKey]) instead of COUNT(*)?
Now that OrmLite defaults to parameterized queries you also need to provide the queries db parameters when executing a query (if you've specified any params), e.g:
var q = db.From<Users>().Where(u => u.Age == 25);
var count = db.Scalar<int>(q.ToCountStatement(), q.Params);
You can also use OrmLite's explicit Count() API's, e.g:
db.Count<User>(x => x.Age == 25);
Or with a typed SqlExpression:
var q = db.From<User>().Where(x => x.Age == 25);
db.Count(q);
Otherwise another way to specify db params is to use an anonymous object, e.g:
db.Scalar<int>("SELECT COUNT(*) FROM Users WHERE Age=#age", new { age = 25});
Given a collection of items { url: 'http://blah' }. How can I tell if a record exists where the url is "http://stackoverflow.com"?
P.s. I am communicating with the c# driver
For any of the previous suggestions to be efficient you should be sure that there is an index on the url element. Otherwise a full collection scan will be required.
If you only expect the answer to be 0 or 1, count is probably the most efficient approach. If you think the count will be very large and all you really care about is whether there is one or more, FindOne is the most efficient approach.
It probably doesn't matter that FindOne returns the whole document unless the document is actually rather large. In that case you could tell the server to only return one field (the _id seems the most likely candidate):
var query = Query.EQ("url", "http://stackoverflow.com");
var fields = Fields.Include("_id");
var res = collection.Find(query).SetFields(fields).SetLimit(1).FirstOrDefault();
if (res == null) {
// no match found
}
you simply need check count of items returned by the query:
int count = collection.FindAs<Item>(Query.EQ("url", "http://stackoverflow.com")).Count();
if(count > 0)
{
//do some stuff
}
IMongoQuery query = Query.EQ("url", "http://stackoverflow.com");
var res = collection.FindOne(query);
if(res == null)//don't exist
{
}
Existence of Key in MongoDB can check by using Exists and second parameter as true or false
var filter = builder.Exists("style", false);
var RetrievedData = collection.Find(filter).ToList()
Refference Link