I need most elegant solution for dynamic selecting/grouping/ordering via Linq2Entities (VB.NET/VS2012).
And I'm trying to use System.Linq.Dynamic library (http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx)
This construсtion works fine
Dim testQuery= testDB.testTable.Select("New(Field1)").GroupBy("New(Field1)", "it")
But this one (found this example somewhere on blogs/SO) generates error:
Dim testQuery= testDB.testTable.Select("New(Field1, Count())").GroupBy("New(Field1, Count())", "it")
The error is "No applicable method 'Count' exists in type 'testTable'"
I know that this library was born dead, but official MS solution for dynamic queries with expressions-trees is kinda scary. :-)
If your aim is to retrieve the count of rows in testTable for each value of Field1, then I would have thought you want to firstly GroupBy Field1, then Select afterwards. So basically reverse the order of your Select and GroupBy and remove the Count() from the GroupBy.
Related
The below query i want to add allowDiskUse true. I am able to add allowDiskUsage to aggregation query but not able to find a solution for find method
Query query = new Query().with(pageable).addCriteria(criteria).collation(collation);
mongoOperations.find(query, RuntimeApplication.class, RUNTIME_APP);
I want to know is that possible to add allowDiskUsage to find method or i need to change query to aggregation.
i just found in below query from internet. but i am not getting how to convert it into spring boot
db.collection.find(<match>).sort(<sort>).allowDiskUse()
What kind of spring-data version are you using? You should be able to add allowDiskUse to the Query object just like this:
val query = Query()
.with(Pageable.ofSize(1))
.addCriteria(Criteria())
.allowDiskUse(true)
And then afterwards use the query with find for instance with mongoTemplate.
Here is the documentation: https://javadoc.io/doc/org.springframework.data/spring-data-mongodb/latest/org/springframework/data/mongodb/core/query/Query.html
I am using PyPika (version 0.37.6) to create queries to be used in BigQuery. I am building up a query that has two WITH clauses, and one clause is dependent on the other. Due to the dynamic nature of my application, I do not have control over the order in which those WITH clauses are added to the query.
Here is example working code:
a_alias = AliasedQuery("a")
b_alias = AliasedQuery("b")
a_subq = Query.select(Term.wrap_constant("1").as_("z")).select(Term.wrap_constant("2").as_("y"))
b_subq = Query.from_(a_alias).select("z")
q = Query.with_(a_subq, "a").from_(a_alias).select(a_alias.y)
q = q.with_(b_subq, "b").from_(b_alias).select(b_alias.z)
sql = q.get_sql(quote_char=None)
That generates a working query:
WITH a AS (SELECT '1' z,'2' y) ,b AS (SELECT a.z FROM a) SELECT a.y,b.z FROM a,b
However, if I add the b WITH clause first, then since a is not yet defined, the resulting query:
WITH b AS (SELECT a.z FROM a), a AS (SELECT '1' z,'2' y) SELECT a.y,b.z FROM a,b
does not work. Since BigQuery does not support WITH RECURSIVE, that is not an option for me.
Is there any way to control the order of the WITH clauses? I see the _with list in the QueryBuilder (the type of variable q), but since that's a private variable, I don't want to rely on that, especially as new versions of PyPika may not operate the same way.
One way I tried to do this is to always insert the first WITH clause at the beginning of the _with list, like this:
q._with.insert(0, q._with.pop())
Although this works, I'd like to use a PyPika supported way to do that.
In a related question, is there a supported way within PyPika to see what has already been added to the select list or other parts of the query? I noticed the q.selects member variable, but selects is not part of the public documentation. Using q.selects did not actually work for me when using our project's Python version (3.6) even though it did work in Python 3.7. The code I was trying to use is:
if any(field.name == "date" for field in q.selects if isinstance(field, Field))
The error I got was as follows:
def __getitem__(self, item: slice) -> "BetweenCriterion":
if not isinstance(item, slice):
> raise TypeError("Field' object is not subscriptable")
Thank you in advance for your help.
I could not figure out how to control the order of the WITH clauses after calling query.with_() (except for the hack already noted). As a result, I restructured my application to get around this problem. I am now calling query.with_() before building up the rest of the query.
This also made my related question moot, because I no longer need to see what I've already added to the query.
I am trying to learn a bit about ling. in the code below, I'm trying to retrieve records that have an activeuntil date which after the current date.
Dim context As DynamicsCRMEntities = New DynamicsCRMEntities()
Dim CustomerNoticeQuery = From NewsArticles In context.BusinessUnitNewsArticles Where NewsArticles.NewsArticle Like "customer" Select NewsArticles.ArticleTitle, NewsArticles.NewsArticle, NewsArticles.ActiveUntil
For Each result In CustomerNoticeQuery
If Date.Now.Date >= result.ActiveUntil Then
CustomerNotice.Text = result.NewsArticle.ToString
End If
Next
I keep running into this error but cannot get my head around it
System.NotSupportedException: 'LINQ to Entities does not recognize the method 'Boolean LikeString(System.String, System.String, Microsoft.VisualBasic.CompareMethod)' method, and this method cannot be translated into a store expression.'
The Like operator you are using there is VB-specific and, as the error message says, is not supported by EF. You need to use standard .NET functionality that the LINQ to Entities provider understands. If you want to do a partial match on Strings, that means using String.Contains:
Dim CustomerNoticeQuery = From NewsArticles In context.BusinessUnitNewsArticles
Where NewsArticles.NewsArticle.Contains("customer")
Select NewsArticles.ArticleTitle, NewsArticles.NewsArticle, NewsArticles.ActiveUntil
You really ought to break your LINQ queries over multiple lines like that too, for the sake of readability.
Note that that addresses your actual issue, which has nothing to do with dates, so the date part to the question was completely irrelevant. That said, why would you do a query with a Where clause and then use a loop to filter the results of that query? Why would you not include the additional filter in the Where clause? I'd also consider using a better subject variable name in the query:
Dim today = Date.Today
Dim CustomerNoticeQuery = From article In context.BusinessUnitNewsArticles
Where article.NewsArticle.Contains("customer")
And article.ActiveUntil < today
Select article.ArticleTitle, article.NewsArticle, article.ActiveUntil
I was wondering if there is a way to use a select statement with a where clause similar to this way that does not seem to work for me in Ruby version 2.0/Rails 4.0 trying to retrieve a single record string value of a city where the building name is a certain name:
building_city = Building.select(:city).where(building_name: building).uniq
I have also tried:
building_city = Building.select(:city).where(building_name: building).distinct
Currently I have my code working like this:
building_city = Building.where(building_name: building).first
This grabs an entire Building object, and then I can call the city by doing a:
building_city.city
This works fine with what I am trying to achieve, but I was wondering if there is a smarter way to do this. Specifically, I was wondering if there is a way to grab only the string value of a city where the building name equals a certain building and store it into a variable?
Any help/advice is greatly appreciated! :)
Are you perhaps looking for pluck? Something like:
cities = Building.where(building_name: building).uniq.pluck(:city)
That will perform this SQL:
select distinct city from buildings where building_name = '...'
and give you the cities as an array of strings. You'll still get an array but a quick first call will take care of that if you're certain that there will only be one entry.
building_city = Building.select(:city, :building_name).where(building_name: building).uniq — you need to include the building_name
city = Building.where(building_name: building).pick(:city)
Rails 6 introduced pick method with works like where(..).pluck(..).first. Docs
I'm trying to generate a new SharePoint list item directly using SQL server. What's stopping me is damn tp_DirName column. I have no ideas how to create this value.
Just for instance, I have selected all tasks from AllUserData, and there are possible values for the column: 'MySite/Lists/Task', 'Lists/Task' and even 'MySite/Lists/List2'.
MySite is the FullUrl value from Webs table. I can obtain it. But what about 'Lists/Task' and '/Lists/List2'? Where they are stored?
If try to avoid SQL context, I can formulate it the following way: what is the object, that has such attribute as '/Lists/List2'? Where can I set it up in GUI?
Just a FYI. It is VERY not supported to try and write directly to SharePoint's SQL Tables. You should really try and write something that utilizes the SharePoint Object Model. Writing to the SharePoint database directly mean Microsoft will not support the environment.
I've discovered, that [AllDocs] table, in contrast to its title, contains information about "directories", that can be used to generate tp_DirName. At least, I've found "List2" and "Task" entries in [AllDocs].[tp_Leaf] column.
So the solution looks like this -- concatenate the following 2 components to get tp_DirName:
[Webs].[FullUrl] for the web, containing list, containing item.
[AllDocs].[tp_Leaf] for the list, containing item.
Concatenate the following 2 components to get tp_Leaf for an item:
(Item count in the list) + 1
'_.000'
Regards,
Well, my previous answer was not very useful, though it had a key to the magic. Now I have a really useful one.
Whatever they said, M$ is very liberal to the MOSS DB hackers. At least they provide the following documents:
http://msdn.microsoft.com/en-us/library/dd304112(PROT.13).aspx
http://msdn.microsoft.com/en-us/library/dd358577(v=PROT.13).aspx
Read? Then, you know that all folders are listed in the [AllDocs] table with '1' in the 'Type' column.
Now, let's look at 'tp_RootFolder' column in AllLists. It looks like a folder id, doesn't it? So, just SELECT the single row from the [AllDocs], where Id = tp_RootFolder and Type = 1. Then, concatenate DirName + LeafName, and you will know, what the 'tp_DirName' value for a newly generated item in the list should be. That looks like a solid rock solution.
Now about tp_LeafName for the new items. Before, I wrote that the answer is (Item count in the list) + 1 + '_.000', that corresponds to the following query:
DECLARE #itemscount int;
SELECT #itemscount = COUNT(*) FROM [dbo].[AllUserData] WHERE [tp_ListId] = '...my list id...';
INSERT INTO [AllUserData] (tp_LeafName, ...) VALUES(CAST(#itemscount + 1 AS NVARCHAR(255)) + '_.000', ...)
Thus, I have to say I'm not sure that it works always. For items - yes, but for docs... I'll inquire into the question. Leave a comment if you want to read a report.
Hehe, there is a stored procedure named proc_AddListItem. I was almost right. MS people do the same, but instead of (count + 1) they use just... tp_ID :)
Anyway, now I know THE SINGLE RIGHT answer: I have to call proc_AddListItem.
UPDATE: Don't forget to present the data from the [AllUserData] table as a new item in [AllDocs] (just insert id and leafname, see how SP does it itself).