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  • Linq query with subquery as comma-separated values

    - by Keith
    In my application, a company can have many employees and each employee may have have multiple email addresses. The database schema relates the tables like this: Company - CompanyEmployeeXref - Employee - EmployeeAddressXref - Email I am using Entity Framework and I want to create a LINQ query that returns the name of the company and a comma-separated list of it's employee's email addresses. Here is the query I am attempting: from c in Company join ex in CompanyEmployeeXref on c.Id equals ex.CompanyId join e in Employee on ex.EmployeeId equals e.Id join ax in EmployeeAddressXref on e.Id equals ax.EmployeeId join a in Address on ax.AddressId equals a.Id select new { c.Name, a.Email.Aggregate(x=x + ",") } Desired Output: "Company1", "[email protected],[email protected],[email protected]" "Company2", "[email protected],[email protected],[email protected]" ... I know this code is wrong, I think I'm missing a group by, but it illustrates the point. I'm not sure of the syntax. Is this even possible? Thanks for any help.

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  • Best solution for reporting database

    - by zzyzx
    Here is the situation: There is a transaction intensive database - used for both routine transactions and reports. I was wondering if I could isolate these two operations and 2 independent databases, so reports could run off of one database and all the transactions could occur in another one. This would improve performance for the OLTP SQL database. I have gone over a few options like, Mirroring, Log shipping, Replication, Snapshots, Clustering - but would like to discuss the best possible strategy for the desired result. Please advise the best solution to implement this strategy, or any other thoughts/suggestion you may have.

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  • How to use correctly the Query Window in SQL Server 2008

    - by Richard77
    Hello, What should I do to avoid that commands be executed each time I hit 'Execute !. icon' I mean this USE master; GO CREATE DATABASE Sales GO USE Sales; GO CREATE TABLE Customers( CustomerID int NOT NULL, LName varchar (50) NOT NULL, FName varchar (50) NULL, Status varchar (10), ModifiedBy varchar (30) NULL ) GO When I click Execute!, Sql Server tries to redo the same thing. What I do for now is to delete the Query Window completely then write what I need before clicking the Execute icon. But, I doubt that I should be doing that. What can I do to keep writing the commands without having each time to clear the Query Window? Thanks for helping

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  • Page zoom slows down page rendering

    - by Alex
    I'm building a map viewer much like Google maps and i've run into an interesting performance problem when a page is zoomed (i.e ctrl + OR ctrl -). It seems to affect all major browsers but Firefox has the worst problems as far as I can tell. The problem is that when the page is zoomed panning by dragging the mouse seems really sluggish. This can even be seen on Google maps. Pan the map left and right and note how smooth it is. Now press ctrl+ (3 or 4 times). Now pan the map left and right in the same way. Notice the difference? Does anyone know how I can minimize this problem?

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  • Join Query Help

    - by John
    Hello, The query below works well. It pulls data from two MySQL tables, "submission" and "login." I would like to also pull data from a third table called "comment" in the same database. The table "comment" has the following fields: commentid, loginid, submissionid, comment, datecommented Two of the fields in the table "login" are called "loginid" and "username." In the query below, I would like to count all "commentid" in "comment" where "loginid" equals the "loginid" in "login" where "username" equals "$profile." How can I do this? Thanks in advance, John $sqlStr1 = "SELECT l.username, l.loginid, s.loginid, s.submissionid, s.title, s.url, s.datesubmitted, s.displayurl, l.created, count(s.submissionid) countSubmissions FROM submission AS s INNER JOIN login AS l ON s.loginid = l.loginid WHERE l.username = '$profile'";

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  • Must .aspx files have a page directive?

    - by Keith Bloom
    Around 90% of the pages for our websites have no .Net code embedded in them yet are published as .aspx files. I want these to render as fast as possible so I'm removing as much as I can. Does the .Net page directive have an impact on performance? I am thinking about two factors; the page speed for each GET and what happens when the file changes. The CMS system re-creates each page daily and I'm wondering if this triggers the ASP.Net compilation process.

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  • How to populate an array with recordset data

    - by Curtis Inderwiesche
    I am attempting to move data from a recordset directly into an array. I know this is possible, but specifically I want to do this in VBA as this is being done in MS Access 2003. Typically I would do something like the following to archive this: Dim vaData As Variant Dim rst As ADODB.Recordset ' Pull data into recordset code here... ' Populate the array with the whole recordset. vaData = rst.GetRows What differences exist between VB and VBA which makes this type of operation not work? What about performance concerns? Is this an "expensive" operations?

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  • username and password check linq query in c#

    - by b0x0rz
    this linq query var users = from u in context.Users where u.UserEMailAdresses.Any(e1 => e1.EMailAddress == userEMail) && u.UserPasswords.Any(e2 => e2.PasswordSaltedHash == passwordSaltedHash) select u; return users.Count(); returns: 1 even when there is nothing in password table. how come? what i am trying to do is get the values of email and passwordHash from two separate tables (UserEMailAddresses and UserPasswords) linked via foreign keys to the third table (Users). it should be simple - checking if email and password mach from form to database. but it is not working for me. i get 1 (for count) even when there are NO entries in the UserPasswords table. is the linq query above completely wrong, or...?

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  • SQL Server 2005 - query with case statement

    - by user329266
    Trying to put a single query together to be used eventually in a SQL Server 2005 report. I need to: Pull in all distinct records for values in the "eventid" column for a time frame - this seems to work. For each eventid referenced above, I need to search for all instances of the same eventid to see if there is another record with TaskName like 'review1%'. Again, this seems to work. This is where things get complicated: For each record where TaskName is like review1, I need to see if another record exists with the same eventid and where TaskName='End'. Utimately, I need a count of how many records have TaskName like 'review1%', and then how many have TaskName like 'review1%' AND TaskName='End'. I would think this could be accomplished by setting a new value for each record, and for the eventid, if a record exists with TaskName='End', set to 1, and if not, set to 0. The query below seems to accomplish item #1 above: SELECT eventid, TimeStamp, TaskName, filepath FROM (SELECT eventid, TimeStamp, filepath, TaskName, ROW_NUMBER() OVER(PARTITION BY eventid ORDER BY TimeStamp DESC) AS seq FROM eventrecords where ((TimeStamp >= '2010-4-1 00:00:00.000') and (TimeStamp <= '2010-4-21 00:00:00.000'))) AS T WHERE seq = 1 order by eventid And the query below seems to accomplish #2: SELECT eventid, TimeStamp, TaskName, filepath FROM (SELECT eventid, TimeStamp, filepath, TaskName, ROW_NUMBER() OVER(PARTITION BY eventid ORDER BY TimeStamp DESC) AS seq FROM eventrecords where ((TimeStamp >= '2010-4-1 00:00:00.000') and (TimeStamp <= '2010-4-21 00:00:00.000')) and TaskName like 'Review1%') AS T WHERE seq = 1 order by eventid This will bring back the eventid's that also have a TaskName='End': SELECT eventid, TimeStamp, TaskName, filepath FROM (SELECT eventid, TimeStamp, filepath, TaskName, ROW_NUMBER() OVER(PARTITION BY eventid ORDER BY TimeStamp DESC) AS seq FROM eventrecords where ((TimeStamp >= '2010-4-1 00:00:00.000') and (TimeStamp <= '2010-4-21 00:00:00.000')) and TaskName like 'Review1%') AS T WHERE seq = 1 and eventid in (Select eventid from eventrecords where TaskName = 'End') order by eventid So I've tried the following to TRY to accomplish #3: SELECT eventid, TimeStamp, TaskName, filepath FROM (SELECT eventid, TimeStamp, filepath, TaskName, ROW_NUMBER() OVER(PARTITION BY eventid ORDER BY TimeStamp DESC) AS seq FROM eventrecords where ((TimeStamp >= '2010-4-1 00:00:00.000') and (TimeStamp <= '2010-4-21 00:00:00.000')) and TaskName like 'Review1%') AS T WHERE seq = 1 and case when (eventid in (Select eventid from eventrecords where TaskName = 'End') then 1 else 0) as bit end order by eventid When I try to run this, I get: "Incorrect syntax near the keyword 'then'." Not sure what I'm doing wrong. Haven't seen any examples anywhere quite like this. I should mention that eventrecords has a primary key, but it doesn't seem to help anything when I include it, and I am not permitted to change the table. (ugh) I've received one suggestion to use a cursor and temporary table, but am not sure how badley that would bog down performance when the report is running. Thanks in advance.

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  • How to Expression.Invoke an arbitrary LINQ 2 SQL Query

    - by Remus Rusanu
    Say I take an arbitrary LINQ2SQL query's Expression, is it possible to invoke it somehow? MyContext ctx1 = new MyContext("..."); var q = from t in ctx1.table1 where t.id = 1 select t; Expression qe = q.Expression; var res = Expression.Invoke(qe); This throws ArgumentException "Expression of type System.Linq.IQueryable`1[...]' cannot be invoked". My ultimate goal is to evaluate the same query on several different data contexts.

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  • Query Only Specified Number Of Items From Parent/Child Categories

    - by RogeR
    I'm having trouble figureing out how to query every item in a certain category and only list the newest 10 items by date. Here is my table layout: download_categories category_id (int) primary key title (var_char) parent_id (int) downloads id (int) primary key title (var_char) category_id (int) date (date) I need to query every file in a main category that lets say has 100 items and 5 child categories and only spit out the last 10 added. I have functions right now that just add up all the files so I can get a count by category, but I can't seem to modify the code to only display a certain amount of items based on the date.

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  • MySQL: Storage of multiple text fields for a record

    - by Tom
    An inexperienced question: I need to store about 10 unknown-length text fields per record into a MySQL table. I expect no more than 50K rows in total for this table but speed is important. The database actions will be solely SELECTs for all practical purposes. I'm using InnoDB. In other words: id | text1 | text2 | text3 | .... | text10 As I understand that MySQL will store the text elsewhere and use its own indicators on the table itself, I'm wondering whether there's any fundamental performance implications that I should be worrying about given the way the data is stored? (i.e. several "sub-fetches" from the table). Thank you.

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  • Python threads all executing on a single core

    - by Rob Lourens
    I have a Python program that spawns many threads, runs 4 at a time, and each performs an expensive operation. Pseudocode: for object in list: t = Thread(target=process, args=(object)) # if fewer than 4 threads are currently running, t.start(). Otherwise, add t to queue But when the program is run, Activity Monitor in OS X shows that 1 of the 4 logical cores is at 100% and the others are at nearly 0. Obviously I can't force the OS to do anything but I've never had to pay attention to performance in multi-threaded code like this before so I was wondering if I'm just missing or misunderstanding something. Thanks.

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  • Windows Azure Table Storage LINQ Operators

    - by Ryan Elkins
    Currently Table Storage supports From, Where, Take, and First. Are there plans to support any of the other 29 operators? If we have to code for these ourselves, how much of a performance difference are we looking at to something similar via SQL and SQL Server? Do you see it being somewhat comparable or will it be far far slower if I need to do a Count or Sum or Group By over a gigantic dataset? I like the Azure platform and the idea of cloud based storage. I like Windows Azure for the amount of data it can store and the schema-less nature of table storage. SQL Azure just won't work due to the high cost to storage space.

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  • sql query question

    - by bu0489
    hey guys, just having a bit of difficulty with a query, i'm trying to figure out how to show the most popular naturopath that has been visited in a centre. My tables look as follows; Patient(patientId, name, gender, DoB, address, state,postcode, homePhone, businessPhone, maritalStatus, occupation, duration,unit, race, registrationDate , GPNo, NaturopathNo) and Naturopath (NaturopathNo, name, contactNo, officeStartTime, officeEndTime, emailAddress) now to query this i've come up with SELECT count(*), naturopathno FROM dbf10.patient WHERE naturopathno != 'NULL' GROUP BY naturopathno; which results in; COUNT(*) NATUROPATH 2 NP5 1 NP6 3 NP2 1 NP1 2 NP3 1 NP7 2 NP8 My question is, how would I go about selecting the highest count from this list, and printing that value with the naturopaths name? Any suggestions are very welcome, Brad

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  • ms-access: DB engine cannot find input table or query

    - by every_answer_gets_a_point
    here's the query: SELECT * FROM (SELECT [Occurrence Number], [Occurrence Date], [1 0 Preanalytical (Before Testing)], [Cup Type], NULL as [2 0 Analytical (Testing Phase)], [2 0 Area], NULL as [3 0 Postanalytical ( After Testing)],NULL as [4 0 Other], [Practice Code], [Specimen ID #] FROM [Lab Occurrence Form] WHERE NOT ([1 0 Preanalytical (Before Testing)] IS NULL) UNION SELECT [Occurrence Number], [Occurrence Date],NULL, [Cup Type],[2 0 Analytical (Testing Phase)], [2 0 Area], NULL,NULL, [Practice Code], [Specimen ID #] FROM [Lab Occurrence Form] WHERE NOT ([2 0 Analytical (Testing Phase)] IS NULL) UNION SELECT [Occurrence Number], [Occurrence Date],NULL, [Cup Type],NULL, [2 0 Area], [3 0 Postanalytical ( After Testing)],NULL, [Practice Code], [Specimen ID #] FROM [Lab Occurrence Form] WHERE NOT ([3 0 Postanalytical ( After Testing)] IS NULL) UNION SELECT [Occurrence Number], [Occurrence Date],NULL, [Cup Type],NULL, [2 0 Area], NULL, [4 0 Other] FROM [Lab Occurrence Form], [Practice Code], [Specimen ID #] WHERE NOT ([4 0 Other] IS NULL) ) AS mySubQuery ORDER BY mySubQuery.[Occurrence Number]; for some reason it doesnt like [Practice Code]. it's definitely a column in the table so i dont understand the problem. the error is the microsoft office access database engine cannot find the input table or query 'Practice Code'........

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  • SELECT INTO or Stored Procedure?

    - by Kerry
    Would this be better as a stored procedure or leave it as is? INSERT INTO `user_permissions` ( `user_id`, `object_id`, `type`, `view`, `add`, `edit`, `delete`, `admin`, `updated_by_user_id` ) SELECT `user_id`, $object_id, '$type', 1, 1, 1, 1, 1, $user_id FROM `user_permissions` WHERE `object_id` = $object_id_2 AND `type` = '$type_2' AND `admin` = 1 You can think of this with different objects, lets say you have groups and subgroups. If someone creates a subgroup, it is making everyone who had access to the parent group now also have access to the subgroup. I've never made a stored procedure before, but this looks like it might be time. This call be probably be called very often. Should I be creating a procedure or will the performance be insignificant?

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  • How does mysql define DISTINCT()

    - by goran
    AFAIK SQL defines two uses of DISTINCT keywords - SELECT DISTINCT field... and SELECT COUNT(DISTINCT field) ... However in one of web applications that I administer I've noticed performance issues on queries like SELECT DISTINCT(field1), field2, field3 ... DISTINCT() on a single column makes no sense and I am almost sure it is interpreted as SELECT DISTINCT field1, field2, field3 ... but how can I prove this? I've searched mysql site for a reference on this particular syntax but could not find any. Does anyone have a link to definition of DISTINCT() in mysql or knows about other authoritative source on this? Best

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  • question on database query using hibernate in java with annotations

    - by molleman
    Hello, simple question regarding HQL(Hibernate query language) so i have user class , that can hold a list of Projects, how do i take this out of the database depending on a username, this is how i take out my user String username = "stephen"; YFUser user = (YFUser) session.createQuery("select u FROM YFUser u where u.username = :username").setParameter("username", name).uniqueResult(); but i want to take out the list of projects here is the projects list within the class YFUser(my user class); how would i query the database to get this list of projects @Entity @Table(name = "yf_user_table") public class YFUser implements Serializable,ILightEntity { ......... @OneToMany(cascade = CascadeType.ALL,fetch = FetchType.LAZY) @JoinTable(name = "YFUSER_JOIN_PROJECT", joinColumns = { @JoinColumn(name = "user_id") }, inverseJoinColumns = { @JoinColumn(name = "project_id") }) private List<Project> projects = new ArrayList<Project>();

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  • Speeding up inner joins between a large table and a small table

    - by Zaid
    This may be a silly question, but it may shed some light on how joins work internally. Let's say I have a large table L and a small table S (100K rows vs. 100 rows). Would there be any difference in terms of speed between the following two options?: OPTION 1: OPTION 2: --------- --------- SELECT * SELECT * FROM L INNER JOIN S FROM S INNER JOIN L ON L.id = S.id; ON L.id = S.id; Notice that the only difference is the order in which the tables are joined. I realize performance may vary between different SQL languages. If so, how would MySQL compare to Access?

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  • Query DNSBL or other block lists using PHP

    - by 55skidoo
    Is there any way to use PHP code to query a DNSBL (block list) provider and find out if the IP address submitted is a bad actor? I would like to take an existing IP address out of a registration database, then check whether it's a known block-listed IP address by performing a lookup on it, then if it's a blacklisted, do an action on it (such as, delete entry from registration database). Most of the instructions I have seen assume you are trying to query the blocklist via a mail server, which I can't do. I tried querying via web browser by typing in queries such as "58.64.xx.xxx.dnsbl.sorbs.net" but that didn't work.

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  • Soql query to get all related contacts of an account in an opportunity

    - by Prady
    i have SOQL query which queries for some records based on a where condition. select id, name,account.name ... <other fields> from opportunity where eventname__c='Test Event' i also need to get the related contact details for the account in the opportunity. ie i need to add the email ids of contact who all are part of the account in the opportunity. For each opportunity, i need to get all the contacts emailids who are associated with the account in opportunity. I cant really figure out how to approach this. referring the documentation i can get the contact info of a account using the query SELECT Name, ( SELECT LastName FROM Contacts ) FROM Account How can i use this along with opportunity? Thanks

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  • Datastore query outputting for Django form instance

    - by Jelle
    Hello! I'm using google appengine and Django. I'm using de djangoforms module and wanted to specify the form instance with the information that comes from the query below. userquery = db.GqlQuery("SELECT * FROM User WHERE googleaccount = :1", users.get_current_user()) form = forms.AccountForm(data=request.POST or None,instance=?????) I've found a snippet in a sample app that does this trick, but I can't modify it to work with the query I need. gift = User.get(db.Key.from_path(User.kind(), int(gift_id))) if gift is None: return http.HttpResponseNotFound('No gift exists with that key (%r)' % gift_id) form = RegisterForm(data=request.POST or None, instance=gift) Could anyone help me?

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  • Strange profiling results: definitely non-bottleneck method pops up

    - by jkff
    I'm profiling a program using sampling profiling in YourKit and JProfiler, and also "manually" (I launch it and press Ctrl-Break several times to get thread dumps). All three methods give me extremely strange results: some tens of percents of time spent in a 3-line method that does not even do any allocation or synchronization and doesn't have loops etc. Moreover, after I made this method into a NOP and even removed its invocation completely, the observable program performance didn't change at all (although it got a negligible memory leak, since it was a method for freeing a cheap resource). I'm thinking that this might be because of the constraints that JVM puts on the moments at which a thread's stacktrace may be taken, and it somehow turns out that in my program it is exactly the moments where this method is invoked, although there is absolutely nothing special about it or the context in which it is invoked. What can be the explanation for this phenomenon? What are the aforementioned constraints? What further measurements can I take to clarify the situation?

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