Search Results

Search found 8161 results on 327 pages for 'django queries'.

Page 254/327 | < Previous Page | 250 251 252 253 254 255 256 257 258 259 260 261  | Next Page >

• Looking for a generic handler/service for mongodb and asp.net / c#

  - by JohnAgan

  I am new to MongoDB and have a perfect place in mind to use it. However, it's only worth it if I can make the queries from JavaScript and return JSON. I read another post on here of someone asking a similar question, but not specific to C#. What's the easiest way I can implement a generic service/handler in asp.net/c# that would allow me to interact with mongodb via JavaScript? I understand JavaScript can't call mongodb directly, so the next best thing is what I'm looking for.

  Read the article

• How to delete data in DB efficiently using LinQ to NHibernate (one-shot-delete)

  - by kastanf

  Hello, producing software for customers, mostly using MS SQL but some Oracle, a decision was made to plunge into Nhibernate (and C#). The task is to delete efficiently e.g. 10 000 rows from 100 000 and still stay sticked to ORM. I've tried named queries - link already, IQuery sql = s.GetNamedQuery("native-delete-car").SetString(0, "Kirsten"); sql.ExecuteUpdate(); but the best I have ever found seems to be: using (ITransaction tx = _session.BeginTransaction()) { try { string cmd = "delete from Customer where Id < GetSomeId()"; var count = _session.CreateSQLQuery(cmd).ExecuteUpdate(); ... Since it may not get into dB to get all complete rows before deleting them. My questions are: If there is a better way for this kind of delete. If there is a possibility to get the Where condition for Delete like this: Having a select statement (using LinQ to NHibernate) = which will generate appropriate SQL for DB = we get that Where condition and use it for Delete. Thanks :-)

  Read the article

• Find all clauses related to an atom

  - by Luc Touraille

  This is probably a very silly question (I just started learning Prolog a few hours ago), but is it possible to find all the clauses related to an atom? For example, assuming the following knowledge base: cat(tom). animal(X) :- cat(X). , is there a way to obtain every possible information about tom (or at least all the facts that are explicitly stated in the base)? I understand that a query like this is not possible: ?- Pred(tom). so I thought I could write a rule that would deduce the correct information: meta(Object, Predicate) :- Goal =.. [Predicate, Object], call(Goal). so that I could write queries such as ?- meta(tom, Predicate). but this does not work because arguments to call are not sufficiently instantiated. So basically my question is: is this at all possible, or is Prolog not design to provide this kind of information? And if it is not possible, why?

  Read the article

• I am not able to drop foreign key in mysql Error 150. Please help

  - by Shantanu Gupta

  i am trying to create a foreign key in my table. But when i executes my query it shows me error 150 Error Code : 1005 Can't create table '.\vts#sql-6ec_1.frm' (errno: 150) (0 ms taken) My Queries are Query to create a foreign Key alter table `vts`.`tblguardian` add constraint `FK_tblguardian` FOREIGN KEY (`GuardianPickPointId`) REFERENCES `tblpickpoint` (`PickPointId`) EDIT: Now I am trying to drop this constraint But it fails again and shows me same error as it was giving when i was trying to create foreign key. alter table `vts`.`tblguardian` drop index `FK_tblguardian` Primary Key table CREATE TABLE `tblpickpoint` ( `PickPointId` int(4) NOT NULL auto_increment, `PickPointName` varchar(500) default NULL, `PickPointLabel` varchar(500) default NULL, `PickPointLatLong` varchar(100) NOT NULL, PRIMARY KEY (`PickPointId`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 CHECKSUM=1 DELAY_KEY_WRITE=1 ROW_FORMAT=DYNAMIC Foreign Key Table CREATE TABLE `tblguardian` ( `GuardianId` int(4) NOT NULL auto_increment, `GuardianName` varchar(500) default NULL, `GuardianAddress` varchar(500) default NULL, `GuardianMobilePrimary` varchar(15) NOT NULL, `GuardianMobileSecondary` varchar(15) default NULL, `GuardianPickPointId` int(4) default NULL, PRIMARY KEY (`GuardianId`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1

  Read the article

• StackExchange API key

  - by user21289

  I am working on a project with the StackExchange API, the problem is at a moment I have this Exception on eclipse console: java.io.IOException: Server returned HTTP response code: 400 for URL: https://api.stackexchange.com/2.1/questions?order=desc&sort=votes&tagged=OSM&site=stackoverflow at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(Unknown Source) atbr.inf.pucrio.sog.StackOverflowAcessor.getQuestionsIds(StackOverflowAcessor.java:41) After verifying on the browser with the same link, I have this error message: {"error_id":502,"error_name":"throttle_violation","error_message":"too many requests from this IP, more requests available in 74089 seconds"} I am wondering if this is dur to the limited numbers of the queries per day, if it is the case, how can I do to have the key? if it is not, how can I do to resolve the problem?

  Read the article

• How can I enable MySQL's slow query log without restarting MySQL?

  - by mmattax

  I followed the instructions here: http://crazytoon.com/2007/07/23/mysql-changing-runtime-variables-with-out-restarting-mysql-server/ but that seems to only set the threshold. Do I need to do anything else like set the filepath? According to MySQL's docs If no file_name value is given for --log-slow-queries, the default name is host_name-slow.log. The server creates the file in the data directory unless an absolute path name is given to specify a different directory. Running SHOW VARIABLES doesn't indicate any log file path and I don't see any slow query log file on my server...

  Read the article

• nth smallest number among two databases of size n each using divide and conquer

  - by urfriend

  we have two databases of size n containing numbers without repeats. So, in total we have 2n elements. They can be accessed through a query to one database at a time. The query is such that you give it a k and it returns kth smallest entry in that database. we need to find nth smallest entry among all the 2n elements in O(logn) queries. the idea is to use divide and conquer but i need some help thinking through this. thanks!

  Read the article

• search engine crawling frequency

  - by Aditya Pratap Singh

  I want to design a search engine for news websites ie. download various article pages from these websites, index the pages, and answer search queries on the index. I want a short pseudocode to find an appropriate crawling frequency -- i do not want to crawl too often because the website may not have changed, and do not want to crawl too infrequently because index would then be out of date. Assume that crawling code looks as follows while(1) { sleep(sleep_interval); // sleep for sleep_interval crawl(website); // crawls the entire website diff = diff(currently_crawled_website, previously_crawled_website); // returns a % value of difference between the latest and previous crawls of the website sleep_interval = infer_sleep_interval(diff, sleep_interval); } looking for a pseudocode for the infer_sleep_interval method: long sleep_interval infer_sleep_interval(int diff_percentage,long previous_sleep_interval) { ... ... ... } i want to design method which adaptively alters the sleeping interval based on the update frequency of the website.

  Read the article

• comparing two cursors in oracle instead of using MINUS

  - by Omnipresent

  The following query takes more than 3 minutes to run because tables contain massive amounts of data: SELECT RTRIM(LTRIM(A.HEAD)), A.EFFECTIVE_DATE, FROM TABLE_1 A WHERE A.TYPE_OF_ACTION='6' AND A.EFFECTIVE_DATE >= ADD_MONTHS(SYSDATE,-15) MINUS SELECT RTRIM(LTRIM(B.head)), B.EFFECTIVE_DATE, FROM TABLE_2 B In our system a query gets killed if it is running for more than 8 seconds. Is there a way to run the queries individually ..put them in cursors..compare and then get the results? that way each query will be ran individually rather than as one massive query which takes 3 minutes. How would two cursors be compared to mimic the MINUS?

  Read the article

• Ruby ways to authenticate using headers?

  - by webdestroya

  I am designing an API system in Ruby-on-Rails, and I want to be able to log queries and authenticate users. However, I do not have a traditional login system, I want to use an APIkey and a signature that users can submit in the HTTP headers in the request. (Similar to how Amazon's services work) Instead of requesting /users/12345/photos/create I want to be able to request /photos/create and submit a header that says X-APIKey: 12345 and then validate the request with a signature. Are there any gems that can be adapted to do that? Or better yet, any gems that do this without adaptation? Or do you feel that it would be wiser to just have them send the API key in each request using the POST/GET vars?

  Read the article

• Mysqld Crashes immediately on running on Windows 7...?

  - by Cyril Gupta

  I am trying to run MySql 5.1 on Windows 7 Home Premium 64 bit. I have downloaded the MSI installer from the MYSql website and installed it. The installation is successful, but the service does not start. If I try to run MySql manually using the mysqld executable, it crashes immediately on running (error: mysqld.exe has stopped working). Earlier mysql was running on the machine, but I had some problem with it (wasn't executing big queries) and installed it again which somehow broke the program. I had installed it to work as a service which started giving me this isse, and now it won't work even if I don't install it as a service. I have tried removing the mysql folder and re-installing. Is there somewhere else where Mysql saves configuration info or other data? Has anyone else found this problem and solved it? How can I find out why the process is failing to run?

  Read the article

• Resources to learn about engineering aspects of data analytics (OLAP, warehousing, ETL, etc.)

  - by JT

  I'm a math/stats guy, interested in learning more about the engineering aspects of "data analytics" (this may be an overly broad term, this is a case of "I don't know what I don't know", so I'm not sure how to be more specific). I'm fine with manipulating and analyzing the data once it's already stored somewhere and I can access it, and I'm fine with writing scripts and SQL queries (and have a general knowledge of things like normalization). What I don't know is the whole engineering process of capturing and storing the data. For example, terms I've heard thrown about that I only vaguely understand the meaning of include: - OLAP, OLTP - Data warehousing - ETL - ??? What's a good book (or any other resource) to learn about these kinds of things? What are things I should know about database design (normalization seems kinda "obvious" to me, something I would have done even before I knew the term -- is there anything else?)? In other words, for jobs falling under the umbrella term of "analytics engineer", what kinds of things should I know?

  Read the article

• Freebase Query with "JOINS"

  - by codemonkey

  ... Yeah, yeah, I know traditional joins don't exist. I actually like the freebase query methodology in theory, just having a little trouble getting it to actually work for me : ) Anyone have a dumb-simple example of getting Freebase data via MQL that pulls from two different "tables"? In particular, I'm trying to get automotive data... so for example, pulling fields from both /automotive/model_year and /automotive/trim_year. I've read the documentation (for hours actually). There's a distinct possibility that I'm looking right at such an example somewhere and just not seeing it because my OLTP brain just doesn't comprehend what it's seeing. * Note * ... that the two "types" I'm working with above are siblings, not parent/child. Does freebase even allow joining data between sibling nodes... I see examples of queries pulling from parent/child, but not from siblings I don't think (or I've overlooked them).

  Read the article

• Can Entity Framework be used for the purpose of entity/schema definition at application runtime?

  - by Kabeer

  Hello. Can 'Entity Framework' be used for the purpose of entity definition at application runtime? Ok, to make it simple, here is what I want to achieve: My application is a product. I should be able to define entities at runtime on the basis of inputs gathered from an 'authoring' user (in effect this means 'model first' approach). These entities are of course persistable. Further, after having defined the entities and their relationships, I should be able to make complex queries across them for many reasons, including reports. Is the above possible and how? So far what I have realized is that there is a dependency on Visual Studio.

  Read the article

• HSM - cryptoki - opening sessions overhead

  - by Raj

  I am having a query regarding sessions with HSM. I am aware that there is an overhead if you initialise and finalise the cryptoki api for every file you want to encrypt/decrypt. My queries are, Is there an overhead in opening and closing individual sessions for every file, you want to encrypt/decrypt.(C_Initialize/C_Finalize) How many maximum number of sessions can i have for a HSM simultaneously, with out affecting the performance? Is opening and closing the session for processing individual files the best approach or opening a session and processing multiple files and then closing the session the best approach? Thanks

  Read the article

• What are the pros and cons to keeping SQL in Stored Procs versus Code

  - by Guy

  What are the advantages/disadvantages of keeping SQL in your C# source code or in Stored Procs? I've been discussing this with a friend on an open source project that we're working on (C# ASP.NET Forum). At the moment, most of the database access is done by building the SQL inline in C# and calling to the SQL Server DB. So I'm trying to establish which, for this particular project, would be best. So far I have: Advantages for in Code: Easier to maintain - don't need to run a SQL script to update queries Easier to port to another DB - no procs to port Advantages for Stored Procs: Performance Security

  Read the article

• PDO update query with conditional?

  - by dmontain

  I have a PDO mysql that updates 3 fields. $update = $mypdo->prepare("UPDATE tablename SET field1=:field1, field2=:field2, field3=:field3 WHERE key=:key"); But I want field3 to be updated only when $update3 = true; (meaning that the update of field3 is controlled by a conditional statement) Is this possible to accomplish with a single query? I could do it with 2 queries where I update field1 and field2 then check the boolean and update field3 if needed in a separate query. //run this query to update only fields 1 and 2 $update_part1 = $mypdo->prepare("UPDATE tablename SET field1=:field1, field2=:field2 WHERE key=:key"); //if field3 should be update, run a separate query to update it separately if ($update3){ $update_part2 = $mypdo->prepare("UPDATE tablename SET field3=:field3 WHERE key=:key"); } But hopefully there is a way to accomplish this in 1 query?

  Read the article

• 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

  Read the article

• Linq to SQL gives NotSupportedException when using local variables

  - by zwanz0r

  It appears to me that it matters whether you use a variable to temporary store an IQueryable or not. See the simplified example below: This works: List<string> jobNames = new List<string> { "ICT" }; var ictPeops = from p in dataContext.Persons where ( from j in dataContext.Jobs where jobNames.Contains(j.Name) select j.ID).Contains(p.JobID) select p; But when I use a variable to temporary store the subquery I get an exception: List<string> jobNames = new List<string> { "ICT" }; var jobs = from j in dataContext.Jobs where jobNames.Contains(j.Name) select j.ID; var ictPeops = from p in dataContext.Persons where jobs.Contains(p.JobID) select p; "System.NotSupportedException: Queries with local collections are not supported" I don't see what the problem is. Isn't this logic that is supposed to work in LINQ?

  Read the article

• Retrieve names by ratio of their occurance

  - by jjiffer

  Hello, I'm somewhat new to SQL queries, and I'm struggling with this particular problem. Let's say I have query that returns the following 3 records (kept to one column for simplicity): Tom Jack Tom And I want to have those results grouped by the name and also include the fraction (ratio) of the occurrence of that name out of the total records returned. So, the desired result would be (as two columns): Tom | 2/3 Jack | 1/3 How would I go about it? Determining the numerator is pretty easy (I can just use COUNT() and GROUP BY name), but I'm having trouble translating that into a ratio out of the total rows returned. Any help is much appreciated!

  Read the article

• Catching constraint violations in JPA 2.0.

  - by Dennetik

  Consider the following entity class, used with, for example, EclipseLink 2.0.2 - where the link attribute is not the primary key, but unique nontheless. @Entity public class Profile { @Id private Long id; @Column(unique = true) private String link; // Some more attributes and getter and setter methods } When I insert records with a duplicate value for the link attribute, EclipseLink does not throw a EntityExistsException, but throws a DatabaseException, with the message explaining that the unique constraint was violated. This doesn't seem very usefull, as there would not be a simple, database independent, way to catch this exception. What would be the advised way to deal with this? A few things that I have considered are: Checking the error code on the DatabaseException - I fear that this error code, though, is the native error code for the database; Checking the existence of a Profile with the specific value for link beforehand - this obviously would result in an enormous amount of superfluous queries.

  Read the article

• Safe HttpContext.Current.Cache Usage

  - by Burak SARICA

  Hello there, I use Cache in a web service method like this : var pblDataList = (List<blabla>)HttpContext.Current.Cache.Get("pblDataList"); if (pblDataList == null) { var PBLData = dc.ExecuteQuery<blabla>( @"SELECT blabla"); pblDataList = PBLData.ToList(); HttpContext.Current.Cache.Add("pblDataList", pblDataList, null, DateTime.Now.Add(new TimeSpan(0, 0, 15)), Cache.NoSlidingExpiration, CacheItemPriority.Normal, null); } I wonder is it thread safe? I mean the method is called by multiple requesters And more then one requester may hit the second line at the same time while the cache is empty. So all of these requesters will retrieve the data and add to cache. The query takes 5-8 seconds. May a surrounding lock statement around this code prevent that action? (I know multiple queries will not cause error but i want to be sure running just one query.)

  Read the article

• Oracle - Is there any effects of not having a primary key on a table ?

  - by Sathya

  We use sequence numbers for primary keys on the tables. There are some tables where we dont really use the primary key for any querying purpose. But, we have Indexes on other columns. These are non-unique indexes. The queries use these non-primary key columns in the WHERE conditions. So, I dont really see any benefit of having a primary key on such tables. My experience with SQL 2000 was that, it used to replicate tables which had some primary key. Otherwise it would not. I am using Oracle 10gR2. I would like to know if there are any such side-effects of having tables that dont have primary key.

  Read the article

• Recursive query question - break rows into columns?

  - by Stew

  I have a table "Families", like so FamilyID PersonID Relationship ----------------------------------------------- F001 P001 Son F001 P002 Daughter F001 P003 Father F001 P004 Mother F002 P005 Daughter F002 P006 Mother F003 P007 Son F003 P008 Mother and I need output like FamilyID PersonID Father Mother ------------------------------------------------- F001 P001 P003 P004 F001 P002 P003 P004 F001 P003 F001 P004 F002 P005 P006 F002 P006 F003 P007 P008 F003 P008 In which the PersonID of the Father and Mother for a given PersonID are listed (if applicable) in separate columns. I know this must be a relatively trivial query to write (and therefore to find instructions for), but I can't seem to come up with the right search terms. Searching "SQL recursive queries" has gotten me closest, but I can't quite translate those methods to what I'm trying to do here. I'm trying to learn, so multiple methods are welcome, as is vocabulary I should read up on. Thanks!

  Read the article

• "Access is denied" error on accessing iframe document object

  - by Ovesh

  For posting AJAX forms in a form with many parameters, I am using a solution of creating an iframe, posting the form to it by POST, and then accessing the iframe's content. specifically, I am accessing the content like this: $("some_iframe_id").get(0).contentWindow.document I tested it and it worked. On some of the pages, I started getting an "Access is denied" error. As far as I know, this shouldn't happen if the iframe is served from the same domain. I'm pretty sure it was working before. Anybody have a clue? If I'm not being clear enough: I'm posting to the same domain. So this is not a cross-domain request. I am testing on IE only. P.S. I can't use simple ajax POST queries (don't ask...)

  Read the article

< Previous Page | 250 251 252 253 254 255 256 257 258 259 260 261  | Next Page >