Search Results

Search found 33242 results on 1330 pages for 'database optimization'.

Page 679/1330 | < Previous Page | 675 676 677 678 679 680 681 682 683 684 685 686  | Next Page >

• Creating a triple store query using SQL - how to find all triples that have a common predicate and o

  - by Ankur

  I have a database that acts like a triple store, except that it is just a simple MySQL database. I want to select all triples that have a common predicate and object. Info about RDF and triples I can't seem to work out the SQL. If I had just a single predicate and object to match I would do: select TRIPLE from TRIPLES where PREDICATE="predicateName" and OBJECT="objectName" But if I have a list (HashMap) of many pairs of (predicateName,objectName) I am not sure what I need to do. Please let me know if I need to provide more info, I am not sure that I have made this quite clear, but I am wary of providing too much info and confusing the issue.

  Read the article

• Using a ICollection Value in sqlite SELECT parameterized statment

  - by case23

  Im trying to get all the entrys from a sqlite Database which have the same name as the keys in a Hashtable. My Statement looks like this. // the keys from the hashtable are names equivalent // to name entrys in the SomeTable Names Collumn Hashtable names; String query = "SELECT Id, Name FROM SomeTable WHERE Name LIKE (@Names)"; SQLiteCommand command = new SQLiteCommand(query, _databaseConnection); command.Parameters.AddWithValue("@Names", names.Keys); SQLiteDataReader reader = reader.ExecuteReader(); while(reader.Read()) { Console.WriteLine("Name: {0}, ID: {1}", reader[1].ToString(), reader[0].ToString()); } Im totally sure there are similar values in the Database, but i get nothing back and the reader does not execute. Is it impossible to add a ICollection as a Parameter Value so i need to start the reader only one time?

  Read the article

• Why should I reuse XmlHttpRequest objects?

  - by Xavi

  From what I understand, it's a best practice to reuse XmlHttpRequest objects whenever possible. Unfortunately, I'm having a hard time understanding why. It seems like trying to reuse XHR objects can increase code complexity, introduce possible browser incompatibilities, and lead to other subtle bugs. After researching this question for a while, I did come up with a list of possible explanations: Fewer objects created means less garbage collecting Reusing XHR objects reduces the chance of memory leaks The overhead of creating a new XHR object is high The browser is able to perform some sort of network optimization under hood But I'm not sure if any of these reasons are actually valid. Any light you can shed on this question would be much appreciated.

  Read the article

• Concatenating databases with Squeryl

  - by Pengin

  I'm trying to use Squeryl to take the contents of a table from one database, and append it to the equivalent table in another database. The primary key will have to be reassigned in the process, but I'm getting the error NULL not allowed for column "SIMID". Why is this? object Concatenator { def main(args: Array[String]) { Class.forName("org.h2.Driver"); val seshA = Session.create( java.sql.DriverManager.getConnection("jdbc:h2:file:data/resultsA", "sa", "password"), new H2Adapter ) val seshB = Session.create( java.sql.DriverManager.getConnection("jdbc:h2:file:data/resultsB", "sa", "password"), new H2Adapter ) using(seshA){ import Library._ from(sims){s => select(s)}.foreach{item => using(seshB){ sims.insert(item); } } } } case class Simulation( @Column("SIMID") var id: Long, val date: Date ) extends KeyedEntity[Long] object Library extends Schema { val sims = table[Simulation] on(sims)(s => declare( s.id is(unique, indexed, autoIncremented) )) } }

  Read the article

• Can Goldberg algorithm in ocamlgraph be used to find Minimum Cost Flow graph?

  - by Tautrimas

  I'm looking for an implementation to the Minimum Cost Flow graph problem in OCaml. OCaml library ocamlgraph has Goldberg algorithm implementation. The paper called Efficient implementation of the Goldberg-Tarjan minimum-cost flow algorithm is noting that Goldberg-Tarjan algorithm can find minimum cost graph. Question is, does ocamlgraph algorithm also find the minimum cost? Library documentation only states, that it's suitable at least for the maximum flow problem. If not, does anybody have a good link to a nice any minimum cost optimization algorithm code? I will manually translate it into OCaml then. Forgive me, if I missed it on Wikipedia: there are too many algos on flow networks for the first day!

  Read the article

• Iphone & Web App synch

  - by Jack Welsh

  I am trying to build an Iphone App client for our CRM solution so our sales people would be able to access the information available in our CRM through an Iphone App. I am trying to find out what is the recommended approach to architect the application when it comes to the database. I am not sure where should the data reside, should I save a subset of the data on the iPhone, or should I just rely on webservices and pull the information I need from the database whenever I need it. Also, is there any best practices or frameworks to build such applications on the Iphone.

  Read the article

• Small methods - Small sprocs

  - by Berlioz

  Uncle Bob recommends having small methods. Do stored procedures have an ideal size? Or can they run on for 100's and 100's of lines long? Also does anyone have anything to say about where to place business logic. If located in stored procedures, the database is being used as data processing tier. If you read Adam Machanic, his bias is toward the database, does that imply long stored procedures that only the author of the sproc understands, leaving maintainers to deal with the mess? I guess there is two inter-related questions, somehow. Thanks in advance for responding to a fuzzy question(s).

  Read the article

• SQL Server Import table keeping default values

  - by Chrissi

  I am importing a table from one database to another in SQL Server 2008 by right-clicking the target database and choosing Tasks Import Data... When I import the table I get the column names and types and all the data fine, but I lose the primary key, identity specifications and all the default values that were set in the source table. So now I have to set all the default values for each column again manually. Is there any way to get the default values with the import, or even after with a Query? I am VERY new to this and flailing in the dark, so forgive me if this is a really stupid question...

  Read the article

• How to order the items in a nested LINQ-provided collection

  - by Carson McComas

  I've got a (SQL Server) database table called Category. And another database table called SubCategory. SubCategory has a foreign key relationship to Category. Because of this, thanks to LINQ, each Cateogory has a property called SubCategories and LINQ is nice enough to return all the SubCategories associated with my Category when I grab it. If I want to sort the Categories alphabetically, I can just do: return db.Categories.OrderBy(c => c.Name); However, I have no idea how to order the SubCategories collection inside each Category. My goal is to return a collection of Categories, where all of the SubCategory collections inside of them are ordered alphabetically by Name.

  Read the article

• Problem with SQL syntax (probably simple)

  - by Bryan Folds

  I'm doing some custom database work for a module for Drupal and I get the following SQL error when trying to create my table: user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DEFAULT NULL, rooms INT DEFAULT NULL, adults INT DEFAULT NULL, children' at line 14 query: CREATE TABLE dr_enquiry ( eId INT unsigned NOT NULL auto_increment, eKey VARCHAR(16) NOT NULL, dateSent INT NOT NULL DEFAULT 0, status VARCHAR(30) NOT NULL DEFAULT 'Unanswered', custName VARCHAR(50) NOT NULL, custEmail VARCHAR(200) NOT NULL, custPhone VARCHAR(25) NOT NULL, custCountry VARCHAR(40) NOT NULL, custIP VARCHAR(11) DEFAULT NULL, offerName VARCHAR(100) NOT NULL, offerURL VARCHAR(200) NOT NULL, arrival DATETIME DEFAULT NULL, departure DEFAULT NULL, rooms INT DEFAULT NULL, adults INT DEFAULT NULL, children INT DEFAULT NULL, childAges VARCHAR(32) DEFAULT NULL, toddlers INT DEFAULT NULL, toddlerAges VARCHAR(32) DEFAULT NULL, catering VARCHAR(255) DEFAULT NULL, comments VARCHAR(255) DEFAULT NULL, agent VARCHAR(100) DEFAULT NULL, voucher VARCHAR(100) DEFAULT NULL, PRIMARY KEY (eId) ) /*!40100 DEFAULT CHARACTER SET UTF8 */ in /home/travelco/public_html/includes/database.inc on line 550.

  Read the article

• .Remove(object) on a List<T> returned from LINQ to SQL compiled query won't delete the Object right

  - by soldieraman

  I am returning two lists from the database using LINQ to SQL compiled query. While looping the first list I remove duplicates from the second list as I dont want to process already existing objects again. eg. //oldCustomers is a List returned by my Compiled Linq to SQL Statmenet that I have added a .ToList() at the end to //Same goes for newCustomers for (Customer oC in oldCustomers) { //Do some processing newCustomers.Remove(newCusomters.Find(nC=> nC.CustomerID == oC.CusomterID)); } for (Cusomter nC in newCustomers) { //Do some processing } DataContext.SubmitChanges() I expect this to only save the changes that have been made to the customers in my processing and not Remove or Delete any of my customers from the database. Correct? I have tried it and it works fine - but I am trying to know if there is any rare case it might actually get removed

  Read the article

• Counting the most tagged tag with MySQL

  - by Jack W-H

  Hi folks My problem is that I'm trying to count which tag has been used most in a table of user-submitted code. But the problem is with the database structure. The current query I'm using is this: SELECT tag1, COUNT(tag1) AS counttag FROM code GROUP BY tag1 ORDER BY counttag DESC LIMIT 1 This is fine, except, it only counts the most often occurence of tag1 - and my database has 5 tags per post - so there's columns tag1, tag2, tag3, tag4, tag5. How do I get the highest occurring tag value from all 5 columns in one query? Jack

  Read the article

• Upgraded activerecord-sqlserver-adapter from 2.2.22 to 2.3.8 and now getting an ODBC error

  - by stuartc

  I have been using MSSQL 2005 with Rails for quite a while now, and decided to bump my gems up on one of my projects and ran into a problem. I moved from 2.2.22 to 2.3.8 (latest as of writing) and all of a sudden I got this: ODBC::Error: S1090 (0) [unixODBC][Driver Manager]Invalid string or buffer length I'm using a DSN connection with FreeTDS my database.yml looks like this: adapter: sqlserver mode: ODBC dsn: 'DRIVER=FreeTDS;TDSVER=7.0;SERVER=10.0.0.5;DATABASE=db;Port=1433;UID=user;PWD=pwd;' Now in the mean time I moved back to 2.2.22 and there are no deprecation warnings and everything seems fine but obviously for the sake of being up to date, any ideas what could have changed in the adaptor that could cause this?

  Read the article

• How to create temporary files on the client machine, from Web Application?

  - by Gaurav Srivastava

  I am creating a Web Application using JSP, Struts, EJB and Servlets. The Application is a combined CRM and Accounting Package so the Database size is very huge. So, in order to make Execution faster, I want prevent round trips to the Database. For that purpose, what I want to do is create some temporary XML files on the client Machine and use them whenever required. How can I do this, as Javascript do not permits me to do so. Is there any way of doing this? Or, is there any other solution which I can adopt in order to make my application Faster?

  Read the article

• Flashing and closing PyS60 SIS

  - by Matrich

  I created a py script for S60 2nd Edition FP3 with a background image, database, sound files which are stored in a folder on c drive. After several hours, I have managed to convert it into sis which I sent to my mobile phone. First, I installed the sis on the external memory and it failed to work. I read online that it should be on the same drive as python runtime. So I installed it on phone memory but it just flashes and then closes. I made another sis with a database and it worked so I suspect it could be because it cant find the background image and sound files in the folder. How can I know the cause of this? Also, how can I include the background image and sound files with the sis so that they are automatically installed when installing the sis file?

  Read the article

• Classes to Entities; Like-class inheritence problems

  - by Stacey

  Beyond work, some friends and I are trying to build a game of sorts; The way we structure some of it works pretty well for a normal object oriented approach, but as most developers will attest this does not always translate itself well into a database persistent approach. This is not the absolute layout of what we have, it is just a sample model given for sake of representation. The whole project is being done in C# 4.0, and we have every intention of using Entity Framework 4.0 (unless Fluent nHibernate can really offer us something we outright cannot do in EF). One of the problems we keep running across is inheriting things in database models. Using the Entity Framework designer, I can draw the same code I have below; but I'm sure it is pretty obvious that it doesn't work like it is expected to. To clarify a little bit; 'Items' have bonuses, which can be of anything. Therefore, every part of the game must derive from something similar so that no matter what is 'changed' it is all at a basic enough level to be hooked into. Sounds fairly simple and straightforward, right? So then, we inherit everything that pertains to the game from 'Unit'. Weights, Measures, Random (think like dice, maybe?), and there will be other such entities. Some of them are similar, but in code they will each react differently. We're having a really big problem with abstracting this kind of thing into a database model. Without 'Enum' support, it is proving difficult to translate into multiple tables that still share a common listing. One solution we've depicted is to use a 'key ring' type approach, where everything that attaches to a character is stored on a 'Ring' with a 'Key', where each Key has a Value that represents a type. This works functionally but we've discovered it becomes very sluggish and performs poorly. We also dislike this approach because it begins to feel as if everything is 'dumped' into one class; which makes management and logical structure difficult to adhere to. I was hoping someone else might have some ideas on what I could do with this problem. It's really driving me up the wall; To summarize; the goal is to build a type (Unit) that can be used as a base type (Table per Type) for generic reference across a relatively global scope, without having to dump everything into a single collection. I can use an Interface to determine actual behavior so that isn't too big of an issue. This is 'roughly' the same idea expressed in the Entity Framework.

  Read the article

• Is there a more expressive way of executing SQL query using Qt?

  - by ShaChris23

  I currently have this code: // Construct query QString const statement = QString("drop database if exists %1") .arg(databaseName_); QSqlQuery query(db); query.exec(statement); Is there a better way to code than the above? Specifically, I dont like how I use QString for SQL statement. It'd be nice if Qt has some class so that I could do something like: // Construct query QSomeClass statement = "drop database if exists %1"; statement.setArg(1, databaseName_); // Replace all %1 in the original string. QSqlQuery query(db); query.exec(statement);

  Read the article

• Losing DateTimeOffset precision when using C#

  - by Darvis Lombardo

  I have a SQL Server table with a CreatedDate field of type DateTimeOffset(2). A sample value which is in the table is 2010-03-01 15:18:58.57 -05:00 As an example, from within C# I retrieve this value like so: var cmd = new SqlCommand("SELECT CreatedDate FROM Entities WHERE EntityID = 2", cn); var da = new SqlDataAdapter(cmd); DataTable dt =new DataTable(); da.Fill(dt); And I look at the value: MessageBox.Show(dt.Rows[0][0].ToString()); The result is 2010-03-01 15:18:58 -05:00, which is missing the .57 that is stored in the database. If I look at dt.Rows[0][0] in the Watch window, I also do not see the .57, so it appears it has been truncated. Can someone shed some light on this? I need to use the date to match up with other records in the database and the .57 is needed. Thanks! Darvis

  Read the article

• How to perform COUNT() or COUNT(*)

  - by ninumedia

  I have a list of tags in a database. Ex: villan hero spiderman superman superman I wanted to obtain a sorted list of the tag names in ascending order and the number of times the unique tag appeared in the database. I wrote this code: Ex: SELECT hashtag.tag_name, COUNT( * ) AS number FROM hashtag GROUP BY hashtag.tag_name ORDER BY hashtag.tag_name ASC This yields the correct result: hero - 1 spiderman - 1 superman - 2 villan - 1 How can I obtain the full COUNT of this entire list. The answer should be 4 in this case because there are naturally 4 rows. I can't seem to get a correct COUNT() without the statement failing. Thanks so much for the help! :)

  Read the article

• How to use a variable to specify filegroup in MSSQL

  - by gt

  I want to alter a table to add a constraint during upgrade on a MSSQL database. This table is normally indexed on a filegroup called 'MY_INDEX' - but may also be on a database without this filegroup. In this case I want the indexing to be done on the 'PRIMARY' filegroup. I tried the following code to achieve this: DECLARE @fgName AS VARCHAR(10) SET @fgName = CASE WHEN EXISTS(SELECT groupname FROM sysfilegroups WHERE groupname = 'MY_INDEX') THEN QUOTENAME('MY_INDEX') ELSE QUOTENAME('PRIMARY') END ALTER TABLE [dbo].[mytable] ADD CONSTRAINT [PK_mytable] PRIMARY KEY ( [myGuid] ASC ) ON @fgName -- fails: 'incorrect syntax' However, the last line fails as it appears a filegroup cannot be specified by variable. Is this possible?

  Read the article

• How do I hide data/field in a List in J2ME

  - by pi

  Hi, I am working on a J2ME app which has dynamically generated Lists. Items on this list may be consequently selected, and the selection processed within the commandAction block. Is there a way to have the IDs of variables populating the List (from a remote database) included in the List item definition as in: this.append("A", null); this.append("B", null); or: String[] arrayOfValues = {"A", "B"}; new List("Menu", List.IMPLICIT, arrayOfValues, null); such that when an item is selected, perhaps A, I can also have its database ID for perhaps further processing. Is it possible to hide a field/data? Thanks.

  Read the article

• Prevent sqlite INJECTION ATTACKS on your own iPhone?

  - by Bonnie

  I always take precautions regarding SQL INJECTION ATTACKS when data is saved between someone's iPhone and a remote database on the cloud. But is it also necessary to do the same... when just saving data (using sqlite) from someone's cell phone, to a database that's just on their own phone? What's the worse they can do? Delete their own data (or tables) on their own phone? (If they really try hard enough.) Thanks.

  Read the article

• Auto Generated - CREATE Table Script in SQL 2008 throws error

  - by jack

  I scripted the tables in my dev database using SQL 2008 - generate scripts option (Datbase-right click-Tasks-Generate Scripts) and ran it on the staging database, but the script throws the below error for each table Msg 102, Level 15, State 1, Line 1 Incorrect syntax near '('. Msg 319, Level 15, State 1, Line 15 Incorrect syntax near the keyword 'with'. If this statement is a common table expression, an xmlnamespaces clause or a change tracking context clause, the previous statement must be terminated with a semicolon. Below is the script for one of my table ALTER TABLE [dbo].[Customer]( [CustomerID] [int] IDENTITY(1,1) NOT NULL, [FirstName] [nvarchar](500) NULL, [LastName] [nvarchar](500) NULL, [DateOfBirth] [datetime] NULL, [EmailID] [nvarchar](200) NULL, [ContactForOffers] [bit] NULL, CONSTRAINT [PK_Customer] PRIMARY KEY CLUSTERED ( [CustomerID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO Any help will be much appreciated.

  Read the article

• Howt o get the t-sql statements being used to Update a DataSet

  - by Dennis

  I've a c# DataSet object with one table in it, and put some data in it and i've made some changes to that dataset (by code). Is there a way to get the actual t-sql queries this dataset will perform on the sql server when I update the dataset to the database with code that looks something like this: var dataAdapter = new SqlDataAdapter(cmdText, connection); var affected = dataAdapter.Update(updatedDataSet); I want to know what queries this dataset will fire to the database so I can log these changes to a logfile in my c# program.

  Read the article

• Finding Cities within 'X' Kilometers (or Miles)

  - by Mike Curry

  This may or may not be clear, leave me a comment if I am off base, or you need more information. Perhaps there is a solution out there already for what I want in PHP. I am looking for a function that will add or subtract a distance from a longitude OR latitude value. Reason: I have a database with all Latitudes and Longitudes in it and want to form a query to extract all cities within X kilometers (or miles). My query would look something like this... Select * From Cities Where (Longitude > X1 and Longitude < X2) And (Latitude > Y1 and Latitude < Y2) Where X1 = Longitude - (distance) Where X2 = Longitude + (distance) Where Y1 = Latitude - (distance) Where Y2 = Latitude + (distance) I am working in PHP, with a MySql Database. Open to any suggestions also! :)

  Read the article

< Previous Page | 675 676 677 678 679 680 681 682 683 684 685 686  | Next Page >