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  • how does sql count work?

    - by ria
    I would like to understand how exactly does sql count work. Is it a whole table scan that happens or is it some property of the table that is read. However I feel a table scan would be an overhead in case of huge tables with lots of records.

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  • How to use Transaction in Entity FrameWork?

    - by programmerist
    How to use Transaction in Entity FrameWork? i read some links on Stackoverflow : http://stackoverflow.com/questions/815586/entity-framework-using-transactions-or-savechangesfalse-and-acceptallchanges BUT; i have 3 table so i have 3 entities: CREATE TABLE Personel (PersonelID integer PRIMARY KEY identity not null, Ad varchar(30), Soyad varchar(30), Meslek varchar(100), DogumTarihi datetime, DogumYeri nvarchar(100), PirimToplami float); Go create TABLE Prim (PrimID integer PRIMARY KEY identity not null, PersonelID integer Foreign KEY references Personel(PersonelID), SatisTutari int, Prim float, SatisTarihi Datetime); Go CREATE TABLE Finans (ID integer PRIMARY KEY identity not null, Tutar float); Personel, Prim,Finans my tables. if you look Prim table you can see Prim value float value if i write a textbox not float value my transaction must run. using (TestEntities testCtx = new TestEntities()) { using (TransactionScope scope = new TransactionScope()) { // do someyihng... testCtx.Personel.SaveChanges(); // do someyihng... testCtx.Prim.SaveChanges(); // do someyihng... testCtx.Finans.SaveChanges(); scope .Complete(); success = true; } } How can i do that?

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  • mysql add auto increment and a additional key

    - by Lee
    Hey all I am trying to alter a table with adding a new column setting it as auto increment and with a key. The table already has one key and this one will be an addition. The error I get is the following. error : Multiple primary key defined My code is: alter table user add column id int (11) NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST; I have also tries wrapping the key name ie alter table user add column id int (11) NOT NULL AUTO_INCREMENT PRIMARY (id) KEY FIRST; But still no luck. How can it be done ?

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  • mysql select query optimization

    - by Saharsh Shah
    I have two table testa & testb. CREATE TABLE `testa` ( `id` INT(10) NOT NULL AUTO_INCREMENT, `name` VARCHAR(50) DEFAULT NULL, PRIMARY KEY (`id`) ); CREATE TABLE `testb` ( `id` INT(10) NOT NULL AUTO_INCREMENT, `name` VARCHAR(50) DEFAULT NULL, `aid1` INT(10) DEFAULT NULL, `aid2` INT(10) DEFAULT NULL, `aid3` INT(10) DEFAULT NULL, PRIMARY KEY (`id`) ); Currently I am running below query for retrieving all rows where id in testa table matches with any columns of aid1,aid2,aid3 in tableb. The query is retreiving acurate result but it is taking minimum 30 seconds to execute which is too much. I have also tried to optimise my query using UNION but failed to do so. SELECT a.id, a.name, b.name, b.id FROM testb b INNER JOIN testa a ON b.aid1 = a.id OR b.aid2 = a.id OR b.aid3 = a.id ; How do i optimize my query so it's total execution time is within 2-3 seconds? Thanks in advance...

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  • Python: Lits containg tuples and long int.

    - by Yasmin
    I have a list containing a tuples and long integers the list looks like this: table = [(1L,), (1L,), (1L,), (2L,), (2L,), (2L,), (3L,), (3L,)] How do i convert the table to look like a formal list? so the output would be: table = ['1','1','1','2','2','2','3','3'] For information purposes the data was obtained from a mysql database.

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  • When and where should I add a view to a UITableView's footer?

    - by camelCase
    I am populating a UITableViewController's UITableView through code only. At the bottom of the table I wish to position a button that scrolls into view as the user scrolls to the bottom of the table. When in the UITableViewController life cycle should I populate the table footer with a button? viewDidLoad? p.s. I wish to avoid using section footers in the UITableView.

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  • Non-auto-increment rails/postgresql column

    - by Redian
    I'm trying to have a model/table with duplicate information in it. The reason for this is so that the same data can be written to the table under different users and found for each user. However, I want a quick easy way to identify which information is a duplicate of other information. I think the best way to do this would be to have an item_id of sorts that increments with each "set" of entries to the table. Is there a way to do this without including another table that stores the information without attributing it to users?

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  • Implementing Tagging System with PHP and mySQL. Caching help!!!

    - by Hamid Sarfraz
    With reference to this post: http://stackoverflow.com/questions/2122546/how-to-implement-tag-counting I have implemented the suggested 3 table tagging system completely. To count the number of Articles per tag, i am using another column named tagArticleCount in the tag definition table. (other columns are tagId, tagText, tagUrl, tagArticleCount). If i implement realtime editing of this table, so that whenever user adds another tag to article or deletes an existing tag, the tag_definition_table is updated to update the counter of the added/removed tag. This will cost an extra query each time any modification is made. (at the same time, related link entry for tag and article is deleted from tagLinkTable). An alternative to this is not allowing any real time editing to the counter, instead use CRONs to update counter of each tag after a specified time period. Here comes the problem that i want to discuss. This can be seen as caching the article count in database. Can you please help me find a way to present the articles in a list when a tag is explored and when the article counter for that tag is not up to date. For example: 1. Counter shows 50 articles, but there are infact 55 entries in the tag link table (that links tags and articles). 2. Counter shows 50 articles, but there are infact 45 extries in the tag link table. How to handle these 2 scenerios given in example. I am going to use APC to keep cache of these counters. Consider it too in your solution. Also discuss performance in the realtime / CRONNED counter updates.

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  • mysql query help please

    - by moustafa
    i have forum_topics table and have topics_posts table now i want to select from forum_topics where have no posts from topics_posts can any one give me the one syntax like this selct from * forum_topics where have no rows in topics_posts table

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  • Retrieve rows where a value exists within a comma separated list

    - by Klaaz
    I like to reverse this query: SELECT * FROM table WHERE status IN ( option,option1,option2 ); in a query like SELECT * FROM table WHERE status contains ( 'option' ); Where field 'status' column contains (by example): 'option,option1'. When I use SELECT * FROM table WHERE status LIKE '%option%' ); It also selects the rows with a 'status' column that only contains 'option1' Is this possible? example data: id,name,status 1,'test1','option,option1' 2,'test2','option,option2' 3,'test3','option2' 4,'test4','option2,option3' 5,'test5','option' SELECT * FROM table WHERE status contains ( 'option' ); This query should select select record 1,2 and 5. 'status' field type is varchar. The problem is that the status fields contains data that is almost alike, exept from the added number to option. Off course this is a made up example but the real thing has this kind of parameters

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  • Best datastructure for this relationship...

    - by Travis
    I have a question about database 'style'. I need a method of storing user accounts. Some users "own" other user accounts (sub-accounts). However not all user accounts are owned, just some. Is it best to represent this using a table structure like so... TABLE accounts ( ID ownerID -> ID name ) ...even though there will be some NULL values in the ownerID column for accounts that do not have an owner. Or would it be stylistically preferable to have two tables, like so. TABLE accounts ( ID name ) TABLE ownedAccounts ( accountID -> accounts(ID) ownerID -> accounts(ID) ) Thanks for the advice.

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  • Why does SQL Server 2000 treat SELECT test.* and SELECT t.est.* the same?

    - by Chris Pebble
    I butter-fingered a query in SQL Server 2000 and added a period in the middle of the table name: SELECT t.est.* FROM test Instead of: SELECT test.* FROM test And the query still executed perfectly. Even SELECT t.e.st.* FROM test executes without issue. I've tried the same query in SQL Server 2008 where the query fails (error: the column prefix does not match with a table name or alias used in the query). For reasons of pure curiosity I have been trying to figure out how SQL Server 2000 handles the table names in a way that would allow the butter-fingered query to run, but I haven't had much luck so far. Any sql gurus know why SQL Server 2000 ran the query without issue? Update: The query appears to work regardless of the interface used (e.g. Enterprise Manager, SSMS, OSQL) and as Jhonny pointed out below it bizarrely even works when you try: SELECT TOP 1000 dbota.ble.* FROM dbo.table

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  • Display xml data in silverlight datagrid, vb.net

    - by Aishwarya
    I want to display an xml file data in silverlight datagrid. im using the below code but it doesnt work.Please help. My vb.net code: Imports System Imports System.Collections.Generic Imports System.Linq Imports System.Windows Imports System.Windows.Controls Imports System.Xml.Linq Namespace SilverlightApplication1 Public Partial Class Page Inherits UserControl Public Sub New() InitializeComponent() End Sub Private Sub Page_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs) DataGrid1.ItemsSource = GetPunchReport() End Sub Public Function GetStatusReport() As List(Of Table) Dim statusReport As New List(Of Table)() Dim doc As XElement = XElement.Load("Data/PunchReport.xml") report = (From row In doc.Elements() _ Select GetStatus(row)).ToList() Return statusReport End Function Private Function GetReport(ByVal row As XElement) As Table Dim s As New Table() s.JobID= row.Attribute("JobID").Value s.VenueName= row.Attribute("VenueName").Value) Return s End Function End Class End Namespace

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  • [php,mysql] insert only adds upto 1000 records and ignoresall records after that.

    - by user560559
    Hello i have a large database where the client stores personal messages and fire email notifications [if allowed by the users]. certain users have the option of sending messages to their entire network of friends. some users have over 5000 friends in their network so if they select the whole network they'll be sending messages to over 5000 friends and system will store all the messages into a table. the problem is this that it does not insert more than 1000 records and ignores all inserts after the first 1000. i have increased the packet size, bulk_insert_buffer_size but still no luck. since the system stores some of the info in another table for reports, every insert returns its new message id. due to this i can not use the "insert into table (column1,column2) values (value1,value2) , (value1,value2)....etc." table engine is innodb, mysql version is 5.1.3 and is hosted on amazon web services. all i want is to fix this issue of inserting more than 1000 records at a time. as mentioned earlier, it works fine but only up to 1000 records and simply ignores all the records after that. i'm using php foreach(){} to insert message for each friend and if email is available, send notification to the user. this foreach(){} also inserts the same record in another table [with only 3 columns] for generating reports. thank you in advance for all the help and support. WMA.

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  • How to recalculate primary index?

    - by JohnM2
    I have table in mysql database with autoincrement PRIMARY KEY. On regular basis rows in this table are being deleted an added. So the result is that value of PK of the latest row is growing very fast, but there is not so much rows in this table. What I want to do is to "recalculate" PK in this way, that the first row has PK = 1, second PK = 2 and so on. There are no external dependencies on PK of this table so it would be "safe". Is there anyway it can be done using only mysql queries/tools? Or I have to do it from my code?

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  • Custom UITableViewCell from xib isn't displaying properly

    - by Kenny Wyland
    I've created custom UITableCells a bunch of times and I've never run into this problem, so I'm hoping you can help me find the thing I've missed or messed up. When I run my app, the cells in my table view appear to be standard cells with Default style. I have SettingsTableCell which is a subclass of UITableViewCell. I have a SettingsTableCell.xib which contains a UITableViewCell and inside that are a couple labels and a textfield. I've set the class type in the xib to be SettingsTableCell and the File's Owner of the xib to my table controller. My SettingsTableController has an IBOutlet property named tableCell. My cellForRowAtIndexPath contains the following code to load my table view xib and assign it to my table controller's tableCell property: static NSString *CellIdentifier = @"CellSettings"; SettingsTableCell *cell = (SettingsTableCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { [[NSBundle mainBundle] loadNibNamed:@"SettingsTableCell" owner:self options:nil]; cell = self.tableCell; self.tableCell = nil; NSLog(@"cell=%@", cell); } This is what my xib set up looks like in IB: When I run my app, the table displays as if all of the cells are standard Default style cells though: The seriously weird part is though... if I tap on the area of the cell where the textfield SHOULD be, the keyboard does come up! The textfield isn't visible, there's no cursor or anything like that... but it does respond. The visible UILabel is obviously not the UILabel from my xib though because the label in my xib is right justified and the one showing in the app is left justified. I'm incredibly confused about how this is happening. Any help is appreciated.

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  • How to show 0 when no row found

    - by user1685991
    I have a SQL query in which I am passing sysdate to the query problem is that when there is no matching date in table with sysdate then it don't shows the zero even if there is nvl applied here is my query select * from molasses where trunc(trn_dte) = trunc(sysdate) But it show data only when current date is present in table but I want to show zero if no data found in table.please help me to do this in oracle 10 g. Because some times the situation is like above and I have to display zero when no data found

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  • MEMORY(HEAP) vs. InnoDB in a Read and Write Envirnment

    - by Johannes
    I want to programm a real-time application using MySQL. It needs a small table (less than 10000 rows) that will be under heavy read (scan) and write (update and some insert/delete) load. I am really speaking of 10000 updates or selects per second. These statements will be executed on only a few (less than 10) open mysql connections. The table is small and does not contain any data that needs to be stored on disk. So I ask which is faster: InnoDB or MEMORY (HEAP)? My thoughts are: Both enginges will probably serve SELECTs directly from memory, as even InnoDB will cache the whole table. What about the UPDATAEs? (innodb_flush_log_at_trx_commit?) My main concern is the locking behavior: InnoDB row lock vs. MEMORY table lock. Will this present the bottleneck in the MEMORY implementation? Thanks for your thoughts!

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  • Doctrine 1.2 Column Naming Conventions for Many To Many Relationships

    - by Alan Storm
    I'm working with an existing database schema, and trying to setup two Doctrine models with a Many to Many relationship, as described in this document When creating tables from scratch, I have no trouble getting this working. However, the existing join tables use a different naming convention that what's described in the Doctrine document. Specifically Table 1 -------------------------------------------------- table_1_id ....other columns.... Table 2 -------------------------------------------------- table_2_id ....other columns.... Join Table -------------------------------------------------- fktable1_id fktable_2_id Basically, the previous developers prefaced all forign keys with an fk. From the examples I've seen and some brief experimenting with code, it appears that Doctrine 1.2 requires that the join table use the same column names as the tables it's joining in Is my assumption correct? If so, has the situation changed in Doctrine 2? If the answers to either of the above are true, how do you configure the models so that all the columns "line up"

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  • Unable to delete inherited entity class in EF4

    - by Coding Gorilla
    I have two entities in an EF4 model (using Model First), let's call them EntityA and EntityB. EntityA is marked as abstract, and EntityB inherits from EntityA. They are similar to the following: public class EntityA { public Guid Id; public string Name; public string Uri; } public class EntityB : EntityA { public string AnotherProperty; } The generated database tables look as I would expect them, with EntityA as on table, and then another table like: EntityA_EntityB Id (PK, FK, uniqueidentifier) AnotherProperty (varchar) There is a foreign key constraint on EntityA_EntityB that references EntityA's Id property, no cascades are configured (although I did try changing these myself). The problem is that when I attempt to do something like: Context.DeleteObject(EntityA_EntityB); EF attempts to delete the EntityA_EntityB table record before deleting the EntityA table record, which of course violates the foreign key constraint on EntityA_EntityB table. Using EFProfiler I see the following commands being sent to the database: delete [dbo].[EntityA_EntityB] where (([Id] = '5c02899f-09ea-2ed9-d44b-01aef80f6b64' /* @0 */) followed by delete [dbo].[EntityA] where ([Id] = '5c02899f-09ea-2ed9-d44b-01aef80f6b64' /* @0 */) I'm completely stumped as to how to get around this problem. I would think the EF should know that it needs to delete the base class first, before deleting the inherited class. I know I could do some triggers or other database type solutions, but I'd rather avoid doing that if I can. All my classes are POCO built using some customized T4 templates. I don't want to paste in a lot of extraneous code, but if you need more information I'll provide what I can.

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  • 42000 Syntax error in query when executing prepared statement

    - by Griff McGriff
    I have been pulling my hair out trying to swap my current script over to PDO. I have simplified the MySQL query for this example, but the error remains even with this version. $sql = 'SELECT * FROM :table WHERE lastUpdate > :appDate'; try{ $db = connect(); $stmt = $db->prepare($sql); $stmt->bindParam(':table', $table); $stmt->bindParam(':appDate', $appDate); foreach($tablesToCheck as $table){ $stmt->execute(); $resultset[] = $stmt->fetchAll(); } } catch(PDOException $e){ print 'Error!: '.$e->getMessage().'<br/>'; }//End try catch $stmt-errorInfo() returns: ( [0] => 42000 [1] => 1064 [2] => 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 ''GroupName' WHERE lastUpdate > NULL' at line 1 )

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  • Foreign Keys and Primary Keys at the same time

    - by Bader
    hello , i am trying to create table (orderdetails) , the table has two FKs and PKs at the same keys here is my code create table OrderDetails2 ( PFOrder_ID Number(3) PFProduct_ID Number(3) CONSTRAINT PF PRIMARY KEY (PFOrder_ID,PFProduct_ID), CONSTRAINT FK_1 FOREIGN KEY (PFProudct_ID) REFERENCES Product(Product_ID), CONSTRAINT FK_2 FOREIGN KEY (PFOrder_ID) REFERENCES Orderr(Order_ID) ); i am using Oracle express , a problem pops when i run the code , here is it ORA-00907: missing right parenthesis what is the problem ?

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  • How to create a reference tables for collection classes using fluent nhibernate

    - by Akk
    How can i create a 3 table schema from the following model classes. public class Product { public int Id {get; set;} public string Name {get; set;} public IList<Photo> Photos {get; set;} } public class Photo { public int Id {get; set;} public string Path {get; set;} } I want to create the following table structure in the database: Product ------- Id Name ProductPhotos ------------- ProductId (FK Products.Id) PhotoId (FK Photos.Id) Photos ------ Id Path How i can express the above Database Schema using Fluent NHibernate? I could only manage the following the Mapping but this does not get me the 3rd Photo ref table. public class ProductMap : ClassMap<Product> { public CityMap() { Id(x => x.Id); Map(x => x.Name); Table("Products"); HasMany(x => x.Photos).Table("ProductPhotos").KeyColumn("ProductId"); } }

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  • Rails - inheritance hierarchy of classes where an subtipe can play two roles

    - by Miquel
    I need to model Owners and Rentees in an application, so you have stuff that is always owned by someone and can be rented for someone else. I first approached this problem with Single Table Inheritance because both types of person will share all attributes, so you would have a model called Person associated to a table people with Owner and Rentee inheriting from Person. The problem is that Single type inheritance discerns subtypes using a field type and therefore a record in the table can represent either an Owner or a Rentee but not both at the same time, while in the real context you can have an Owner which is renting something from another Owner and therefore that person is at the same time an Owner and a Rentee. How would you approach this problem? Would you use separated tables fro owners and rentees? Is there any other type of table inheritance in Rails?

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  • IQueryable Where fails to work

    - by Steve
    I am using N-Hibernate and have a class/table called Boxers I also have a prospect table which tells use if the boxer is a prospect. (this table is one column of just the boxersID) So i Want to get all boxers that are prospects (meaning all boxers that have there id in the prospects table) Public static IQueryable<Boxer> IsProspect(this IQueryable<Boxer> query) { return query.Where(x => x.Prospect != null); } this doesnt trim down my list of boxers to the boxers that are prospect... yet if i debug and look at any boxer it will have True or false next to each one correctly... Why isnt the where clause correctly trimming down the list?

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