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  • Many to Many delete in NHibernate two parents with common association

    - by Joshua Grippo
    I have 3 top level entities in my app: Circuit, Issue, Document Circuits can contain Documents and Issues can contain Documents. When I delete a Circuit, I want it to delete the documents associated with it, unless it is used by something else. I would like this same behavior with Issues. I have it working when the only association is in the same table in the db, but if it is in another table, then it fails due to foreign key constraints. ex 1(This will cascade properly, because there is only a foreign constraint from Circuit to Document) Document1 exists. Circuit1 exists and contains a reference to Document1. If I delete Circuit1 then it deletes Document1 with it. ex 2(This will cascade properly, because there is only a foreign constraint from Circuit to Document.) Document1 exists. Circuit1 exists and contains a reference to Document1. Circuit2 exists and contains a reference to Document1. If I delete Circuit1 then it is deleted, but Document1 is not deleted because Circuit2 exists. If I then delete Circuit2, then Document1 is deleted. ex 3(This will throw an error, because when it deletes the Circuit it sees that there are no other circuits that reference the document so it tries to delete the document. However it should not, because there is an Issue that has a foreign constraint to the document.) Document 1 exists. Circuit1 exists and contains a reference to Document1. Issue1 exists and contains a reference to Document1. If I delete Circuit1, then it fails, because it tries to delete Document1, but Issues1 still has a reference. DB: This think won't let upload an image, so here is the ERD to the DB: http://lh3.ggpht.com/_jZWhe7NXay8/TROJhOd7qlI/AAAAAAAAAGU/rkni3oEANvc/CircuitIssues.gif Model: public class Circuit { public virtual int CircuitID { get; set; } public virtual string CJON { get; set; } public virtual IList<Document> Documents { get; set; } } public class Issue { public virtual int IssueID { get; set; } public virtual string Summary { get; set; } public virtual IList<Model.Document> Documents { get; set; } } public class Document { public virtual int DocumentID { get; set; } public virtual string Data { get; set; } } Mapping Files: <?xml version="1.0" encoding="utf-8"?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="Model" assembly="Model"> <class name="Circuit" table="Circuit"> <id name="CircuitID"> <column name="CircuitID" not-null="true"/> <generator class="identity" /> </id> <property name="CJON" column="CJON" type="string" not-null="true"/> <bag name="Documents" table="CircuitDocument" cascade="save-update,delete-orphan"> <key column="CircuitID"/> <many-to-many class="Document"> <column name="DocumentID" not-null="true"/> </many-to-many> </bag> </class> </hibernate-mapping> <?xml version="1.0" encoding="utf-8"?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="Model" assembly="Model"> <class name="Issue" table="Issue"> <id name="IssueID"> <column name="IssueID" not-null="true"/> <generator class="identity" /> </id> <property name="Summary" column="Summary" type="string" not-null="true"/> <bag name="Documents" table="IssueDocument" cascade="save-update,delete-orphan"> <key column="IssueID"/> <many-to-many class="Document"> <column name="DocumentID" not-null="true"/> </many-to-many> </bag> </class> </hibernate-mapping> <?xml version="1.0" encoding="utf-8"?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="Model" assembly="Model"> <class name="Document" table="Document"> <id name="DocumentID"> <column name="DocumentID" not-null="true"/> <generator class="identity" /> </id> <property name="Data" column="Data" type="string" not-null="true"/> </class> </hibernate-mapping> Code: using (ISession session = sessionFactory.OpenSession()) { var doc = new Model.Document() { Data = "Doc" }; var circuit = new Model.Circuit() { CJON = "circ" }; circuit.Documents = new List<Model.Document>(new Model.Document[] { doc }); var issue = new Model.Issue() { Summary = "iss" }; issue.Documents = new List<Model.Document>(new Model.Document[] { doc }); session.Save(circuit); session.Save(issue); session.Flush(); } using (ISession session = sessionFactory.OpenSession()) { foreach (var item in session.CreateCriteria<Model.Circuit>().List<Model.Circuit>()) { session.Delete(item); } //this flush fails, because there is a reference to a child document from issue session.Flush(); foreach (var item in session.CreateCriteria<Model.Issue>().List<Model.Issue>()) { session.Delete(item); } session.Flush(); }

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  • Trasnfer of dirctory structure on network

    - by singh
    Hi I am designing a remote CD/DVD burner to address hardware constraint on my Machine. My design work like that :(Analogous to network paper printer) Unix Based Machine (acts as server) hosts a burner. Windows based machine acts as client. Client prepare data to be burn and transfer it to server. Server burn the data on CD/DVD. My Question is : . Which is the best protocol to transfer data over network (Keeping same Directory hierarchy) between different OS

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  • XSLT1.0: remove duplicates combined with an xsl:key

    - by Jannibal
    I have the following piece of XML: <research> <research.record> <research.record_number>1</research.record_number> <research.type> <value lang="en-US">some research type</value> </research.type> <research.type> <value lang="en-US">some other type of research</value> </research.type> <project.record> <priref>101</priref> <project.type> <value lang="en-US">some type of project</value> </project.type> </project.record> </research.record> </research> <research> <research.record> <research.record_number>2</research.record_number> <research.type> <value lang="en-US">some other type of research</value> </research.type> <research.type> <value lang="en-US">a third type of research</value> </research.type> <project.record> <priref>101</priref> <project.type> <value lang="en-US">some type of project</value> </project.type> </project.record> </research.record> </research> <research> <research.record> <research.record_number>3</research.record_number> <research.type> <value lang="en-US">some other type of research</value> </research.type> <research.type> <value lang="en-US">a fourth type</value> </research.type> <project.record> <priref>201</priref> <project.type> <value lang="en-US">some other type of project</value> </project.type> </project.record> </research.record> </research> <research> ... etc ... With XSLT 1.0 I transform this XML into a list of unique project records by using xsl:key. So far, so good... The problem is: I also want to show unique research types for each unique project record. My wanted output would be: project.record 101: some research type, some other type of research, a third type of research project.record 201: some other type of research, a fourth type Hope someone can help me out with the right XSLT/XPATH. (Can only use XSLT1.0)

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  • App Engine Django Form Uniqueness Validation?

    - by GeekTantra
    Is there a simpler way to use uniqueness validation with Django Forms in AppEngine? I understand that performance would be problem if we keep an uniqueness constraint but since the amount of data being added is very small performance is not a big concern, rather development time is a concern here. Any help is appreciated.

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  • Postgresql 9.1: ERROR: type "citext" does not exist

    - by gotuskar
    I am trying to execute following query through PgAdmin utility. CREATE TABLE svcr."EventLogs" ("eventId" BIGINT NOT NULL, "eventTime" TIMESTAMP WITH TIME ZONE NOT NULL, "userid" CITEXT, "realmid" CITEXT NOT NULL, "onUserid" CITEXT, "description" TEXT, CONSTRAINT eventlogs_pkey PRIMARY KEY ("eventId")); And I get following error - ERROR: type "citext" does not exist SQL state: 42704 Character: 120 However, following query runs fine - CREATE TABLE svcr."CategoryMap" ("category" INT NOT NULL, "userData" INT NOT NULL); What is wrong with the first query?

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  • B-trees, databases, sequential inputs, and speed.

    - by IanC
    I know from experience that b-trees have awful performance when data is added to them sequentially (regardless of the direction). However, when data is added randomly, best performance is obtained. This is easy to demonstrate with the likes of an RB-Tree. Sequential writes cause a maximum number of tree balances to be performed. I know very few databases use binary trees, but rather used n-order balanced trees. I logically assume they suffer a similar fate to binary trees when it comes to sequential inputs. This sparked my curiosity. If this is so, then one could deduce that writing sequential IDs (such as in IDENTITY(1,1)) would cause multiple re-balances of the tree to occur. I have seen many posts argue against GUIDs as "these will cause random writes". I never use GUIDs, but it struck me that this "bad" point was in fact a good point. So I decided to test it. Here is my code: SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[T1]( [ID] [int] NOT NULL CONSTRAINT [T1_1] PRIMARY KEY CLUSTERED ([ID] ASC) ) GO CREATE TABLE [dbo].[T2]( [ID] [uniqueidentifier] NOT NULL CONSTRAINT [T2_1] PRIMARY KEY CLUSTERED ([ID] ASC) ) GO declare @i int, @t1 datetime, @t2 datetime, @t3 datetime, @c char(300) set @t1 = GETDATE() set @i = 1 while @i < 2000 begin insert into T2 values (NEWID(), @c) set @i = @i + 1 end set @t2 = GETDATE() WAITFOR delay '0:0:10' set @t3 = GETDATE() set @i = 1 while @i < 2000 begin insert into T1 values (@i, @c) set @i = @i + 1 end select DATEDIFF(ms, @t1, @t2) AS [Int], DATEDIFF(ms, @t3, getdate()) AS [GUID] drop table T1 drop table T2 Note that I am not subtracting any time for the creation of the GUID nor for the considerably extra size of the row. The results on my machine were as follows: Int: 17,340 ms GUID: 6,746 ms This means that in this test, random inserts of 16 bytes was almost 3 times faster than sequential inserts of 4 bytes. Would anyone like to comment on this? Ps. I get that this isn't a question. It's an invite to discussion, and that is relevant to learning optimum programming.

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  • I am looking for a System level activity logging application for Symbian

    - by Prashant
    Is there any free application available for logging all the activity ( both user initiated and system initiated ) on Symbian along with state of various resource variables on device (like Memory , I/O, Media player etc ). I want to use it to examine if there is any dependency /conflict /resource constraint when multiple Application are running . Any pointer in this direction will be greatly appreciated .

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  • Does table (string, string) require index?

    - by abatishchev
    In my database running on SQL Server 2008 R2 I have a special table for global variables: CREATE TABLE global_variables ( name NVARCHAR(50), value NVARCHAR(50) NOT NULL CONSTRAINT PK_global_variables PRIMARY KEY CLUSTERED ( name 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 Does such table require indexing on value or not?

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  • How do I limit JPQ output?

    - by den-javamaniac
    I need to limit number of entities returned by a query to some certain value inside a JPA query (through JPQL). Particularly: select m from Manual m //constraint e.g. in sql (mysql syntax) I would do it like: select * from Manual limit 1 The only solution that comes up is simply to get all entities and then choose first one, which is out of the issue. Any ideas?

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  • postgresql insert value in table in serial value

    - by Jesse Siu
    my database using postgresql. the table pk is uing serial value.if i want to insert a record in table, do i need type pk or it will automatic contain id. Can you give me a example about how to insert a record in dataset CREATE TABLE dataset ( id serial NOT NULL, age integer NOT NULL, name character varying(32) NOT NULL, description text NOT NULL DEFAULT ''::text CONSTRAINT dataset_pkey PRIMARY KEY (id ) )

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  • Not able to add column value

    - by peter
    I have project which contain 4 tables among these shedule table Session column i am not able to add vaue,,this table contain three foriegn key from two tables(in which single table has two foreign keys here) i added values here..Any one has any idea about this..Actually my intention is to remove the error "the insert statement conflicted with the foreign key constraint sql server"

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  • Infinite sharing system (PHP/MySQLi)

    - by Toine Lille
    I'm working on a discount system for whichever customer shares a product and brings in new customers. Each unique visit = $0.05 off, each new customer = $0.50 off (it's a cheap product so yeah, no big numbers). When a new customer shares the site, the customer initially responsible for the new customer (if any) will get half of the new customer's discount as well. The initial customer would get a fourth for the next level and the new customer half of that, etc, creating a tree or pyramid that way that could be infinite. Initial customer ($1.35 discount: 2 new+3 visits + half of 1 new+2 visits) Visitor ($0) Visitor ($0) New customer ($0.60) Visitor ($0) Visitor ($0) Newer customer ($0) New customer ($0) Visitor ($0) The customers are saved along with their IP addresses (bin2hex(inet_pton)) in a database table (customers) with info like a unique id, e-mail address and first date/time the purchased a product (= time of registration). The shares are saved in a separate table within the same database (sharing). Each unique IP addresses that visits the site creates a new row featuring the IP address (also saved as bin2hex(inet_pton)), the id of the customer who shared it and the date/time of the visit. Sharing goes via URL, featuring a GET element containing the customer's id. Visits and new customers overlap, as visits will always occur before the new customer does. That's fine. The date/times are used just to make it a little more secure (I also use the IP along with cookies to see if people cheat the system). If an IP is already in the sharing or customer tables, it does not count and will not create a new entry. Now the problem is, how to make the infinity happen and apply the different values to it? That's all I'd need to know. It needs to calculate the discount for each customer separately, but also allow for monitoring altogether (though that's just a matter of passing all ID's through it). I figured I'd start (after the database connection) with $stmt = $con->prepare('SELECT ip,datetime FROM sharing WHERE sender=?'); $stmt->bind_param('i',$customerid); $stmt->execute(); $stmt->store_result(); $discount = $discount + ($stmt->num_rows * 0.05); $stmt->bind_result($ip,$timeofsharing); to translate all the visits to $0.05 of discount each. To check for the new customers that came from these visits, I wrote the following: while ($sql->fetch()) { $stmt2 = $con->prepare("SELECT datetime FROM users WHERE ip=?"); $stmt2->bind_param('s',$ip); $stmt2->execute(); $stmt2->store_result(); $stmt2->bind_result($timeofpurchase); Followed by a little more security comparing the datetimes: while ($stmt2->fetch()) { if (strtotime($timeofpurchase) < strtotime($timeofsharing)) { $discount = $discount + $0.50; } But this is just for the initial customer's direct results. If I'd want to check for the next level, I'd basically have to put the exact same check and loop in itself, checking each new customer the initial customer they brought to the site, and then for the next level again to check all of the newer customers, etc, etc. What to do? / Where to go? / What would be the correct practice for this? Thanks!

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  • Is there a command to test an SQL query without executing it? ( MySQL or ANSI SQL )

    - by Petruza
    Is there anything like this: TEST DELETE FROM user WHERE somekey = 45; That can return any errors, for example that somekey doesn't exist, or some constraint violation or anything, and reporting how many rows would be affected, but not executing the query? I know you can easily turn any query in a select query that has no write or delete effect in any row, but that can lead to errors and it's not very practical if you want to test and debug many queries.

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  • Can I set ignore_dup_key on for a primary key?

    - by Mr. Flibble
    I have a two-column primary key on a table. I have attempted to alter it to set the ignore_dup_key to on with this command: ALTER INDEX PK_mypk on MyTable SET (IGNORE_DUP_KEY = ON); But I get this error: Cannot use index option ignore_dup_key to alter index 'PK_mypk' as it enforces a primary or unique constraint. How else should I set IGNORE_DUP_KEY to on?

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  • Using a model to represent the overall state of a view

    - by James P.
    Is there a standard practise for representing the state of a user interface that is not linked to a single Component? For example, a Swing interface could have a series of tabs with a constraint that a single tab should only be displayed once per a given entity type (this could be represented as a HashSet). Or a message could give the result of the last operation carried out. Or a JPanel could be linked to a single entity instance for editing purposes.

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  • Drop all foreign keys in a table

    - by trnTash
    I had this script which worked in sql server 2005 -- t-sql scriptlet to drop all constraints on a table DECLARE @database nvarchar(50) DECLARE @table nvarchar(50) set @database = 'dotnetnuke' set @table = 'tabs' DECLARE @sql nvarchar(255) WHILE EXISTS(select * from INFORMATION_SCHEMA.TABLE_CONSTRAINTS where constraint_catalog = @database and table_name = @table) BEGIN select @sql = 'ALTER TABLE ' + @table + ' DROP CONSTRAINT ' + CONSTRAINT_NAME from INFORMATION_SCHEMA.TABLE_CONSTRAINTS where constraint_catalog = @database and table_name = @table exec sp_executesql @sql END It does not work in SQL Server 2008. How can I easily drop all foreign key constraints for a certain table? Does anyone have a better script?

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  • jpa relationship-Google app engine

    - by megala
    I created two tables in google appengine datastore using JPA. Table1: *groupname pk *groupid *groupdesc *emailper Table2: *groupname *memberid *membername My constraint is if i enter data into table2 it check whether group already exists or not in table.If exists than only it store the data into table .How to solve this?

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  • Is a primary key automatically an index?

    - by Lieven Cardoen
    If I run Profiler, then it suggests a lot of indexes like this one CREATE CLUSTERED INDEX [_dta_index_Users_c_9_292912115__K1] ON [dbo].[Users] ( [UserId] ASC )WITH (SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF) ON [PRIMARY] UserId is the primary key of the table Users. Is this index better than the one already in the table: ALTER TABLE [dbo].[Users] ADD CONSTRAINT [PK_Users] PRIMARY KEY NONCLUSTERED ( [UserId] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

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  • how to save related models with non-null foreign key

    - by Fortress
    I have a model called user which has_one email. I put the foreign key (NOT NULL) inside users table. Now I'm trying to save it in the following way: @email = Email.new(params[:email]) @email.user = User.new(params[:user]) @email.save This raises a db exception, because the foreign key constraint is not met (NULL is inserted into email_id). How can I elegantly solve this or is my data modeling wrong?

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  • SQL Server identity counterpart problem

    - by Guru
    Hi there, I'm using SQL Server and I want to use identity constraint in it I know how to use it in following manner create table mytable ( c1 int primary key identity(1,1); ) the above code works fine but what if i want the identity column to have values as EMP001, EMP002,... instead of 1,2.... Thanks in advance, Guru

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  • What is the difference between check and foreign key?

    - by GigaPr
    Hi, i am quite confused about the difference between a FOREIGN KEY and CHECK constraint. they appear to me to achieve the same result. I mean I could create a table and enforce a Foreign key on another table, but i could create a CHECK to ensure the value in in another table. What is the difference and when to use the one or the other? thanks

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