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  • DB design for master file in enterprise software

    - by Thang Nguyen
    Dear all. I want to write an enterprise software and now I'm in the DB design phase. The software will have some master data such as Suppliers, Customers, Inventories, Bankers... I considering 2 options: Put each of these on one separate table. The advantage: the table will have all necessary information for that kind of master file (Customer: name, address,.../Inventory: Type, Manufacturer, Condition...). Disadvantage: Not flexible. When I want to have a new type of master data, such as Insurer, I have to design another table. Put all in one table and this table have foreign key to another table which have type of each kind of master data (table 1: id, data_type, code, name, address....; table 2: data_type, data_type_name). Advantage: flexible - if I want more master data such as Insurer, I just put in table 2: code: 002, name: Insurer, and then put detail each insurer into table 1). Disadvantage: table 1 must have sufficient field to store all kind of information including: customer name, address, account, inventory's manufacturer, inventory's quality...). So which method do you usually do (or you think work better). Thank you very much

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  • ManyToOne annotation fails with Hibernate 4.1: MappingException

    - by barelas
    Using Hibernate 4.1.1.Final. When I try to add @ManyToOne, schema creation fails with: org.hibernate.MappingException: Could not instantiate persister org.hibernate.persister.entity.SingleTableEntityPersister User.java: @Entity public class User { @Id private int id; public int getId() {return id;} public void setId(int id) {this.id = id;} @ManyToOne Department department; public Department getDepartment() {return department;} public void setDepartment(Department department) {this.department = department;} } Department.java @Entity public class Department { @Id private int departmentNumber; public int getDepartmentNumber() {return departmentNumber;} public void setDepartmentNumber(int departmentNumber) {this.departmentNumber = departmentNumber;} } hibernate.properties: hibernate.connection.driver_class=com.mysql.jdbc.Driver hibernate.connection.url=jdbc:mysql://localhost:3306/dbname hibernate.connection.username=user hibernate.connection.password=pass hibernate.connection.pool_size=5 hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect hibernate.hbm2ddl.auto=create init (throwing exception): ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().buildServiceRegistry(); sessionFactory = new MetadataSources( serviceRegistrY.addAnnotatedClass(Department.class).addAnnotatedClass(User.class).buildMetadata().buildSessionFactory(); exception throwed at init: org.hibernate.MappingException: Could not instantiate persister org.hibernate.persister.entity.SingleTableEntityPersister at org.hibernate.persister.internal.PersisterFactoryImpl.create(PersisterFactoryImpl.java:174) at org.hibernate.persister.internal.PersisterFactoryImpl.createEntityPersister(PersisterFactoryImpl.java:148) at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:820) at org.hibernate.metamodel.source.internal.SessionFactoryBuilderImpl.buildSessionFactory(SessionFactoryBuilderImpl.java:65) at org.hibernate.metamodel.source.internal.MetadataImpl.buildSessionFactory(MetadataImpl.java:340) I have tried adding some other annotations, but shouldn't the defaults work and create the tables and foreign key? If I remove the department from User, tables get generated fine. Thanks in advance!

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  • Java: How to workaround the lack of Equatable interface?

    - by java.is.for.desktop
    Hello, everyone! As far as I know, things such as SortedMap or SortedSet, use compareTo (rather than equals) on Comparable<?> types for checking equality (contains, containsKey). But what if certain types are equatable by concept, but not comparable? I have to declare a Comparator<?> and override the method int compareTo(T o1, To2). OK, I can return 0 for instances which are considered equal. But, for unqeual instances, what do I return when an order is not evident? Is the approach of using SortedMap or SortedSet on equatable but (by concept) not comparable types good anyway? Thank you! EDIT: I don't want to store things sorted, but would I use "usual" Map and Set, I couldn't "override" the equality-behavior. EDIT 2: Why I can't just override equals(...): I need to alter the equality-behavior of a foreign class. Can't edit it. EDIT 3: Just think of .NET: They have IEquatable interface which cat alter the equality-behavior without touching the comparable behavior.

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  • autotools: no rule to make target all

    - by Raffo
    I'm trying to port an application I'm developing to autotools. I'm not an expert in writing makefiles and it's a requisite for me to be able to use autotools. In particular, the structure of the project is the following: .. ../src/Main.cpp ../src/foo/ ../src/foo/x.cpp ../src/foo/y.cpp ../src/foo/A/k.cpp ../src/foo/A/Makefile.am ../src/foo/Makefile.am ../src/bar/ ../src/bar/z.cpp ../src/bar/w.cpp ../src/bar/Makefile.am ../inc/foo/ ../inc/bar/ ../inc/foo/A ../configure.in ../Makefile.am The root folder of the project contains a "src" folder containing the main of the program AND a number of subfolders containing the other sources of the program. The root of the project also contains an "inc" folder containing the .h files that are nothing more than the definitions of the classes in "src", thus "inc" reflects the structure of "src". I have written the following configure.in in the root: AC_INIT([PNAME], [1.0]) AC_CONFIG_SRCDIR([src/Main.cpp]) AC_CONFIG_HEADER([config.h]) AC_PROG_CXX AC_PROG_CC AC_PROG_LIBTOOL AM_INIT_AUTOMAKE([foreign]) AC_CONFIG_FILES([Makefile src/Makefile src/foo/Makefile src/foo/A/Makefile src/bar/Makefile]) AC_OUTPUT And the following is ../Makefile.am SUBDIRS = src and then in ../src where the main of the project is contained: bin_PROGRAMS = pname gsi_SOURCES = Main.cpp AM_CPPFLAGS = -I../../inc/foo\ -I../../inc/foo/A \ -I../../inc/bar/ pname_LDADD= foo/libfoo.a bar/libbar.a SUBDIRS = foo bar and in ../src/foo noinst_LIBRARIES = libfoo.a libfoo_a_SOURCES = \ x.cpp \ y.cpp AM_CPPFLAGS = \ -I../../inc/foo \ -I../../inc/foo/A \ -I../../inc/bar And the analogous in src/bar. The problem is that after calling automake and autoconf, when calling "make" the compilation fails. In particular, the program enters the directory src, then foo and creates libfoo.a, but the same fail for libbar.a, with the following error: Making all in bar make[3]: Entering directory `/user/Raffo/project/src/bar' make[3]: *** No rule to make target `all'. Stop. I have read the autotools documentation, but I'm not able to find a similar example to the one I am working on. Unfortunately I can't change the directory structure as this is a fixed requisite of the project I'm working on. I don't know if you can help me or give me any hint, but maybe you can guess the error or give me a link to a similar structured example. Thank you.

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  • help with mysql triggers (checking values before insert)

    - by user332817
    hi I'm quite new to mysql and I'm trying to figure out how to use triggers. what I'm trying to do: I have 2 tables, max and sub_max, when I insert a new row to sub_max I want to check if the SUM of the values with the same foreign_key as the new row are less than the value in the max table. I think this sounds confusing so here are my tables: CREATE TABLE max( number INT , MaxAmount integer NOT NULL) CREATE TABLE sub_max( sub_number INT , sub_MaxAmount integer NOT NULL, number INT, FOREIGN KEY ( number ) REFERENCES max( number )) and here is my code for the trigger, I know the syntax is off but this is the best I could do from looking up tutorials. CREATE TRIGGER maxallowed after insert on submax FOR EACH ROW BEGIN DECLARE submax integer; DECLARE maxmax integer; submax = select sum(sub_MaxAmount) from sub_max where sub_number = new.sub_number; submax = submax + new. sub_MaxAmount; maxmax = select MaxAmount from max where number = new.number ; if max>maxmax rollback? END I wanted to know if I'm doing this remotely correctly. Thanks in advance.

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  • World's Most Challening MySQL SQL Query (least I think so...)

    - by keruilin
    Whoever answers this question can claim credit for solving the world's most challenging SQL query, according to yours truly. Working with 3 tables: users, badges, awards. Relationships: user has many awards; award belongs to user; badge has many awards; award belongs to badge. So badge_id and user_id are foreign keys in the awards table. The business logic at work here is that every time a user wins a badge, he/she receives it as an award. A user can be awarded the same badge multiple times. Each badge is assigned a designated point value (point_value is a field in the badges table). For example, BadgeA can be worth 500 Points, BadgeB 1000 Points, and so on. As further example, let's say UserX won BadgeA 10 times and BadgeB 5 times. BadgeA being worth 500 Points, and BadgeB being worth 1000 Points, UserX has accumulated a total of 10,000 Points ((10 x 500) + (5 x 1000)). The end game here is to return a list of top 50 users who have accumulated the most badge points. Can you do it?

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  • Java client server sending bytes receiver listens indefinitely

    - by Rob
    Hello, I'm trying to write a Java program for Windows that involves communication with a server program located on a foreign machine.My program successfully connects to the server, successfully writes a byte array to it, and waits for a response. I know that the server is printing bytes (the response) back to me one byte at a time. I've tried using a DataInputStream object with various methods (read, readByte etc.), I've tried using a BufferedReader object with its methods (read, readLine etc.) but all the reader objects and various methods that I've used all come up against the same problem. The bytes are being successfully read (each time a byte or bytes are read, I can print them to the console, and they are what I'd expect them to be). The problem is that my reader doesn't know when to stop reading. Even if the server has sent all its bytes, the reader function on my end waits for more data, indefinitely, and so the program hangs at the read function. This problem seems to affect all the techniques that I have tried. I've been running tests with a simple client program and server program, each about 40 or 50 lines long, where the client connects to the server, and sends some bytes to it. All the techniques I've tried for the server reader result in the same problem mentioned above (the server hangs waiting for more input from the client, even though it has sent all its data). I'm really desperate for some help on this. It's important that I get this program finished soon, and it's basically complete except for this communication issue. Any help is much appreciated! -Rob

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  • Weird MySQL behavior, seems like a SQL bug

    - by Daniel Magliola
    I'm getting a very strange behavior in MySQL, which looks like some kind of weird bug. I know it's common to blame the tried and tested tool for one's mistakes, but I've been going around this for a while. I have 2 tables, I, with 2797 records, and C, with 1429. C references I. I want to delete all records in I that are not used by C, so i'm doing: select * from i where id not in (select id_i from c); That returns 0 records, which, given the record counts in each table, is physically impossible. I'm also pretty sure that the query is right, since it's the same type of query i've been using for the last 2 hours to clean up other tables with orphaned records. To make things even weirder... select * from i where id in (select id_i from c); DOES work, and brings me the 1297 records that I do NOT want to delete. So, IN works, but NOT IN doesn't. Even worse: select * from i where id not in ( select i.id from i inner join c ON i.id = c.id_i ); That DOES work, although it should be equivalent to the first query (i'm just trying mad stuff at this point). Alas, I can't use this query to delete, because I'm using the same table i'm deleting from in the subquery. I'm assuming something in my database is corrupt at this point. In case it matters, these are all MyISAM tables without any foreign keys, whatsoever, and I've run the same queries in my dev machine and in the production server with the same result, so whatever corruption there might be survived a mysqldump / source cycle, which sounds awfully strange. Any ideas on what could be going wrong, or, even more importantly, how I can fix/work around this? Thanks! Daniel

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  • updating dataset using join and bindingsource?

    - by netadictos
    Hi, I have created a dataset and in the designer I have created the relations and foreign keys that exist in the database. Basically, I have a product that has a relationship to a table of prices. The keyfield they share is IdProduct in the Prices table. In the Fill/Get of the product I return the Price field. I also have a DataGrid that uses a BindingSource which uses this table. Everything displays correctly and when I double click on a row within the datagrid I then open up a tabbed form that contains a detailed view of the record selected. The user at this point is able to make changes to the record and they are properly propogated back to the BindingSource. The problem is that the TableAdapter does not contain the appopriate update, therefore I am not able to call the TableAdapter.Update method with the dataset as I would had I created a tableadapter not using a join. How am I best to handle this situation. At the same time I cannot get any modified row: dTiendasDs.ProductosDataTable modified = (dTiendasDs.ProductosDataTable) dTiendasDs.Productos.GetChanges(DataRowState.Modified); modified is always null Thanks,

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  • How to check if two records have a self-referencing relation?

    - by Machine
    Consider the following schema with users and their collegues (friends): Users User: columns: user_id: name: user_id as userId type: integer(8) unsigned: 1 primary: true autoincrement: true first_name: name: first_name as firstName type: string(45) notnull: true last_name: name: last_name as lastName type: string(45) notnull: true email: type: string(45) notnull: true unique: true relations: Collegues: class: User local: invitor foreign: invitee refClass: CollegueStatus equal: true onDelete: CASCADE onUpdate: CASCADE Join table: CollegueStatus: columns: invitor: type: integer(8) unsigned: 1 primary: true invitee: type: integer(8) unsigned: 1 primary: true status: type: enum(8) values: [pending, accepted, denied] default: pending notnull: true Now, let's say I two records, one for the user making a HTTP request (the logged in user), and one record for a user he wants to send a message to. I want to check if these users are collegues. Questions: Does Doctrine have any pre-build functionality to check if two records with with self-relations are related? If not, how would you write a method to check this? Where would you put said method? (In the User-class, UserTable-class etc) I could probably do something like this: public function (User $user1, User $user2) { // Ensure we load collegues if $user1 was fetched with DQL that // doesn't load this relation $collegues = $user1->get('Collegues'); $areCollegues = false; foreach($collegues as $collegue) { if($collegue['userId'] === $user2['userId']) { $areCollegues = true; break; } } return $areCollegues; } But this looks a neither efficient nor pretty. I just feel that it should be solved already for self-referencing relations to be nice to use.

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  • Saving tree-structures in Databases

    - by Nina Null
    Hello everyone. I use Hibernate/Spring and a MySQL Database for my data management. Currently I display a tree-structure in a JTable. A tree can have several branches, in turn a branch can have several branches (up to nine levels) again, or having leaves. Lately I have performanceproblemes, as soon as I want to create new branches on deeper levels. At this time a branch has a foreign key to its parent. The domainobject has access to its parent by calling getParent(), which returns the parent-branch. The deeper the level, the longer it takes to create a new branch. Microbenchmark results for creating a new branch are like: Level 1: 32 ms. Level 3: 80 ms. Level 9: 232 ms. Obviously the level (which means the number of parents) is responsible for this. So I wanted to ask, if there are any appendages to work around this kind of problem. I don’t understand why Hibernate needs to know about the whole object tree (all parents until the root) while creating a new branch. But as far as I know this can be the only reason for the delay while creating a new branch, because a branch doesn’t have any other relations to any other objects. I would be very thankful for any workarounds or suggestions. greets, jambusa

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  • How do I relate two models/tables in Django based on non primary non unique keys?

    - by wizard
    I've got two tables that I need to relate on a single field po_num. The data is imported from another source so while I have a little bit of control over what the tables look like but I can't change them too much. What I want to do is relate these two models so I can look up one from the other based on the po_num fields. What I really need to do is join the two tables so I can do a where on a count of the related table. I would like to do filter for all Order objects that have 0 related EDI856 objects. I tried adding a foreign key to the Order model and specified the db_column and to_fields as po_num but django didn't like that the fact that Edi856.po_num wasn't unique. Here are the important fields of my current models that let me display but not filter for the data that I want. class Edi856(models.Model): po_num = models.CharField(max_length=90, db_index=True ) class Order(models.Model): po_num = models.CharField(max_length=90, db_index=True) def in_edi(self): '''Has the edi been processed?''' return Edi856.objects.filter(po_num = self.po_num).count() Thanks for taking the time to read about my problem. I'm not sure what to do from here.

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  • SQLAlchemy Expression Language problem

    - by Torkel
    I'm trying to convert this to something sqlalchemy expression language compatible, I don't know if it's possible out of box and are hoping someone more experienced can help me along. The backend is PostgreSQL and if I can't make it as an expression I'll create a string instead. SELECT DISTINCT date_trunc('month', x.x) as date, COALESCE(b.res1, 0) AS res1, COALESCE(b.res2, 0) AS res2 FROM generate_series( date_trunc('year', now() - interval '1 years'), date_trunc('year', now() + interval '1 years'), interval '1 months' ) AS x LEFT OUTER JOIN( SELECT date_trunc('month', access_datetime) AS when, count(NULLIF(resource_id != 1, TRUE)) AS res1, count(NULLIF(resource_id != 2, TRUE)) AS res2 FROM tracking_entries GROUP BY date_trunc('month', access_datetime) ) AS b ON (date_trunc('month', x.x) = b.when) First of all I got a class TrackingEntry mapped to tracking_entries, the select statement within the outer joined can be converted to something like (pseudocode):: from sqlalchemy.sql import func, select from datetime import datetime, timedelta stmt = select([ func.date_trunc('month', TrackingEntry.resource_id).label('when'), func.count(func.nullif(TrackingEntry.resource_id != 1, True)).label('res1'), func.count(func.nullif(TrackingEntry.resource_id != 2, True)).label('res2') ], group_by=[func.date_trunc('month', TrackingEntry.access_datetime), ]) Considering the outer select statement I have no idea how to build it, my guess is something like: outer = select([ func.distinct(func.date_trunc('month', ?)).label('date'), func.coalesce(?.res1, 0).label('res1'), func.coalesce(?.res2, 0).label('res2') ], from_obj=[ func.generate_series( datetime.now(), datetime.now() + timedelta(days=365), timedelta(days=1) ).label(x) ]) Then I suppose I have to link those statements together without using foreign keys: outer.outerjoin(stmt???).??(func.date_trunc('month', ?.?), ?.when) Anyone got any suggestions or even better a solution?

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  • Process-to-port mapping with SNMP and/or wmi/wmic in java

    - by Niddy888
    I'm trying to use SNMP to map outgoing ports on my host computer with the application running on the computer that is responsible for that communication. When running "netstat -ano" I get access to Protocol, Local Address (with port), Foreign Address (with port), State and PID. But I want to do this entirely without having to execute "cmd" from Java. By using SNMP OID: .1.3.6.1.2.1.25.4 (.iso.org.dod.internet.mgmt.mib-2.host.hrSWRun) I get access to PID (ex. 1704), Name (ex. cmd.exe), Path (ex. C:\Windows\system32) among others. There is an SNMP OID: .1.3.6.1.2.1.6.13 (.iso.org.dod.internet.mgmt.mib-2.tcp.tcpConnTable) that give you access to TCP connection state, local address, local port, remote address, remote port. But NO PID. So to sum up. My question again: Is there a way to "map" these tables together? Either directly in SNMP with other OID's or in conjunction with WMI / WMIC?

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  • table design for storing large number of rows

    - by hyperboreean
    I am trying to store in a postgresql database some unique identifiers along with the site they have been seen on. I can't really decide which of the following 3 option to choose in order to be faster and easy maintainable. The table would have to provide the following information: the unique identifier which unfortunately it's text the sites on which that unique identifier has been seen The amount of data that would have to hold is rather large: there are around 22 millions unique identifiers that I know of. So I thought about the following designs of the table: id - integer identifier - text seen_on_site - an integer, foreign key to a sites table This approach would require around 22 mil multiplied by the number of sites. id - integer identifier - text seen_on_site_1 - boolean seen_on_site_2 - boolean ............ seen_on_site_n - boolean Hopefully the number of sites won't go past 10. This would require only the number of unique identifiers that I know of, that is around 20 millions, but it would make it hard to work with it from an ORM perspective. one table that would store only unique identifiers, like in: id - integer unique_identifier - text, one table that would store only sites, like in: id - integer site - text and one many to many relation, like: id - integer, unique_id - integer (fk to the table storing identifiers) site_id - integer (fk to sites table) another approach would be to have a table that stores unique identifiers for each site So, which one seems like a better approach to take on the long run?

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  • Using Subsonic 3.0 Advanced Templates

    - by umit
    Hi all, I've been trying to use Subsonic Advanced Templates in a project for a while but most of the time I find myself writing a Stored Procedure as I can't find a proper way of doing it in code. Subsonic created corresponding objects for my DB tables and for foreign keys it created IQueryable fields inside each object. These fields are not loaded by default and a new SQL query is executed when you access them. 1- Is there a way to get all data in one query (deep load)? Also these fields can not be assigned. So when I want to create an object in a maintenance page, I can't put all the data into this object before saving it in DB: Post post = new Post(); //get photos for this post IList<PostPhoto> postPhotos = GetPostPhotos(); post.PostPhotos = postPhotos; 2- Is it possible to have one Post object with all fields set from user input? Think of the Post object above and assume I've successfully assigned its fields. Now I need to save it to the DB. 3- Is using BatchQuery the only way to do it in one query? If I have 4 photos in PostPhotos field; 2 of them previously saved and 2 of them new, can I use the Update method to handle both the adding and updating of these photos? Any ideas or links are appreciated. Cheers...

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  • Wnat is the preferred method of building extremely lightweight business object / DAL now that I have

    - by Seth Spearman
    Hello, I have completed a simple database for a project. Only 6tables. Of the 6, one is a "lookup" table. There is one "master" table that is the driver for the system. It is referenced as a foreign key by the other four tables. Give that this step is completed. What is the FASTEST, EASIEST way to create POCOs/BizObjects that can load load the data and the child data. Here are my CAVEATS. *I don't want to spend more than 30-60 minutes learning how? *There is very little biz logic needed in the POCOs. They will pretty much load data. Don't even really need to write back data. *I already know CSLA (up to version 3) but I feel that is overkill for this little project. *Nevertheless, I would love it if it ROOT objects could have collection classes that contain the CHILD objects as in CSLA...but again, without using CSLA. *Please give the answer for .NET 35 but also if I was restricted to only use .NET 20. *Ideally I could just point a tool at the database and the POCOs would be genn'ed. *FREE Just curious what you guys use for this kind of scenario. I understand that this question is subjective but I want to hear a variety of answers. Seth

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  • Heavy Mysql operation & Time Constraints [closed]

    - by Rahul Jha
    There is a performance issue where that I have stuck with my application which is based on PHP & MySql. The application is for Data Migration where data has to be uploaded and after various processes (Cleaning from foreign characters, duplicate check, id generation) it has to be inserted into one central table and then to 5 different tables. There, an id is generated and that id has to be updated to central table. There are different sets of records and validation rules. The problem I am facing is that when I insert say(4K) rows file (containing 20 columns) it is working fine within 15 min it gets inserted everywhere. But, when I insert the same records again then at this time it is taking one hour to insert (ideally it should get inserted by marking earlier inserted data as duplicate). After going through the log file, I noticed is that there is a Mysql select statement where I am checking the duplicates and getting ID which are duplicates. Then I am calling a function inside for loop which is basically inserting records into 5 tables and updates id to central table. This Calling function is major time of whole process. P.S. The records has to be inserted record by record.. Kindly Suggest some solution.. //This is that sample code $query=mysql_query("SELECT DISTINCT p1.ID FROM table1 p1, table2 p2, table3 a WHERE p2.datatype =0 AND (p1.datatype =1 || p1.datatype=2) AND p2.ID =0 AND p1.ID = a.ID AND p1.coulmn1 = p2.column1 AND p1.coulmn2 = p2.coulmn2 AND a.coulmn3 = p2.column3"); $num=mysql_num_rows($query); for($i=0;$i<$num;$i++) { $f=mysql_result($query,$i,"ID"); //calling function RecordInsert($f); }

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  • JSP/Struts2/Hibernate: loop through a self-referencing table.

    - by TBW
    Hello everyone, Let's say we have a self-referencing table called PERSON, with the following columns: ID, PARENT, where PARENT is a foreign key to the ID column of another element in the PERSON table. Of course, many persons can have the same parent. I use Hibernate 3 in lazy fetching mode to deal with the database. Hibernate fetches a person element from the database, which is then put in the ValueStack by the Struts2 action, to be used on the result JSP page. Now the question is : In JSP, how can I do to display all the child (and the child's child, and so on, like a family tree) of this person element? Of course, for the n+1 children I can use the < s:iterator tag over the person.person. I can also nest another < s:iterator tag over person.person.person to get the n+2 children. But what if I want to do this in an automated manner, up to the last n+p child, displaying in the process all the children of all the n+1..n+p elements? I hope I have been clear enough. Thank you all for your time. -- TBW.

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  • Detaching all entities of T to get fresh data

    - by Goran
    Lets take an example where there are two type of entites loaded: Product and Category, Product.CategoryId - Category.Id. We have available CRUD operations on products (not Categories). If on another screen Categories are updated (or from another user in the network), we would like to be able to reload the Categories, while preserving the context we currently use, since we could be in the middle of editing data, and we do not want changes to be lost (and we cannot depend on saving, since we have incomplete data). Since there is no easy way to tell EF to get fresh data (added, removed and modified), we thought of twp possible ways: 1) Getting products attached to context, and categories detached from context. This would mean that we loose the ability to access Product.Category.Name, which we do sometimes require, so we would need to manually resolve it (example when printing data). 2) detaching / attaching all Categories from current context. Context.ChangeTracker.Entries().Where(x => x.Entity.GetType() == typeof(T)).ForEach(x => x.State = EntityState.Detached); And then reload the categories, which will get fresh data. Do you find any problem with this second approach? We understand that this will require all constraints to be put on foreign keys, and not navigation properties, since when detaching all Categories, Product.Category navigation properties would be reset to null also. Also, there could be a potential performance problem, which we did not test, since there could be couple of thousand products loaded, and all would need to resolve navigation property when reloading. Which of the two do you prefer, and is there a better way (EF6 + .NET 4.0)?

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  • Hi, how can I use the check box group in JSF to select the items of database and generate a list in

    - by Alexzzy
    I am using netbean and JSF to do my project, recently I encountered a problem that confused me. The question: There is a set of check box groups that identify the artifacts from the nature, creator, period and school. And all the artifacts are stored in a table of database. I would like to select the items by nature or creator or something like that, and generate a list for the items selected in the next page. There are some tables of database for artifacts, nature, creators and school, and the type_ID(this is the nature), creator_ID, school_ID are the foreign keys in artifacts table. I have bound the tables with respective check boxes. For example, if I want to select nature is painting, creator is Davinci, school is Italian Renaissance, and then I click Search button. It will go to next page that generate a list of artifacts about all Italian Renaissance paintings created by Davinci. How can I do that? I was confused by JSF, but I have to use JSF to do my project. Anyone can help me plz??? Thank you very very much !!!!!!!

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  • [CODE GENERATION] How to generate DELETE statements in PL/SQL, based on the tables FK relations?

    - by The chicken in the kitchen
    Is it possible via script/tool to generate authomatically many delete statements based on the tables fk relations, using Oracle PL/SQL? In example: I have the table: CHICKEN (CHICKEN_CODE NUMBER) and there are 30 tables with fk references to its CHICKEN_CODE that I need to delete; there are also other 150 tables foreign-key-linked to that 30 tables that I need to delete first. Is there some tool/script PL/SQL that I can run in order to generate all the necessary delete statements based on the FK relations for me? (by the way, I know about cascade delete on the relations, but please pay attention: I CAN'T USE IT IN MY PRODUCTION DATABASE, because it's dangerous!) I'm using Oracle DataBase 10G R2. This is the result I've written, but it is not recursive: This is a view I have previously written, but of course it is not recursive! CREATE OR REPLACE FORCE VIEW RUN ( OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME, VINCOLO ) AS SELECT OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME, '(' || LTRIM ( EXTRACT (XMLAGG (XMLELEMENT ("x", ',' || COLUMN_NAME)), '/x/text()'), ',') || ')' VINCOLO FROM ( SELECT CON1.OWNER OWNER_1, CON1.TABLE_NAME TABLE_NAME_1, CON1.CONSTRAINT_NAME CONSTRAINT_NAME_1, CON1.DELETE_RULE, CON1.STATUS, CON.TABLE_NAME, CON.CONSTRAINT_NAME, COL.POSITION, COL.COLUMN_NAME FROM DBA_CONSTRAINTS CON, DBA_CONS_COLUMNS COL, DBA_CONSTRAINTS CON1 WHERE CON.OWNER = 'TABLE_OWNER' AND CON.TABLE_NAME = 'TABLE_OWNED' AND ( (CON.CONSTRAINT_TYPE = 'P') OR (CON.CONSTRAINT_TYPE = 'U')) AND COL.TABLE_NAME = CON1.TABLE_NAME AND COL.CONSTRAINT_NAME = CON1.CONSTRAINT_NAME --AND CON1.OWNER = CON.OWNER AND CON1.R_CONSTRAINT_NAME = CON.CONSTRAINT_NAME AND CON1.CONSTRAINT_TYPE = 'R' GROUP BY CON1.OWNER, CON1.TABLE_NAME, CON1.CONSTRAINT_NAME, CON1.DELETE_RULE, CON1.STATUS, CON.TABLE_NAME, CON.CONSTRAINT_NAME, COL.POSITION, COL.COLUMN_NAME) GROUP BY OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME; ... and it contains the error of using DBA_CONSTRAINTS instead of ALL_CONSTRAINTS...

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  • Self referencing update SQL statement for Informix

    - by CheeseConQueso
    Need some Informix SQL... Courses get a regular grade, but their associated labs get a grade of 'LAB'. I need to update the table so that the lab grade matches the course grade. Also, if there is no corresponding course for a lab, it means the course was canceled. In that case, I want to place a flag value of 'X' for its grade. Example data before update: id yr sess crs_no hrs grd 725 2009 FA COLL101 3.000000000000 C 725 2009 FA ENGL021 3.000000000000 FI 725 2009 FA ENGL021L 1.000000000000 LAB 725 2009 FA ENGL031 3.000000000000 FNI 725 2009 FA ENGL031L 1.000000000000 LAB 725 2009 FA MATH010 3.000000000000 FNI 725 2010 SP AOTE101 3.000000000000 C 725 2010 SP ENGL021L 1.000000000000 LAB 725 2010 SP ENGL031 3.000000000000 FI 725 2010 SP ENGL031L 1.000000000000 LAB 725 2010 SP MATH010 3.000000000000 FNI 726 2010 SP SPAN101 3.000000000000 FN Example data after update: id yr sess crs_no hrs grd 725 2009 FA COLL101 3.000000000000 C 725 2009 FA ENGL021 3.000000000000 FI 725 2009 FA ENGL021L 1.000000000000 FI 725 2009 FA ENGL031 3.000000000000 FNI 725 2009 FA ENGL031L 1.000000000000 FNI 725 2009 FA MATH010 3.000000000000 FNI 725 2010 SP AOTE101 3.000000000000 C 725 2010 SP ENGL021L 1.000000000000 X 725 2010 SP ENGL031 3.000000000000 FI 725 2010 SP ENGL031L 1.000000000000 FI 725 2010 SP MATH010 3.000000000000 FNI 726 2010 SP SPAN101 3.000000000000 FN I worked out a solution for this, but it required a lot of on-the-fly composite foreign keys built from concatenating the id, yr, sess, and substring'd crs_no. My solution is not only overkill, but it has gaps in it and it takes too long to process. I know there is an easier way to do this, but I've gone so far down one road that I am having trouble thinking of a different approach.

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  • Excessive use of Inner Join for more than 3 tables

    - by Archangel08
    Good Day, I have 4 tables on my DB (not the actual name but almost similar) which are the ff: employee,education,employment_history,referrence employee_id is the name of the foreign key from employee table. Here's the example (not actual) data: **Employee** ID Name Birthday Gender Email 1 John Smith 08-15-2014 Male [email protected] 2 Jane Doe 00-00-0000 Female [email protected] 3 John Doe 00-00-0000 Male [email protected] **Education** Employee_ID Primary Secondary Vocation 1 Westside School Westshore H.S SouthernBay College 2 Eastside School Eastshore H.S NorthernBay College 3 Northern School SouthernShore H.S WesternBay College **Employment_History** Employee_ID WorkOne StartDate Enddate 1 StarBean Cafe 12-31-2012 01-01-2013 2 Coffebucks Cafe 11-01-2012 11-02-2012 3 Latte Cafe 01-02-2013 04-05-2013 Referrence Employee_ID ReferrenceOne Address Contact 1 Abraham Lincoln Lincoln Memorial 0000000000 2 Frankie N. Stein Thunder St. 0000000000 3 Peter D. Pan Neverland Ave. 0000000000 NOTE: I've only included few columns though the rest are part of the query. And below are the codes I've been working on for 3 consecutive days: $sql=mysql_query("SELECT emp.id,emp.name,emp.birthday,emp.pob,emp.gender,emp.civil,emp.email,emp.contact,emp.address,emp.paddress,emp.citizenship,educ.employee_id,educ.elementary,educ.egrad,educ.highschool,educ.hgrad,educ.vocational,educ.vgrad,ems.employee_id,ems.workOne,ems.estartDate,ems.eendDate,ems.workTwo,ems.wstartDate,ems.wendDate,ems.workThree,ems.hstartDate,ems.hendDate FROM employee AS emp INNER JOIN education AS educ ON educ.employee_id='emp.id' INNER JOIN employment_history AS ems ON ems.employee_id='emp.id' INNER JOIN referrence AS ref ON ref.employee_id='emp.id' WHERE emp.id='$id'"); Is it okay to use INNER JOIN this way? Or should I modify my query to get the results that I wanted? I've also tried to use LEFT JOIN but still it doesn't return anything .I didn't know where did I go wrong. You see, as I have thought, I've been using the INNER JOIN in correct manner, (since it was placed before the WHILE CLAUSE). So I couldn't think of what could've possible went wrong. Do you guys have a suggestion? Thanks in advance.

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  • How to structure the tables of a very simple blog in MySQL?

    - by Programmer
    I want to add a very simple blog feature on one of my existing LAMP sites. It would be tied to a user's existing profile, and they would be able to simply input a title and a body for each post in their blog, and the date would be automatically set upon submission. They would be allowed to edit and delete any blog post and title at any time. The blog would be displayed from most recent to oldest, perhaps 20 posts to a page, with proper pagination above that. Other users would be able to leave comments on each post, which the blog owner would be allowed to delete, but not pre-moderate. That's basically it. Like I said, very simple. How should I structure the MySQL tables for this? I'm assuming that since there will be blog posts and comments, I would need a separate table for each, is that correct? But then what columns would I need in each table, what data structures should I use, and how should I link the two tables together (e.g. any foreign keys)? I could not find any tutorials for something like this, and what I'm looking to do is really offer my users the simplest version of a blog possible. No tags, no moderation, no images, no fancy formatting, etc. Just a simple diary-type, pure-text blog with commenting by other users.

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