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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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• Hibernate MapKeyManyToMany gives composite key where none exists

  - by larsrc

  I have a Hibernate (3.3.1) mapping of a map using a three-way join table: @Entity public class SiteConfiguration extends ConfigurationSet { @ManyToMany @MapKeyManyToMany(joinColumns=@JoinColumn(name="SiteTypeInstallationId")) @JoinTable( name="SiteConfig_InstConfig", joinColumns = @JoinColumn(name="SiteConfigId"), inverseJoinColumns = @JoinColumn(name="InstallationConfigId") ) Map<SiteTypeInstallation, InstallationConfiguration> installationConfigurations = new HashMap<SiteTypeInstallation, InstallationConfiguration>(); ... } The underlying table (in Oracle 11g) is: Name Null Type ------------------------------ -------- ---------- SITECONFIGID NOT NULL NUMBER(19) SITETYPEINSTALLATIONID NOT NULL NUMBER(19) INSTALLATIONCONFIGID NOT NULL NUMBER(19) The key entity used to have a three-column primary key in the database, but is now redefined as: @Entity public class SiteTypeInstallation implements IdResolvable { @Id @GeneratedValue(generator="SiteTypeInstallationSeq", strategy= GenerationType.SEQUENCE) @SequenceGenerator(name = "SiteTypeInstallationSeq", sequenceName = "SEQ_SiteTypeInstallation", allocationSize = 1) long id; @ManyToOne @JoinColumn(name="SiteTypeId") SiteType siteType; @ManyToOne @JoinColumn(name="InstalationRoleId") InstallationRole role; @ManyToOne @JoinColumn(name="InstallationTypeId") InstType type; ... } The table for this has a primary key 'Id' and foreign key constraints+indexes for each of the other columns: Name Null Type ------------------------------ -------- ---------- SITETYPEID NOT NULL NUMBER(19) INSTALLATIONROLEID NOT NULL NUMBER(19) INSTALLATIONTYPEID NOT NULL NUMBER(19) ID NOT NULL NUMBER(19) For some reason, Hibernate thinks the key of the map is composite, even though it isn't, and gives me this error: org.hibernate.MappingException: Foreign key (FK1A241BE195C69C8:SiteConfig_InstConfig [SiteTypeInstallationId])) must have same number of columns as the referenced primary key (SiteTypeInstallation [SiteTypeId,InstallationRoleId]) If I remove the annotations on installationConfigurations and make it transient, the error disappears. I am very confused why it thinks SiteTypeInstallation has a composite key at all when @Id is clearly defining a simple key, and doubly confused why it picks exactly just those two columns. Any idea why this happens? Is it possible that JBoss (5.0 EAP) + Hibernate somehow remembers a mistaken idea of the primary key across server restarts and code redeployments? Thanks in advance, -Lars

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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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• SQLDeveloper using over 100MB of PGA+UGA

  - by Leigh Riffel

  Perhaps this is normal, but in my Oracle 11g database I am seeing programmers using Oracle's SQL Developer regularly consume more than 100MB of combined UGA and PGA memory. I'd like to know if this is normal and what can be done about it. Our database is on the 32 bit version of Windows 2008, so memory limitations are becoming an increasing concern. I am using the following query to show the memory usage: SELECT e.SID, e.username, e.status, b.PGA_MEMORY FROM v$session e LEFT JOIN (select y.SID, y.value pga, TO_CHAR(ROUND(y.value/1024/1024),99999999) || ' MB' PGA_MEMORY from v$sesstat y, v$statname z where y.STATISTIC# = z.STATISTIC# and NAME = 'session pga memory') b ON e.sid=b.sid WHERE (PGA)/1024/1024 > 20 ORDER BY 4 DESC; It seems that the resource usage goes up any time a table is opened in SQLDeveloper, but even when it is closed the memory does not go away. The problem is worse if the table is sorted while it was open as that seems to use even more memory. I understand how this would use memory while it is sorting, and perhaps even while it is still open, but to use memory after it is closed seems wrong to me. Can anyone confirm this? Update: I discovered that my numbers were off due to not understanding that the UGA is stored in the PGA under dedicated server mode. This makes the numbers lower than they were, but the problem still remains that SQL Developer seems to use excessive PGA.

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• Replacing a word in a text file with a value using python

  - by Jamde Jam

  I have been trying to replace a word in a text file with a value (say 1), but my outfile is blank.I am new to python (its only been a month since I have been learning it). My file is relatively large, but I just want to replace a word with the value 1 for now. Here is a segment of what the file looks like: NAME SECOND_1 ATOM 1 6 0 0 0 # ORB 1 ATOM 2 2 0 12/24 0 # ORB 2 ATOM 3 2 12/24 0 0 # ORB 2 ATOM 4 2 0 0 4/24 # ORB 3 ATOM 5 2 0 0 20/24 # ORB 3 ATOM 6 2 0 0 8/24 # ORB 3 ATOM 7 2 0 0 16/24 # ORB 3 ATOM 8 6 0 0 12/24 # ORB 1 ATOM 9 2 12/24 0 12/24 # ORB 2 ATOM 10 2 0 12/24 12/24 # ORB 2 #1 #2 #3 I want to first replace the word ATOM with the value 1. Next I want to replace #ORB with a space. Here is what I am trying thus far. input = open('SECOND_orbitsJ22.txt','r') output=open('SECOND_orbitsJ22_out.txt','w') for line in input: word=line.split(',') if(word[0]=='ATOM'): word[0]='1' output.write(','.join(word)) Can anyone offer any suggestions or help? Thanks so much.

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• JoinColumn name not used in sql

  - by Vladimir

  Hi! I have a problem with mapping many-to-one relationship without exact foreign key constraint set in database. I use OpenJPA implementation with MySql database, but the problem is with generated sql scripts for insert and select statements. I have LegalEntity table which contains RootId column (among others). I also have Address table which has LegalEntityId column which is not nullable, and which should contain values referencing LegalEntity's "RootId" column, but without any database constraint (foreign key) set. Address entity is mapped: @Entity @Table(name="address") public class Address implements Serializable { ... @ManyToOne(fetch=FetchType.LAZY, optional=false) @JoinColumn(referencedColumnName="RootId", name="LegalEntityId", nullable=false, insertable=true, updatable=true, table="LegalEntity") public LegalEntity getLegalEntity() { return this.legalEntity; } } SELECT statement (when fetching LegalEntity's addresses) and INSERT statment are generated: SELECT t0.Id, .., t0.LEGALENTITY_ID FROM address t0 WHERE t0.LEGALENTITY_ID = ? ORDER BY t0.Id DESC [params=(int) 2] INSERT INTO address (..., LEGALENTITY_ID) VALUES (..., ?) [params=..., (int) 2] If I omit table attribute from mentioned statements are generated: SELECT t0.Id, ... FROM address t0 INNER JOIN legalentity t1 ON t0.LegalEntityId = t1.RootId WHERE t1.Id = ? ORDER BY t0.Id DESC [params=(int) 2] INSERT INTO address (...) VALUES (...) [params=...] So, LegalEntityId is not included in any of the statements. Is it possible to have relationship based on such referencing (to column other than primary key, without foreign key in database)? Is there something else missing? Thanks in advance.

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• How can I optimize the SELECT statement running on an Oracle database?

  - by Elvis Lou

  I have a SELECT statement in ORACLE: SELECT COUNT(DISTINCT ds1.endpoint_msisdn) multiple30, dss1.service, dss1.endpoint_provisioning_id, dss1.company_scope, Nvl(x.subscription_status, dss1.subscription_status) subscription_status FROM daily_summary ds1 join daily_summary ds2 ON ds1.endpoint_msisdn = ds2.endpoint_msisdn, daily_summary_static dss1, daily_summary_static dss2, (SELECT NULL subscription_status FROM dual UNION ALL SELECT -2 subscription_status FROM dual) x WHERE ds1.summary_ts >= To_date('10-04-2012', 'dd-mm-yyyy') - 30 AND ds1.summary_ts <= To_date('10-04-2012', 'dd-mm-yyyy') AND dss1.last_active >= To_date('10-04-2012', 'dd-mm-yyyy') - 30 AND dss1.last_active <= To_date('10-04-2012', 'dd-mm-yyyy') AND dss2.last_active >= To_date('10-04-2012', 'dd-mm-yyyy') - 30 AND dss2.last_active <= To_date('10-04-2012', 'dd-mm-yyyy') AND dss1.service <> dss2.service AND ( dss1.company_scope = 2 OR dss1.company_scope = 5 ) AND ( dss2.company_scope = 2 OR dss2.company_scope = 5 ) AND dss1.company_scope = dss2.company_scope AND ds1.endpoint_noc_id = dss1.endpoint_noc_id AND ds1.endpoint_host_id = dss1.endpoint_host_id AND ds1.endpoint_instance_id = dss1.endpoint_instance_id AND ds2.endpoint_noc_id = dss2.endpoint_noc_id AND ds2.endpoint_host_id = dss2.endpoint_host_id AND ds2.endpoint_instance_id = dss2.endpoint_instance_id AND dss1.endpoint_provisioning_id = dss2.endpoint_provisioning_id AND Least(1, ds1.total_actions) = 1 AND Least(1, ds2.total_actions) = 1 GROUP BY dss1.service, dss1.endpoint_provisioning_id, dss1.company_scope, Nvl(x.subscription_status, dss1.subscription_status); This query took about 26 minutes to return in my environment, but if I remove the section: dss1.last_active >= to_date('10-04-2012','dd-mm-yyyy') - 30 AND dss1.last_active <= to_date('10-04-2012','dd-mm-yyyy') AND dss2.last_active >= to_date('10-04-2012','dd-mm-yyyy') - 30 AND dss2.last_active <= to_date('10-04-2012','dd-mm-yyyy') AND it only took 20 seconds to run. We have index on the column last_active, I don't know why the section slow down the performance so much? any ideas?

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• How can I perform this query between related tables without using UNION?

  - by jeremy

  Suppose I have two separate tables that I watch to query. Both of these tables has a relation with a third table. How can I query both tables with a single, non UNION based query? I want the result of the search to rank the results by comparing a field on each table. Here's a theoretical example. I have a User table. That User can have both CDs and books. I want to find all of that user's books and CDs with a single query matching a string ("awesome" in this example). A UNION based query might look like this: SELECT "book" AS model, name, ranking FROM book WHERE name LIKE 'Awesome%' UNION SELECT "cd" AS model, name, ranking FROM cd WHERE name LIKE 'Awesome%' ORDER BY ranking DESC How can I perform a query like this without the UNION? If I do a simple left join from User to Books and CDs, we end up with a total number of results equal to the number of matching cds timse the number of matching books. Is there a GROUP BY or some other way of writing the query to fix this?

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• JPA concatenating table names for parent/child @OneToMany

  - by Robert

  We are trying to use a basic @OneToMany relationship: @Entity @Table(name = "PARENT_MESSAGE") public class ParentMessage { @Id @Column(name = "PARENT_ID") @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer parentId; @OneToMany(fetch=FetchType.LAZY) private List childMessages; public List getChildMessages() { return this.childMessages; } ... } @Entity @Table(name = "CHILD_MSG_USER_MAP") public class ChildMessage { @Id @Column(name = "CHILD_ID") @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer childId; @ManyToOne(optional=false,targetEntity=ParentMessage.class,cascade={CascadeType.REFRESH}, fetch=FetchType.LAZY) private ParentMessage parentMsg; public ParentMessage getParentMsg() { return parentMsg; } ... } ChildMessage child = new ChildMessage(); em.getTransaction().begin(); ParentMessage parentMessage = (ParentMessage) em.find(ParentMessage.class, parentId); child.setParentMsg(parentMessage); List list = parentMessage.getChildMessages(); if(list == null) list = new ArrayList(); list.add(child); em.getTransaction().commit(); We receive the following error. Why is OpenJPA concatenating the table names to APP.PARENT_MESSAGE_CHILD_MSG_USER_MAP? Of course that table doesn't exist.. the tables defined are APP.PARENT_MESSAGE and APP.CHILD_MSG_USER_MAP Caused by: org.apache.openjpa.lib.jdbc.ReportingSQLException: Table/View 'APP.PARENT_MESSAGE_CHILD_MSG_USER_MAP' does not exist. {SELECT t1.CHILD_ID, t1.PARENT_ID, t1.CREATED_TIME, t1.USER_ID FROM APP.PARENT_MESSAGE_CHILD_MSG_USER_MAP t0 INNER JOIN APP.CHILD_MSG_USER_MAP t1 ON t0.CHILDMESSAGES_CHILD_ID = t1.CHILD_ID WHERE t0.PARENTMESSAGE_PARENT_ID = ?} [code=30000, state=42X05]

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• How do I establish table association in JPA / Hibernate with existing database?

  - by Paperino

  Currently I have two tables in my database Encounters and Referrals: There is a one to many relationship between these two tables. Currently they are linked together with foreign keys. Right now I have public class Encounter extends JPASupport implements java.io.Serializable { @Column(name="referralid", unique=false, nullable=true, insertable=true, updatable=true) public Integer referralid; } But what I really want is public class Encounter extends JPASupport implements java.io.Serializable { .......... @OneToMany(cascade=CascadeType.PERSIST) public Set<Referrals> referral; ............ } So that I can eventually do a query like this: List<Encounter> cases = Encounter.find( "select distinct p from Encounter p join p.referrals as t where t.caseid =103" ).fetch(); How do I tell JPA that even though I have non-standard column names for my foreign keys and primary keys that its the object models that I want linked, not simply the integer value for the keys? Does this make sense? I hope so. Thanks in advanced!

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• Nhibernate - getting single column from other table

  - by Muhammad Akhtar

  I have following tables Employee: ID,CompanyID,Name //CompanyID is foriegn key of Company Table Company: CompanyID, Name I want to map this to the following class: public class Employee { public virtual Int ID { get; set; } public virtual Int CompanyID { get; set; } public virtual string Name { get; set; } public virtual string CompanyName { get; set; } protected Employee() { } } here is my xml class <class name="Employee" table="Employee" lazy="true"> <id name="Id" type="Int32" column="Id"> <generator class="native" /> </id> <property name="CompanyID" column="CompanyID" type="Int32" not-null="false"/> <property name="Name" column="Name" type="String" length="100" not-null="false"/> What I need to add in xml class to map CompanyName in my result? here is my code... public ArrayList getTest() { ISession session = NHibernateHelper.GetCurrentSession(); string query = "select Employee.*,(Company.Name)CompanyName from Employee inner join Employee on Employee.CompanyID = Company.CompanyID"; ArrayList document = (ArrayList)session.CreateSQLQuery(query, "Employee", typeof(Document)).List(); return document; } but in the returned result, I am getting CompanyName is null is result set and other columns are fine. Note:In DB, tables don't physical relation Please suggest my solution ------ Thanks

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• PHP Commercial Project Function define

  - by Shiro

  Currently I am working with a commercial project with PHP. I think this question not really apply to PHP for all programming language, just want to discuss how your guys solve it. I work in MVC framework (CodeIgniter). all the database transaction code in model class. Previously, I seperate different search criteria with different function name. Just an example function get_student_detail_by_ID($id){} function get_student_detail_by_name($name){} as you can see the function actually can merge to one, just add a parameter for it. But something you are rushing with project, you won't look back previously got what similar function just make some changes can meet the goal. In this case, we found that there is a lot function there and hard to maintenance. Recently, we try to group the entity to one ultimate search something like this function get_ResList($is_row_count=FALSE, $record_start=0, $arr_search_criteria='', $paging_limit=20, $orderby='name', $sortdir='ASC') we try to make this function to fit all the searching criteria. However, our system getting bigger and bigger, the search criteria not more 1-2 tables. It require join with other table with different purpose. What we had done is using IF ELSE, if(bla bla bla) { $sql_join = JOIN_SOME_TABLE; $sql_where = CONDITION; } at the end, we found that very hard to maintance the function. it is very hard to debug as well. I would like to ask your opinion, what is the commercial solution they solve this kind of issue, how to define a function and how to revise it. I think this is link project management skill. Hope you willing to share with us. Thanks.

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• How to determine one to many column name from entity type

  - by snicker

  I need a way to determine the name of the column used by NHibernate to join one-to-many collections from the collected entity's type. I need to be able to determine this at runtime. Here is an example: I have some entities: namespace Entities { public class Stable { public virtual int Id {get; set;} public virtual string StableName {get; set;} public virtual IList<Pony> Ponies { get; set; } } public class Dude { public virtual int Id { get; set; } public virtual string DudesName { get; set; } public virtual IList<Pony> PoniesThatBelongToDude { get; set; } } public class Pony { public virtual int Id {get; set;} public virtual string Name {get; set;} public virtual string Color { get; set; } } } I am using NHibernate to generate the database schema, which comes out looking like this: create table "Stable" (Id integer, StableName TEXT, primary key (Id)) create table "Dude" (Id integer, DudesName TEXT, primary key (Id)) create table "Pony" (Id integer, Name TEXT, Color TEXT, Stable_id INTEGER, Dude_id INTEGER, primary key (Id)) Given that I have a Pony entity in my code, I need to be able to find out: A. Does Pony even belong to a collection in the mapping? B. If it does, what are the column names in the database table that pertain to collections In the above instance, I would like to see that Pony has two collection columns, Stable_id and Dude_id.

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• Getting started with open source

  - by lola

  Hi all, I'm an undergraduate who has decided that he wants to join the open source community and contribute. However, I have come to think that, once you have chosen an open source project, a lot of time is spent in learning the nitty gritties of that project in addition to stuff like subversion,etc which a typical undergraduate isn't exposed to. So, you have to stick with that project for a long time, say a year or two, before moving on to other projects. In this case, choosing the right(for you) initial project is very important since if you choose one,and say, the development in your field of interest(in that project) is a low priority and not exciting enough, you'll lose interest and stop contributing to open source all together. So what I wanted to know was, since there are thousands of open source projects, is all this being documented somewhere with tags,etc so that a beginner can choose his projects. The GSoc 2010 ideas list is a great starting point, but it only covers a handful. Hence, I thought why not ask this at stackoverflow: if you have any pointers as to where to start, when choosing a FOSS project or any other tips related to starting with FOSS. P.S. I'm interested in projects involving mobile ad hoc networks(those using TinyOS, preferably), so pointers related to these will be great. I'm looking through Freifunk and OLPC as of now, needed more ideas.

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• error invoking store procedure with input parameter from ADO.Net

  - by George2

  Hello everyone, I am using VSTS 2008 + C# + .Net 3.5 + ADO.Net. Here is my code and related error message. The error message says, @Param1 is not supplied, but actually it is supplied in my code. Any ideas what is wrong? System.Data.SqlClient.SqlException: Procedure or function 'Pr_Foo' expects parameter '@Param1', which was not supplied. class Program { private static SqlCommand _command; private static SqlConnection connection; private static readonly string _storedProcedureName = "Pr_Foo"; private static readonly string connectionString = "server=.;integrated Security=sspi;initial catalog=FooDB"; public static void Prepare() { connection = new SqlConnection(connectionString); connection.Open(); _command = connection.CreateCommand(); _command.CommandText = _storedProcedureName; _command.CommandType = CommandType.StoredProcedure; } public static void Dispose() { connection.Close(); } public static void Run() { try { SqlParameter Param1 = _command.Parameters.Add("@Param1", SqlDbType.Int, 300101); Param1.Direction = ParameterDirection.Input; SqlParameter Param2 = _command.Parameters.Add("@Param2", SqlDbType.Int, 100); portal_SiteInfoID.Direction = ParameterDirection.Input; SqlParameter Param3 = _command.Parameters.Add("@Param3", SqlDbType.Int, 200); portal_RoleInfoID.Direction = ParameterDirection.Input; _command.ExecuteScalar(); } catch (Exception e) { Console.WriteLine(e); } } static void Main(string[] args) { try { Prepare(); Thread t1 = new Thread(Program.Run); t1.Start(); t1.Join(); Dispose(); } catch (Exception ex) { Console.WriteLine(ex.Message + "\t" + ex.StackTrace); } } } thanks in avdance, George

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• Rails - Scalable calculation model

  - by H O

  I currently have a calculation structure in my rails app that has models metric, operand and operation_type. Presently, the metric model has many operands, and can perform calculations based on the operation_type (e.g. sum, multiply, etc.), and each operand is defined as being right or left (i.e. so that if the operation is division, the numerator and denominator can be identified). Presently, an operand is always an attribute of some model, e.g. @customer.sales.selling_price.sum. In order to make this scalable, in need to allow an operand to be either an attribute of some kind, or the results of a previous operation, i.e. an operand can be a metric. I have included a diagram of how my models currently look: Can anyone assist me with the most elegant way of allowing an operand to be an actual operand, or another metric? Thanks! EDIT: It seems based on the only answer so far that perhaps polymorphic associations are the way to go on this, but the answer is so brief I have no idea how they could be used in this way - can anyone elaborate? EDIT 2: OK, I think I'm getting somewhere - essentially i presently have a metric, which has_many operands, and an operand has_many metrics. I need a polymorphic self join, where a metric can also have many metrics - do I need to call this something else, perhaps calculated_metrics, so that the metric model can use itself? That would leave me with a situation where a metric has_many operands, and a metric has many calculated_metrics.

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• Which database I can used and relationship in it ??

  - by mimo-hamad

  My projece make me confused which I didn't find clear things that make me understand the required database and the relationships in it So, would a super one help me to solve it ?!! ;D this is required: 1) Model the data stored in the database (Identify the entities, roles, relationships, constraints, etc.) 2) Write the Oracle commands to create the database, find appropriate data, and populate the database 3) Write five different queries on your database, using the SELECT/FROM/WHERE construct provided in SQL. Your five queries should illustrate several different aspects of database querying, such as: a. Queries over more than one relation (by listing more than one relation in the FROM clause) b. Queries involving aggregate functions, such as SUM, COUNT, and AVG c. Queries involving complicated selects and joins d. Queries involving GROUP BY, HAVING or other similar functions. e. Queries that require the use of the DISTINCT keyword. And this the condition that we need to determine it to solve the required Q's above : 5) It is desired to develop an Internet membership club to buy products at special prices online. To join, new members must be referred by another existing member of the club. The system will keep the following information for each member: The member ID, referring member, birth date, member name, address, phone, mobile, credit card type, number and expiration date. The items are always shipped to the member's address noted in the membership application. The shipping fees will differ for each order.For each item to be requested, the member will select an item from a long list of possible items. For each item in the database, we store an item ID, an item name, description, and list price. The list price will be different from the actual sale price. The available quantity and the back-ordered quantity (the back-ordered quantity is the quantity on-order by the club from its suppliers) is also noted

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• Django - foreignkey problem

  - by realshadow

  Hey, Imagine you have this model: class Category(models.Model): node_id = models.IntegerField(primary_key = True) type_id = models.IntegerField(max_length = 20) parent_id = models.IntegerField(max_length = 20) sort_order = models.IntegerField(max_length = 20) name = models.CharField(max_length = 45) lft = models.IntegerField(max_length = 20) rgt = models.IntegerField(max_length = 20) depth = models.IntegerField(max_length = 20) added_on = models.DateTimeField(auto_now = True) updated_on = models.DateTimeField(auto_now = True) status = models.IntegerField(max_length = 20) node = models.ForeignKey(Category_info, verbose_name = 'Category_info', to_field = 'node_id' The important part is the foreignkey. When I try: Category.objects.filter(type_id = type_g.type_id, parent_id = offset, status = 1) I get an error that get returned more than category, which is fine, because it is supposed to return more than one. But I want to filter the results trough another field, which would be type id (from the second Model) Here it is: class Category_info(models.Model): objtree_label_id = models.AutoField(primary_key = True) node_id = models.IntegerField(unique = True) language_id = models.IntegerField() label = models.CharField(max_length = 255) type_id = models.IntegerField() The type_id can be any number from 1 - 5. I am desparately trying to get only one result where the type_id would be number 1. Here is what I want in sql: SELECT n.*, l.* FROM objtree_nodes n JOIN objtree_labels l ON (n.node_id = l.node_id) WHERE n.type_id = 15 AND n.parent_id = 50 AND l.type_id = 1 Any help is GREATLY appreciated. Regards

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• Web Hosting: Any web host that supports files more than 50,000 in number?

  - by Devner

  Hi all, For my PHP & mySQL based application, I am trying to buy website hosting from a host who does not have a limit on the number of files I carry in my hosting account. Almost all the websites have a common limit of 50,000 files (some websites call it 50,000 nodes). The rest(to the extent of my search) are not even close. I have gone through the various websites, Googled lot of information, have spoken with the customer service of the hosting companies and they said that they have a limit of 50,000 files and that's why they call it the LIMIT. Now I have my application, which is a kind of social networking website, where people can upload various files of varying file size. So say if 50,000 users were to join the website and upload 1 file each, the limit of 50,000 will be reached very easily and my 50,001 customer will start facing file upload problems (& so will my account). So I would like to know if there's any website hosting services that do NOT levy such restrictions. In summary, I need the following options: No maximum file limit (more than 50,000 files in account). No maximum file upload limit in server setting (10MB, 12MB, 15MB, 20MB, etc.). Ability to upload files of various types (zip, flv, jg, png, etc.). Ability to stream Audio and Video (live audio & video not necessary). Access to .htaccess Access to php.ini, my.cnf or my.ini (this would be a plus) Supports SSL. Provides dedicated hosting(& IP) as well. Monthly payments without contracts are a plus. If you know of any such website hosting services, please post a reply ( a link to the same will be appreciated ). Thank you.

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• How can I improve the performance of LinqToSql queries that use EntitySet properties?

  - by DanM

  I'm using LinqToSql to query a small, simple SQL Server CE database. I've noticed that any operations involving sub-properties are disappointingly slow. For example, if I have a Customer table that is referenced by an Order table, LinqToSql will automatically create an EntitySet<Order> property. This is a nice convenience, allowing me to do things like Customer.Order.Where(o => o.ProductName = "Stopwatch"), but for some reason, SQL Server CE hangs up pretty bad when I try to do stuff like this. One of my queries, which isn't really that complicated takes 3-4 seconds to complete. I can get the speed up to acceptable, even fast, if I just grab the two tables individually and convert them to List<Customer> and List<Order>, then join then manually with my own query, but this is throwing out a lot of what makes LinqToSql so appealing. So, I'm wondering if I can somehow get the whole database into RAM and just query that way, then occasionally save it. Is this possible? How? If not, is there anything else I can do to boost the performance besides resorting to doing all the joins manually? Note: My database in its initial state is about 250K and I don't expect it to grow to more than 1-2Mb. So, loading the data into RAM certainly wouldn't be a problem from a memory point of view. Update Here are the table definitions for the example I used in my question: create table Order ( Id int identity(1, 1) primary key, ProductName ntext null ) create table Customer ( Id int identity(1, 1) primary key, OrderId int null references Order (Id) )

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• How important is the programming language when you choose a new job?

  - by Luhmann

  We are currently hiring at the company where I work, and here the codebase is in VB.Net. We are worried that we miss out on a lot of brilliant programmers, who would never ever consider working with VB.Net. My own background is Java and C#, and I was somewhat sceptical as to whether it would work out with VB, as - to be honest - i didn't care much for VB. After a month or so, I was completely fluent in VB, and a few months later i discovered to my surprise, that I actually like VB. I still code my free time projects in C# and Boo though. So my question is firstly, how important is language for you, when you choose a new programming job? Lets say if its a great company, salary is good, and generally an attractive work-place. Would you say no to the perfect job, if the language wasn't your preferred dialect? VB or C# is one thing, but how about Java or C# etc. Secondly if the best developers won't join your company because of your language or platform, would you consider changing, to get the right people? (This is not a language bashing thread, so please no religious language wars) NB: This is Community Wiki

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• VB dataset issue

  - by Gabriel

  Hi. The idea was to create a message box that stores my user name, message, and post datetime into the database as messages are sent. Soon came to realise, what if the user changed his name? So I decided to use the user id (icn) to identify the message poster instead. However, my chunk of codes keep giving me the same error. Says that there are no rows in the dataset ds2. I've tried my Query on my SQL and it works perfectly so I really really need help to spot the error in my chunk of codes here. Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim name As String Dim icn As String Dim message As String Dim time As String Dim tags As String = "" Dim strConn As System.Configuration.ConnectionStringSettings strConn = ConfigurationManager.ConnectionStrings("ufadb") Dim conn As SqlConnection = New SqlConnection(strConn.ToString()) Dim cmd As New SqlCommand("Select * From Message", conn) Dim daMessages As SqlDataAdapter = New SqlDataAdapter(cmd) Dim ds As New DataSet cmd.Connection.Open() daMessages.Fill(ds, "Messages") cmd.Connection.Close() If ds.Tables("Messages").Rows.Count > 0 Then Dim n As Integer = ds.Tables("Messages").Rows.Count Dim i As Integer For i = 0 To n - 1 icn = ds.Tables("Messages").Rows(i).Item("icn") Dim cmd2 As New SqlCommand("SELECT name FROM Member inner join Message ON Member.icn = Message.icn WHERE message.icn = @icn", conn) cmd2.Parameters.AddWithValue("@icn", icn) Dim daName As SqlDataAdapter = New SqlDataAdapter(cmd2) Dim ds2 As New DataSet cmd2.Connection.Open() daName.Fill(ds2, "PosterName") cmd2.Connection.Close() name = ds2.Tables("PosterName").Rows(0).Item("name") message = ds.Tables("Messages").Rows(i).Item("message") time = ds.Tables("Messages").Rows(i).Item("timePosted") tags = time + vbCrLf + name + ": " + vbCrLf + message + vbCrLf + tags Next txtBoard.Text = tags Else txtBoard.Text = "nothing to display" End If End Sub Help will be very much appreciated as I have been on this simple problem for 2 days.

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• Using HABTM relationships in cakephp plugins with unique set to false

  - by Dean

  I am working on a plugin for our CakePHP CMS that will handle blogs. When getting to the tags I needed to set the HABTM relationship to unique = false to be able add tags to a post without having to reset them all. The BlogPost model looks like this class BlogPost extends AppModel { var $name = 'BlogPost'; var $actsAs = array('Core.WhoDidIt', 'Containable'); var $hasMany = array('Blog.BlogPostComment'); var $hasAndBelongsToMany = array('Blog.BlogTag' => array('unique' => false), 'Blog.BlogCategory'); } The BlogTag model looks like this class BlogTag extends AppModel { var $name = 'BlogTag'; var $actsAs = array('Containable'); var $hasAndBelongsToMany = array('Blog.BlogPost'); } The SQL error I am getting when I have the unique = true setting in the HABTM relationship between the BlogPost and BlogTag is Query: SELECT `Blog`.`BlogTag`.`id`, `Blog`.`BlogTag`.`name`, `Blog`.`BlogTag`.`slug`, `Blog`.`BlogTag`.`created_by`, `Blog`.`BlogTag`.`modified_by`, `Blog`.`BlogTag`.`created`, `Blog`.`BlogTag`.`modified`, `BlogPostsBlogTag`.`blog_post_id`, `BlogPostsBlogTag`.`blog_tag_id` FROM `blog_tags` AS `Blog`.`BlogTag` JOIN `blog_posts_blog_tags` AS `BlogPostsBlogTag` ON (`BlogPostsBlogTag`.`blog_post_id` = 4 AND `BlogPostsBlogTag`.`blog_tag_id` = `Blog`.`BlogTag`.`id`) As you can see it is trying to set the blog_tags table to 'Blog'.'BlogTag. which isn't a valid MySQL name. When I remove the unique = true from the relationship it all works find and I can save one tag but when adding another it just erases the first one and puts the new one in its place. Does anyone have any ideas? is it a bug or am I just missing something? Cheers, Dean

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• How to print contents from a session variable by looping in a foreach statement

  - by itsover9000

  im trying to write a code where can print and loop through the contents of my session variable by using a foreach statement here is my code <form class="form form-inline" method = "post" action="reportmaker.php"> <select name="rfield"> <option value="">--Select Field--</option> <?php $sc2=mysql_query("SELECT * from searchcolumn s left join report_fields r on s.scol_id=r.field_id where s.category != 'wh'"); foreach($sc2 as $sc){ ?> <option value="<?php echo $sc[advsearch_col]; ?>"><?php echo $sc[advsearch_name]; ?></option> <?php } ?> </select> <button type="submit" value = "submit" id="add" name="add" class="btn pull-right">Add More</button> </form> <?php if(isset($_POST['add'])) { $_SESSION['temp'][]=$_POST['rfield']; } if($_SESSION[temp][]!=""){ foreach($_SESSION[temp][] as $temp) { echo $temp; } } ?> the error that appears with this code is Fatal error: Cannot use [] for reading the line where the error is is this if($_SESSION[temp][]!=""){ i need to print the contents of the session array and this is the only way i know how is there a way to fix this? thanks =========EDIT thanks for the answers guys i finally got it

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• Why does Hibernate 2nd level cache only cache queries within a session?

  - by Synesso

  Using a named query in our application and with ehcache as the provider, it seems that the query results are tied to the session within the cache. Any attempt to access the value from the cache for a second time results in a LazyInitializationException We have set lazy = true for the following mapping because this object is also used by another part of the system which does not require the reference... and we want to keep it lean. <class name="domain.ReferenceAdPoint" table="ad_point" mutable="false" lazy="false"> <cache usage="read-only"/> <id name="code" type="long" column="ad_point_id"> <generator class="assigned" /> </id> <property name="name" column="ad_point_description" type="string"/> <set name="synonyms" table="ad_point_synonym" cascade="all-delete-orphan" lazy="true"> <cache usage="read-only"/> <key column="ad_point_id" /> <element type="string" column="synonym_description" /> </set> </class> <query name="find.adpoints.by.heading">from ReferenceAdPoint adpoint left outer join fetch adpoint.synonyms where adpoint.adPointField.headingCode = ?</query> Here's a snippet from our hibernate.cfg.xml <property name="hibernate.cache.provider_class">net.sf.ehcache.hibernate.SingletonEhCacheProvider</property> <property name="hibernate.cache.use_query_cache">true</property> It doesn't seem to make sense that the cache would be constrained to the session. Why are the cached queries not usable outside of the (relatively short-lived) sessions?

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