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  • HQL Query Not Running

    - by Sarang
    select new UpdateCountDataBean(count(elements(am.actionId)) as noOfUpdates, am.pname as name) from ActivityMaster am group by am.pname The UpdateCountDataBean is created by me while the second class i.e. ActivityMaster is POJO class. java.lang.NullPointerException at org.hibernate.hql.ast.tree.MethodNode.handleElements(MethodNode.java:158) at org.hibernate.hql.ast.tree.MethodNode.resolveCollectionProperty(MethodNode.java:109) at org.hibernate.hql.ast.tree.CollectionFunction.resolve(CollectionFunction.java:22) at org.hibernate.hql.ast.HqlSqlWalker.processFunction(HqlSqlWalker.java:835) at org.hibernate.hql.antlr.HqlSqlBaseWalker.collectionFunction(HqlSqlBaseWalker.java:2558) at org.hibernate.hql.antlr.HqlSqlBaseWalker.aggregateExpr(HqlSqlBaseWalker.java:2907) at org.hibernate.hql.antlr.HqlSqlBaseWalker.count(HqlSqlBaseWalker.java:2483) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExpr(HqlSqlBaseWalker.java:1971) at org.hibernate.hql.antlr.HqlSqlBaseWalker.aliasedSelectExpr(HqlSqlBaseWalker.java:2057) at org.hibernate.hql.antlr.HqlSqlBaseWalker.constructor(HqlSqlBaseWalker.java:2226) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExpr(HqlSqlBaseWalker.java:1952) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExprList(HqlSqlBaseWalker.java:1825) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectClause(HqlSqlBaseWalker.java:1394) at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:553) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:281) at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:229) at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:228) at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:160) at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:111) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:77) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:56) at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:72) at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:133) at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:112) at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1623)

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  • Custom HTTPHandler causing caching or session issues?

    - by Jan de Jager
    So i have a custom CMS running under .Net 3.5 written entirely in c#. The engine is optimized to render for mobile devices, but also server to normal web browsers. It also supports cookieless sessions. Great... I've chosen not to cache anything (including browser data) in order to control the rendering completely from data. This has been all good until lately. The engine implements a basic login function that simply logs the user state within a session object. The behavior is rather strange. User will click through the site no problem. Then login. The login will either go through successfully or just redisplay the login screen, suggesting a cached page being returned or redisplayed... If the login is successful the concurrent page hits will switch arbitrarily between logged in and logged out state... Also suggesting either the session state is not accessible or a cached page being returned. I have debugged the hell out of the thing.... including using fiddler and the like. When debugging the behavior disappears. Huh? One of the sites running on the engine is http://www.wiseguy.mobi (sorry customized for South Africa, so you'll probably not be able to get the password Text Message)!

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  • pyscripter Rpyc error

    - by jf328
    pyscripter 2.5.3.0 x64, python 2.7.7 anaconda 2.0.1, windows 7 I was using pyscripter and EPD python happily in 32 bit, no problem. Just changed to 64 bit anaconda version and re-installed everything but now pyscripter cannot import rpyc -- it runs with internal engine (no anaconda), but no such error in pure python. Thanks very much! btw, there is a similar SO post few years ago, but the answer there does not work. *** Python 2.7.3 (default, Apr 10 2012, 23:24:47) [MSC v.1500 64 bit (AMD64)] on win32. *** Internal Python engine is active *** *** Internal Python engine is active *** >>> import rpyc Traceback (most recent call last): File "<interactive input>", line 1, in <module> File "C:\Anaconda\lib\site-packages\rpyc\__init__.py", line 44, in <module> from rpyc.core import (SocketStream, TunneledSocketStream, PipeStream, Channel, File "C:\Anaconda\lib\site-packages\rpyc\core\__init__.py", line 1, in <module> from rpyc.core.stream import SocketStream, TunneledSocketStream, PipeStream File "C:\Anaconda\lib\site-packages\rpyc\core\stream.py", line 7, in <module> import socket File "C:\Anaconda\Lib\socket.py", line 47, in <module> import _socket ImportError: DLL load failed: The specified procedure could not be found. >>> C:\research>python Python 2.7.7 |Anaconda 2.0.1 (64-bit)| (default, Jun 11 2014, 10:40:02) [MSC v.1500 64bit (AMD64)] on win32 Type "help", "copyright", "credits" or "license" for more information. Anaconda is brought to you by Continuum Analytics. Please check out: http://continuum.io/thanks and https://binstar.org >>> import rpyc >>>

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  • Whats wrong with this HQL query?

    - by ManBugra
    did i encounter a hibernate bug or do i have an error i dont see: select enty.number from EntityAliasName enty where enty.myId in ( select cons.myId from Consens cons where cons.number in ( select ord.number from Orders ord where ord.customer = :customer and ord.creationDate < ( select max(ord.creationDate) from Orders ord where ord.customer = :customer ) ) ) what i do get is the following: org.hibernate.util.StringHelper.root(StringHelper.java:257) Caused by: java.lang.NullPointerException at org.hibernate.util.StringHelper.root(StringHelper.java:257) at org.hibernate.persister.entity.AbstractEntityPersister.getSubclassPropertyTableNumber(AbstractEntityPersister.java:1391) at org.hibernate.persister.entity.BasicEntityPropertyMapping.toColumns(BasicEntityPropertyMapping.java:54) at org.hibernate.persister.entity.AbstractEntityPersister.toColumns(AbstractEntityPersister.java:1367) at org.hibernate.hql.ast.tree.FromElement.getIdentityColumn(FromElement.java:320) at org.hibernate.hql.ast.tree.IdentNode.resolveAsAlias(IdentNode.java:154) at org.hibernate.hql.ast.tree.IdentNode.resolve(IdentNode.java:100) at org.hibernate.hql.ast.tree.FromReferenceNode.resolve(FromReferenceNode.java:117) at org.hibernate.hql.ast.tree.FromReferenceNode.resolve(FromReferenceNode.java:113) at org.hibernate.hql.ast.HqlSqlWalker.resolve(HqlSqlWalker.java:854) at org.hibernate.hql.antlr.HqlSqlBaseWalker.propertyRef(HqlSqlBaseWalker.java:1172) at org.hibernate.hql.antlr.HqlSqlBaseWalker.propertyRefLhs(HqlSqlBaseWalker.java:5167) at org.hibernate.hql.antlr.HqlSqlBaseWalker.propertyRef(HqlSqlBaseWalker.java:1133) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExpr(HqlSqlBaseWalker.java:1993) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExprList(HqlSqlBaseWalker.java:1932) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectClause(HqlSqlBaseWalker.java:1476) at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:580) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:288) at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:231) at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:254) at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:185) at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:136) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:101) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:80) at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:94) at org.hibernate.impl.SessionFactoryImpl.checkNamedQueries(SessionFactoryImpl.java:484) at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:394) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1341) using: Hibernate 3.3.2.GA / postgresql

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  • Default class for SQLAlchemy single table inheritance

    - by eclaird
    I've set up a single table inheritance, but I need a "default" class to use when an unknown polymorphic identity is encountered. The database is not in my control and so the data can be pretty much anything. A working example setup: import sqlalchemy as sa from sqlalchemy import orm engine = sa.create_engine('sqlite://') metadata = sa.MetaData(bind=engine) table = sa.Table('example_types', metadata, sa.Column('id', sa.Integer, primary_key=True), sa.Column('type', sa.Integer), ) metadata.create_all() class BaseType(object): pass class TypeA(BaseType): pass class TypeB(BaseType): pass base_mapper = orm.mapper(BaseType, table, polymorphic_on=table.c.type, polymorphic_identity=None, ) orm.mapper(TypeA, inherits=base_mapper, polymorphic_identity='A', ) orm.mapper(TypeB, inherits=base_mapper, polymorphic_identity='B', ) Session = orm.sessionmaker(autocommit=False, autoflush=False) session = Session() Now, if I insert a new unmapped identity... engine.execute('INSERT INTO EXAMPLE_TYPES (TYPE) VALUES (\'C\')') session.query(BaseType).first() ...things break. Traceback (most recent call last): File "<stdin>", line 1, in <module> File ".../SQLAlchemy-0.6.5-py2.6.egg/sqlalchemy/orm/query.py", line 1619, in first ret = list(self[0:1]) File ".../SQLAlchemy-0.6.5-py2.6.egg/sqlalchemy/orm/query.py", line 1528, in __getitem__ return list(res) File ".../SQLAlchemy-0.6.5-py2.6.egg/sqlalchemy/orm/query.py", line 1797, in instances rows = [process[0](row, None) for row in fetch] File ".../SQLAlchemy-0.6.5-py2.6.egg/sqlalchemy/orm/mapper.py", line 2179, in _instance _instance = polymorphic_instances[discriminator] File ".../SQLAlchemy-0.6.5-py2.6.egg/sqlalchemy/util.py", line 83, in __missing__ self[key] = val = self.creator(key) File ".../SQLAlchemy-0.6.5-py2.6.egg/sqlalchemy/orm/mapper.py", line 2341, in configure_subclass_mapper discriminator) AssertionError: No such polymorphic_identity u'C' is defined What I expected: >>> result = session.query(BaseType).first() >>> result <BaseType object at 0x1c8db70> >>> result.type u'C' I think this used to work with some older version of SQLAlchemy, but I haven't been keeping up with the development lately. Any pointers on how to accomplish this?

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  • question about InnoDB deadlock in MySQL?

    - by WilliamLou
    I found this kind of interesting problem in MySQL InnoDB engine, could anyone explain why the engine always claim it's a deadlock. First, I created a table with a single row, single column: CREATE TABLE `SeqNum` (`current_seq_num` bigint(30) NOT NULL default '0', PRIMARY KEY (`current_seq_num`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 | Now, I have two MySQL connector threads, In thread1: mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select `current_seq_num` into @curr_seq FROM SeqNum FOR UPDATE; Query OK, 1 row affected (0.00 sec) Now, in thread2, I did the exactly same: mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select `current_seq_num` into @curr_seq FROM SeqNum FOR UPDATE; before the default innodb_lock_wait_timeout, the thread2 just wait for thread1 to release its exclusive lock on the table, and it's normal. However, in thread1, if I input the following update query: mysql> update SeqNum set `current_seq_num` = 8; ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction Now, thread2 get the select query finished because thread1 quits. In addition, in thread1, if I input the update query with a where clause, it can be executed very well: mysql> update SeqNum set `current_seq_num` = 8 where `current_seq_num` =5 Query OK, 1 row affected (0.00 sec) Could anyone explain this?

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  • Twitter Typeahead only shows only 5 results

    - by user3685388
    I'm using the Twitter Typeahead version 0.10.2 autocomplete but I'm only receiving 5 results from my JSON result set. I can have 20 or more results but only 5 are shown. What am I doing wrong? var engine = new Bloodhound({ name: "blackboard-names", prefetch: { url: "../CFC/Login.cfc?method=Search&returnformat=json&term=%QUERY", ajax: { contentType: "json", cache: false } }, remote: { url: "../CFC/Login.cfc?method=Search&returnformat=json&term=%QUERY", ajax: { contentType: "json", cache: false }, }, datumTokenizer: Bloodhound.tokenizers.obj.whitespace('value'), queryTokenizer: Bloodhound.tokenizers.whitespace }); var promise = engine.initialize(); promise .done(function() { console.log("done"); }) .fail(function() { console.log("fail"); }); $("#Impersonate").typeahead({ minLength: 2, highlight: true}, { name: "blackboard-names", displayKey: 'value', source: engine.ttAdapter() }).bind("typeahead:selected", function(obj, datum, name) { console.log(obj, datum, name); alert(datum.id); }); Data: [ { "id": "1", "value": "Adams, Abigail", "tokens": [ "Adams", "A", "Ad", "Ada", "Abigail", "A", "Ab", "Abi" ] }, { "id": "2", "value": "Adams, Alan", "tokens": [ "Adams", "A", "Ad", "Ada", "Alan", "A", "Al", "Ala" ] }, { "id": "3", "value": "Adams, Alison", "tokens": [ "Adams", "A", "Ad", "Ada", "Alison", "A", "Al", "Ali" ] }, { "id": "4", "value": "Adams, Amber", "tokens": [ "Adams", "A", "Ad", "Ada", "Amber", "A", "Am", "Amb" ] }, { "id": "5", "value": "Adams, Amelia", "tokens": [ "Adams", "A", "Ad", "Ada", "Amelia", "A", "Am", "Ame" ] }, { "id": "6", "value": "Adams, Arik", "tokens": [ "Adams", "A", "Ad", "Ada", "Arik", "A", "Ar", "Ari" ] }, { "id": "7", "value": "Adams, Ashele", "tokens": [ "Adams", "A", "Ad", "Ada", "Ashele", "A", "As", "Ash" ] }, { "id": "8", "value": "Adams, Brady", "tokens": [ "Adams", "A", "Ad", "Ada", "Brady", "B", "Br", "Bra" ] }, { "id": "9", "value": "Adams, Brandon", "tokens": [ "Adams", "A", "Ad", "Ada", "Brandon", "B", "Br", "Bra" ] } ]

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  • org.hibernate.hql.ast.QuerySyntaxException: TABLE NAME is not mapped

    - by Coronatus
    I have two models, Item and ShopSection. They have a many-to-many relationship. @Entity(name = "item") public class Item extends Model { @ManyToMany(cascade = CascadeType.PERSIST) public Set<ShopSection> sections; } @Entity(name = "shop_section") public class ShopSection extends Model { public List<Item> findActiveItems(int page, int length) { return Item.find("select distinct i from Item i join i.sections as s where s.id = ?", id).fetch(page, length); } } findActiveItems is meant to find items in a section, but I get this error: org.hibernate.hql.ast.QuerySyntaxException: Item is not mapped [select distinct i from Item i join i.sections as s where s.id = ?] at org.hibernate.hql.ast.util.SessionFactoryHelper.requireClassPersister(SessionFactoryHelper.java:180) at org.hibernate.hql.ast.tree.FromElementFactory.addFromElement(FromElementFactory.java:111) at org.hibernate.hql.ast.tree.FromClause.addFromElement(FromClause.java:93) at org.hibernate.hql.ast.HqlSqlWalker.createFromElement(HqlSqlWalker.java:322) at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElement(HqlSqlBaseWalker.java:3441) at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElementList(HqlSqlBaseWalker.java:3325) at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromClause(HqlSqlBaseWalker.java:733) at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:584) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:301) at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:244) at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:254) at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:185) at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:136) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:101) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:80) at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:124) at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:156) at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:135) at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1770) at org.hibernate.ejb.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:272) ... 8 more What am I doing wrong?

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  • Trying to use Rhino, getEngineByName("JavaScript") returns null in OpenJDK 7

    - by Yuval
    When I run the following piece of code, the engine variable is set to null when I'm using OepnJDK 7 (java-7-openjdk-i386). import javax.script.ScriptEngine; import javax.script.ScriptEngineManager; import javax.script.ScriptException; public class TestRhino { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub ScriptEngineManager factory = new ScriptEngineManager(); ScriptEngine engine = factory.getEngineByName("JavaScript"); try { System.out.println(engine.eval("1+1")); } catch (ScriptException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } It runs fine with java-6-openjdk and Oracle's jre1.7.0. Any idea why? I'm using Ubuntu 11.10. All JVMs are installed under /usr/lib/jvm. I noticed OpenJDK 7 has a different directory structure. Perhaps something is not installed right? $ locate rhino.jar /usr/lib/jvm/java-6-openjdk/jre/lib/rhino.jar /usr/lib/jvm/java-7-openjdk-common/jre/lib/rhino.jar /usr/lib/jvm/java-7-openjdk-i386/jre/lib/rhino.jar Edit Since ScriptEngineManager uses a ServiceProvider to find the available script engines, I snooped around resources.jar's META-INF/services. I noticed that in OpenJDK 6, resources.jar has a META-INF/services/javax.script.ScriptEngineFactory entry which is missing from OpenJDK 7. Any idea why? I suspect this is a bug? Here is the contents of that entry (from OpenJDK 6): #script engines supported com.sun.script.javascript.RhinoScriptEngineFactory #javascript Another edit Apparently, according to this thread, the code simply isn't there, perhaps because of merging issues between Sun and Mozilla code. I still don't understand why it was present in OpenJDK 6 and not 7. The class com.sun.script.javascript.RhinoScriptEngineFactory exists in 6's rt.jar but not in 7's. If it was not meant to be included, why is there a OpenJDK 7 rhino.jar then; and why is the source still in the OpenJDK source tree (here)?

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  • Hibernate Auto-Increment Setup

    - by dharga
    How do I define an entity for the following table. I've got something that isn't working and I just want to see what I'm supposed to do. USE [BAMPI_TP_dev] GO SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO SET ANSI_PADDING ON GO CREATE TABLE [dbo].[MemberSelectedOptions]( [OptionId] [int] NOT NULL, [SeqNo] [smallint] IDENTITY(1,1) NOT NULL, [OptionStatusCd] [char](1) NULL ) ON [PRIMARY] GO SET ANSI_PADDING OFF This is what I have already that isn't working. @Entity @Table(schema="dbo", name="MemberSelectedOptions") public class MemberSelectedOption extends BampiEntity implements Serializable { @Embeddable public static class MSOPK implements Serializable { private static final long serialVersionUID = 1L; @Column(name="OptionId") int optionId; @GeneratedValue(strategy=GenerationType.IDENTITY) @Column(name="SeqNo", unique=true, nullable=false) BigDecimal seqNo; //Getters and setters here... } private static final long serialVersionUID = 1L; @EmbeddedId MSOPK pk = new MSOPK(); @Column(name="OptionStatusCd") String optionStatusCd; //More Getters and setters here... } I get the following ST. [5/25/10 15:49:40:221 EDT] 0000003d JDBCException E org.slf4j.impl.JCLLoggerAdapter error Cannot insert explicit value for identity column in table 'MemberSelectedOptions' when IDENTITY_INSERT is set to OFF. [5/25/10 15:49:40:221 EDT] 0000003d AbstractFlush E org.slf4j.impl.JCLLoggerAdapter error Could not synchronize database state with session org.hibernate.exception.SQLGrammarException: could not insert: [com.bob.proj.ws.model.MemberSelectedOption] at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:90) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2285) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2678) at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:79) at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:167) at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1028) at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:366) at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:137) at com.bcbst.bamp.ws.dao.MemberSelectedOptionDAOImpl.saveMemberSelectedOption(MemberSelectedOptionDAOImpl.java:143) at com.bcbst.bamp.ws.common.AlertReminder.saveMemberSelectedOptions(AlertReminder.java:76) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

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  • sqlalchemy relation through another (declarative)

    - by clayg
    Is anyone familiar with ActiveRecord's "has_many :through" relations for models? I'm not really a Rails guy, but that's basically what I'm trying to do. As a contrived example consider Projects, Programmers, and Assignments: from sqlalchemy import create_engine from sqlalchemy.orm import sessionmaker from sqlalchemy import Column, ForeignKey from sqlalchemy.types import Integer, String, Text from sqlalchemy.orm import relation from sqlalchemy.ext.declarative import declarative_base Base = declarative_base() class Assignment(Base): __tablename__ = 'assignment' id = Column(Integer, primary_key=True) description = Column(Text) programmer_id = Column(Integer, ForeignKey('programmer.id')) project_id = Column(Integer, ForeignKey('project.id')) def __init__(self, description=description): self.description = description def __repr__(self): return '<Assignment("%s")>' % self.description class Programmer(Base): __tablename__ = 'programmer' id = Column(Integer, primary_key=True) name = Column(String(64)) assignments = relation("Assignment", backref='programmer') def __init__(self, name=name): self.name = name def __repr__(self): return '<Programmer("%s")>' % self.name class Project(Base): __tablename__ = 'project' id = Column(Integer, primary_key=True) name = Column(String(64)) description = Column(Text) assignments = relation("Assignment", backref='project') def __init__(self, name=name, description=description): self.name = name self.description = description def __repr__(self): return '<Project("%s", "%s...")>' % (self.name, self.description[:10]) engine = create_engine('sqlite://') Base.metadata.create_all(engine) Session = sessionmaker(bind=engine) session = Session() Projects have many Assignments. Programmers have many Assignments. (understatement?) But in my office at least, Programmers also have many Projects - I'd like this relationship to be inferred through the Assignments assigned to the Programmer. I'd like the Programmer model to have a attribute "projects" which will return a list of Projects associated to the Programmer through the Assignment model. me = session.query(Programmer).filter_by(name='clay').one() projects = session.query(Project).\ join(Project.assignments).\ join(Assignment.programmer).\ filter(Programmer.id==me.id).all() How can I describe this relationship clearly and simply using the sqlalchemy declarative syntax? Thanks!

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  • what libraries or platforms should I use to build web apps that provide real-time, asynchronous data

    - by Daniel Sterling
    This is a less a question with a simple, practical answer and more a question to foster discussion on the real-time data exchange topic. I'll begin with an example: Google Wave is, at its core, a real-time asynchronous data synchronization engine. Wave supports (or plans to support) concurrent (real-time) document collaboration, disconnected (offline) document editing, conflict resolution, document history and playback with attribution, and server federation. A core part of Wave is the Operational Transformation engine: http://www.waveprotocol.org/whitepapers/operational-transform The OT engine manages document state. Changes between clients are merged and each client has a sane and consistent view of the document at all times; the final document is eventually consistent between all connected clients. My question is: is this system abstract or general enough to be used as a library or generic framework upon which to build web apps that synchronize real-time, asynchronous state in each client? Is the Wave protocol directly used by any current web applications (besides Google's client)? Would it make sense to directly use it for generic state synchronization in a web app? What other existing libraries or frameworks would you consider using when building such a web app? How much code in such an app might be domain-specific logic vs generic state synchronization logic? Or, put another way, how leaky might the state synchronization abstractions be? Comments and discussion welcomed!

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  • SEO: Where do I start?

    - by James
    Hi, I am primarily a software developer however I tend to delve in some web development from time to time. I have recently been asked to have a look at a friends website as they are wanting to improve their position in search engine results i.e. google/yahoo etc. I am aware there is no guarentee that their position will change, however, I do know there are techniques/ways to make your website more visible to search engine spiders and to consequently improve your position in the rankings i.e. performing SEO. Before I started looking at the SEO of the site I did the following prerequsite checks: Ran the website through the W3C Markup Validator and the W3C CSS Validator services. Looked through the markup code manually (check for meta tags etc) Performed a thorough cross browser compatibility test. From those checks, the following was evident: No SEO has been performed on the site before. The website has been developed using a visual editing tool such as dreamweaver (as it failed the validation services miserably and tables where being used everywhere!) The site is fairly cross browser compatibile (only some slight issues with IE8 which are easily resolved). How the site navigation is, isn't very search engine friendly (e.g. index.php?page=home) I can see right away a major improvement for SEO (or I at least think) would be to change the way the website is structured i.e. change from using dynamic pages such as "index.php?page=home" and actually having pages called "home.html". Other area's would be to add meta tags to identify keywords, and then sprinkling these keywords over the pages. As I am a rookie in this department, could anyone give me some advice on how I could perform thorough SEO on this website? Thanks in advance.

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  • Creating self-referential tables with polymorphism in SQLALchemy

    - by Jace
    I'm trying to create a db structure in which I have many types of content entities, of which one, a Comment, can be attached to any other. Consider the following: from datetime import datetime from sqlalchemy import create_engine from sqlalchemy import Column, ForeignKey from sqlalchemy import Unicode, Integer, DateTime from sqlalchemy.orm import relation, backref from sqlalchemy.ext.declarative import declarative_base Base = declarative_base() class Entity(Base): __tablename__ = 'entities' id = Column(Integer, primary_key=True) created_at = Column(DateTime, default=datetime.utcnow, nullable=False) edited_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False) type = Column(Unicode(20), nullable=False) __mapper_args__ = {'polymorphic_on': type} # <...insert some models based on Entity...> class Comment(Entity): __tablename__ = 'comments' __mapper_args__ = {'polymorphic_identity': u'comment'} id = Column(None, ForeignKey('entities.id'), primary_key=True) _idref = relation(Entity, foreign_keys=id, primaryjoin=id == Entity.id) attached_to_id = Column(Integer, ForeignKey('entities.id'), nullable=False) #attached_to = relation(Entity, remote_side=[Entity.id]) attached_to = relation(Entity, foreign_keys=attached_to_id, primaryjoin=attached_to_id == Entity.id, backref=backref('comments', cascade="all, delete-orphan")) text = Column(Unicode(255), nullable=False) engine = create_engine('sqlite://', echo=True) Base.metadata.bind = engine Base.metadata.create_all(engine) This seems about right, except SQLAlchemy doesn't like having two foreign keys pointing to the same parent. It says ArgumentError: Can't determine join between 'entities' and 'comments'; tables have more than one foreign key constraint relationship between them. Please specify the 'onclause' of this join explicitly. How do I specify onclause?

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  • Modeling objects with multiple table relationships in Zend Framework

    - by andybaird
    I'm toying with Zend Framework and trying to use the "QuickStart" guide against a website I'm making just to see how the process would work. Forgive me if this answer is obvious, hopefully someone experienced can shed some light on this. I have three database tables: CREATE TABLE `users` ( `id` int(11) NOT NULL auto_increment, `email` varchar(255) NOT NULL, `username` varchar(255) NOT NULL default '', `first` varchar(128) NOT NULL default '', `last` varchar(128) NOT NULL default '', `gender` enum('M','F') default NULL, `birthyear` year(4) default NULL, `postal` varchar(16) default NULL, `auth_method` enum('Default','OpenID','Facebook','Disabled') NOT NULL default 'Default', PRIMARY KEY (`id`), UNIQUE KEY `email` (`email`), UNIQUE KEY `username` (`username`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 CREATE TABLE `user_password` ( `user_id` int(11) NOT NULL, `password` varchar(16) NOT NULL default '', PRIMARY KEY (`user_id`), UNIQUE KEY `user_id` (`user_id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 CREATE TABLE `user_metadata` ( `user_id` int(11) NOT NULL default '0', `signup_date` datetime default NULL, `signup_ip` varchar(15) default NULL, `last_login_date` datetime default NULL, `last_login_ip` varchar(15) default NULL, PRIMARY KEY (`user_id`), UNIQUE KEY `user_id` (`user_id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 I want to create a User model that uses all three tables in certain situations. E.g., the metadata table is accessed if/when the meta data is needed. The user_password table is accessed only if the 'Default' auth_method is set. I'll likely be adding a profile table later on that I would like to be able to access from the user model. What is the best way to do this with ZF and why?

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  • How do I join three tables with SQLalchemy and keeping all of the columns in one of the tables?

    - by jimka
    So, I have three tables: The class defenitions: engine = create_engine('sqlite://test.db', echo=False) SQLSession = sessionmaker(bind=engine) Base = declarative_base() class Channel(Base): __tablename__ = 'channel' id = Column(Integer, primary_key = True) title = Column(String) description = Column(String) link = Column(String) pubDate = Column(DateTime) class User(Base): __tablename__ = 'user' id = Column(Integer, primary_key = True) username = Column(String) password = Column(String) sessionId = Column(String) class Subscription(Base): __tablename__ = 'subscription' userId = Column(Integer, ForeignKey('user.id'), primary_key=True) channelId = Column(Integer, ForeignKey('channel.id'), primary_key=True) And the SQL commands that are executed to create them: CREATE TABLE subscription ( "userId" INTEGER NOT NULL, "channelId" INTEGER NOT NULL, PRIMARY KEY ("userId", "channelId"), FOREIGN KEY("userId") REFERENCES user (id), FOREIGN KEY("channelId") REFERENCES channel (id) ); CREATE TABLE user ( id INTEGER NOT NULL, username VARCHAR, password VARCHAR, "sessionId" VARCHAR, PRIMARY KEY (id) ); CREATE TABLE channel ( id INTEGER NOT NULL, title VARCHAR, description VARCHAR, link VARCHAR, "pubDate" TIMESTAMP, PRIMARY KEY (id) ); NOTE: I know user.username should be unique, need to fix that, and I'm not sure why SQLalchemy creates some row names with the double-quotes. And I'm trying to come up with a way to retrieve all of the channels, as well as an indication on what channels one particular user (identified by user.sessionId together with user.id) has a subscription on. For example, say we have four channels: channel1, channel2, channel3, channel4; a user: user1; who has a subscription on channel1 and channel4. The query for user1 would return something like: channel.id | channel.title | subscribed --------------------------------------- 1 channel1 True 2 channel2 False 3 channel3 False 4 channel4 True This is a best-case result, but since I have absolutely no clue as how to accomplish the subscribed column, I've been instead trying to get the particular users id in the rows where the user has a subscription and where a subscription is missing, just leave it blank. The database engine that I'm using together with SQLalchemy atm. is sqlite3 I've been scratching my head over this for two days now, I've no problem joining together all three by way of the subscription table but then all of the channels where the user does not have a subscription gets omitted. I hope I've managed to describe my problem sufficiently, thanks in advance.

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  • atk4 advanced crud?

    - by thindery
    I have the following tables: -- ----------------------------------------------------- -- Table `product` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `product` ( `id` INT NOT NULL AUTO_INCREMENT , `productName` VARCHAR(255) NULL , `s7location` VARCHAR(255) NULL , PRIMARY KEY (`id`) ) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `pages` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `pages` ( `id` INT NOT NULL AUTO_INCREMENT , `productID` INT NULL , `pageName` VARCHAR(255) NOT NULL , `isBlank` TINYINT(1) NULL , `pageOrder` INT(11) NULL , `s7page` INT(11) NULL , PRIMARY KEY (`id`) , INDEX `productID` (`productID` ASC) , CONSTRAINT `productID` FOREIGN KEY (`productID` ) REFERENCES `product` (`id` ) ON DELETE NO ACTION ON UPDATE NO ACTION) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `field` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `field` ( `id` INT NOT NULL AUTO_INCREMENT , `pagesID` INT NULL , `fieldName` VARCHAR(255) NOT NULL , `fieldType` VARCHAR(255) NOT NULL , `fieldDefaultValue` VARCHAR(255) NULL , PRIMARY KEY (`id`) , INDEX `id` (`pagesID` ASC) , CONSTRAINT `pagesID` FOREIGN KEY (`pagesID` ) REFERENCES `pages` (`id` ) ON DELETE NO ACTION ON UPDATE NO ACTION) ENGINE = InnoDB; I have gotten CRUD to work on the 'product' table. //addproduct.php class page_addproduct extends Page { function init(){ parent::init(); $crud=$this->add('CRUD')->setModel('Product'); } } This works. but I need to get it so that when a new product is created it basically allows me to add new rows into the pages and field tables. For example, the products in the tables are a print product(like a greeting card) that has multiple pages to render. Page 1 may have 2 text fields that can be customized, page 2 may have 3 text fields, a slider to define text size, and a drop down list to pick a color, and page 3 may have five text fields that can all be customized. All three pages (and all form elements, 12 in this example) are associated with 1 product. So when I create the product, could i add a button to create a page for that product, then within the page i can add a button to add a new form element field? I'm still somewhat new to this, so my db structure may not be ideal. i'd appreciate any suggestions and feedback! Could someone point me toward some information, tutorials, documentation, ideas, suggestions, on how I can implement this?

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  • mysql whats wrong with this query?

    - by Hailwood
    I'm trying to write a query that selects from four tables campaignSentParent csp campaignSentEmail cse campaignSentFax csf campaignSentSms css Each of the cse, csf, and css tables are linked to the csp table by csp.id = (cse/csf/css).parentId The csp table has a column called campaignId, What I want to do is end up with rows that look like: | id | dateSent | emailsSent | faxsSent | smssSent | | 1 | 2011-02-04 | 139 | 129 | 140 | But instead I end up with a row that looks like: | 1 | 2011-02-03 | 2510340 | 2510340 | 2510340 | Here is the query I am trying SELECT csp.id id, csp.dateSent dateSent, COUNT(cse.parentId) emailsSent, COUNT(csf.parentId) faxsSent, COUNT(css.parentId) smsSent FROM campaignSentParent csp, campaignSentEmail cse, campaignSentFax csf, campaignSentSms css WHERE csp.campaignId = 1 AND csf.parentId = csp.id AND cse.parentId = csp.id AND css.parentId = csp.id; Adding GROUP BY did not help, so I am posting the create statements. csp CREATE TABLE `campaignsentparent` ( `id` int(11) NOT NULL AUTO_INCREMENT, `campaignId` int(11) NOT NULL, `dateSent` datetime NOT NULL, `account` int(11) NOT NULL, `status` varchar(15) NOT NULL DEFAULT 'Creating', PRIMARY KEY (`id`) ) ENGINE=MyISAM AUTO_INCREMENT=2 DEFAULT CHARSET=latin1 cse/csf (same structure, different names) CREATE TABLE `campaignsentemail` ( `id` int(11) NOT NULL AUTO_INCREMENT, `parentId` int(11) NOT NULL, `contactId` int(11) NOT NULL, `content` text, `subject` text, `status` varchar(15) DEFAULT 'Pending', PRIMARY KEY (`id`) ) ENGINE=MyISAM AUTO_INCREMENT=140 DEFAULT CHARSET=latin1 css CREATE TABLE `campaignsentsms` ( `id` int(11) NOT NULL AUTO_INCREMENT, `parentId` int(11) NOT NULL, `contactId` int(11) NOT NULL, `content` text, `status` varchar(15) DEFAULT 'Pending', PRIMARY KEY (`id`) ) ENGINE=MyISAM AUTO_INCREMENT=141 DEFAULT CHARSET=latin1

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  • How Can i Create This Complicated Query ?

    - by mTuran
    Hi, I have 3 tables: projects, skills and project_skills. In projects table i hold project's general data. Second table skills i hold skill id and skill name also i have projects_skills table which is hold project's skill relationships. Here is scheme of tables: CREATE TABLE IF NOT EXISTS `project_skills` ( `project_id` int(11) NOT NULL, `skill_id` int(11) NOT NULL, KEY `project_id` (`project_id`), KEY `skill_id` (`skill_id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_turkish_ci; CREATE TABLE IF NOT EXISTS `projects` ( `id` int(11) NOT NULL AUTO_INCREMENT, `employer_id` int(11) NOT NULL, `project_title` varchar(100) COLLATE utf8_turkish_ci NOT NULL, `project_description` text COLLATE utf8_turkish_ci NOT NULL, `project_budget` int(11) NOT NULL, `project_allowedtime` int(11) NOT NULL, `project_deadline` datetime NOT NULL, `total_bids` int(11) NOT NULL, `average_bid` int(11) NOT NULL, `created` datetime NOT NULL, `active` tinyint(1) NOT NULL, PRIMARY KEY (`id`), KEY `created` (`created`), KEY `employer_id` (`employer_id`), KEY `active` (`active`), FULLTEXT KEY `project_title` (`project_title`,`project_description`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_turkish_ci AUTO_INCREMENT=3 ; CREATE TABLE IF NOT EXISTS `skills` ( `id` int(11) NOT NULL AUTO_INCREMENT, `category` int(11) NOT NULL, `name` varchar(100) COLLATE utf8_turkish_ci NOT NULL, `seo_name` varchar(100) COLLATE utf8_turkish_ci NOT NULL, `total_projects` int(11) NOT NULL, PRIMARY KEY (`id`), KEY `seo_name` (`seo_name`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_turkish_ci AUTO_INCREMENT=224 ; I want to select projects with related skill names. I think i have to use JOIN but i don't know how can i do. Thanks

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  • Setting up relations/mappings for a SQLAlchemy many-to-many database

    - by Brent Ramerth
    I'm new to SQLAlchemy and relational databases, and I'm trying to set up a model for an annotated lexicon. I want to support an arbitrary number of key-value annotations for the words which can be added or removed at runtime. Since there will be a lot of repetition in the names of the keys, I don't want to use this solution directly, although the code is similar. My design has word objects and property objects. The words and properties are stored in separate tables with a property_values table that links the two. Here's the code: from sqlalchemy import Column, Integer, String, Table, create_engine from sqlalchemy import MetaData, ForeignKey from sqlalchemy.orm import relation, mapper, sessionmaker from sqlalchemy.ext.declarative import declarative_base engine = create_engine('sqlite:///test.db', echo=True) meta = MetaData(bind=engine) property_values = Table('property_values', meta, Column('word_id', Integer, ForeignKey('words.id')), Column('property_id', Integer, ForeignKey('properties.id')), Column('value', String(20)) ) words = Table('words', meta, Column('id', Integer, primary_key=True), Column('name', String(20)), Column('freq', Integer) ) properties = Table('properties', meta, Column('id', Integer, primary_key=True), Column('name', String(20), nullable=False, unique=True) ) meta.create_all() class Word(object): def __init__(self, name, freq=1): self.name = name self.freq = freq class Property(object): def __init__(self, name): self.name = name mapper(Property, properties) Now I'd like to be able to do the following: Session = sessionmaker(bind=engine) s = Session() word = Word('foo', 42) word['bar'] = 'yes' # or word.bar = 'yes' ? s.add(word) s.commit() Ideally this should add 1|foo|42 to the words table, add 1|bar to the properties table, and add 1|1|yes to the property_values table. However, I don't have the right mappings and relations in place to make this happen. I get the sense from reading the documentation at http://www.sqlalchemy.org/docs/05/mappers.html#association-pattern that I want to use an association proxy or something of that sort here, but the syntax is unclear to me. I experimented with this: mapper(Word, words, properties={ 'properties': relation(Property, secondary=property_values) }) but this mapper only fills in the foreign key values, and I need to fill in the other value as well. Any assistance would be greatly appreciated.

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  • mysql query help, take total sum from a table, and based on discount value on another table calcula

    - by vegatron
    hi I have a table called invoices: CREATE TABLE IF NOT EXISTS `si_invoices` ( `id` int(10) NOT NULL AUTO_INCREMENT, `biller_id` int(10) NOT NULL DEFAULT '0', `customer_id` int(10) NOT NULL DEFAULT '0', `type_id` int(10) NOT NULL DEFAULT '0', `inv_tax_id` int(10) NOT NULL, `date` date NOT NULL DEFAULT '0000-00-00', `unreg_customer` tinyint(1) NOT NULL DEFAULT '0', `discount` decimal(10,2) NOT NULL DEFAULT '0.00', `discount_type` tinyint(1) NOT NULL DEFAULT '0', PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=20 ; each invoice has items that are stored in invoice_items table : CREATE TABLE IF NOT EXISTS `si_invoice_items` ( `id` int(10) NOT NULL AUTO_INCREMENT, `invoice_id` int(10) NOT NULL DEFAULT '0', `quantity` int(10) unsigned NOT NULL DEFAULT '0', `product_id` int(10) DEFAULT '0', `warehouse_id` int(10) NOT NULL, `unit_price` decimal(25,2) DEFAULT '0.00', `total` decimal(25,2) DEFAULT '0.00', `description` text, PRIMARY KEY (`id`), KEY `invoice_id` (`invoice_id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=56 ; and tax table CREATE TABLE IF NOT EXISTS `si_tax` ( `tax_id` int(11) NOT NULL AUTO_INCREMENT, `tax_description` varchar(50) COLLATE utf8_unicode_ci DEFAULT NULL, `tax_percentage` decimal(25,6) DEFAULT '0.000000', `type` varchar(1) COLLATE utf8_unicode_ci DEFAULT NULL, `tax_enabled` varchar(1) COLLATE utf8_unicode_ci NOT NULL DEFAULT '1', PRIMARY KEY (`tax_id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=5 ; here is what I want to do step 1: get the sum_total of the invoice Items for a speciefic invoice step 2: calculate the discount, in the invoice table I have a discount_type field : if its equal to 0 , then there will be no discount if its equal to 1 , the discount value will be stored in the discount field if its equal to 2 , the discount is a percentage of sum_total step 3: calculate the taxes based on inv_tax_id based on the tax id , I will look in the tax table , get the tax_percentage and multiply it by the (sum_total - discount) in short here is the equation $gross_total = $sum_total - $disount + taxes

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  • C# / IronPython Interop with shared C# Class Library

    - by Adam Haile
    I'm trying to use IronPython as an intermediary between a C# GUI and some C# libraries, so that it can be scripted post compile time. I have a Class library DLL that is used by both the GUI and the python and is something along the lines of this: namespace MyLib { public class MyClass { public string Name { get; set; } public MyClass(string name) { this.Name = name; } } } The IronPython code is as follows: import clr clr.AddReferenceToFile(r"MyLib.dll") from MyLib import MyClass ReturnObject = MyClass("Test") Then, in C# I would call it as follows: ScriptEngine engine = Python.CreateEngine(); ScriptScope scope = null; scope = engine.CreateScope(); ScriptSource source = engine.CreateScriptSourceFromFile("Script.py"); source.Execute(scope); MyClass mc = scope.GetVariable<MyClass>("ReturnObject ") When I call this last bit of code, source.Execute(scope) runs returns successfully, but when I try the GetVariable call, it throw the following exception Microsoft.Scripting.ArgumentTypeException: expected MyClass , got MyClass So, you can see that the class names are exactly the same, but for some reason it thinks they are different. The DLL is in a different directory than the .py file (I just didn't bother to write out all the path setup stuff), could it be that there is an issue with the interpreter for IronPython seeing these objects as difference because it's somehow seeing them as being in a different context or scope?

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  • Java RMI Proxy issue

    - by Antony Lewis
    i am getting this error : java.lang.ClassCastException: $Proxy0 cannot be cast to rmi.engine.Call at Main.main(Main.java:39) my abstract and call class both extend remote. call: public class Call extends UnicastRemoteObject implements rmi.engine.Abstract { public Call() throws Exception { super(Store.PORT, new RClient(), new RServer()); } public String getHello() { System.out.println("CONN"); return "HEY"; } } abstract: public interface Abstract extends Remote { String getHello() throws RemoteException; } this is my main: public static void main(String[] args) { if (args.length == 0) { try { System.out.println("We are slave "); InetAddress ip = InetAddress.getLocalHost(); Registry rr = LocateRegistry.getRegistry(ip.getHostAddress(), Store.PORT, new RClient()); Object ss = rr.lookup("FILLER"); System.out.println(ss.getClass().getCanonicalName()); System.out.println(((Call)ss).getHello()); } catch (Exception e) { e.printStackTrace(); } } else { if (args[0].equals("master")) { // Start Master try { RMIServer.start(); } catch (Exception e) { e.printStackTrace(); } } Netbeans says the problem is on line 39 which is System.out.println(((Call)ss).getHello()); the output looks like this: run: We are slave Connecting 10.0.0.212:5225 $Proxy0 java.lang.ClassCastException: $Proxy0 cannot be cast to rmi.engine.Call at Main.main(Main.java:39) BUILD SUCCESSFUL (total time: 1 second) i am running a master in cmd listening on port 5225.

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  • What is the difference between Inversion of Control and Dependency injection in C++?

    - by rlbond
    I've been reading recently about DI and IoC in C++. I am a little confused (even after reading related questions here on SO) and was hoping for some clarification. It seems to me that being familiar with the STL and Boost leads to use of dependency injection quite a bit. For example, let's say I made a function that found the mean of a range of numbers: template <typename Iter> double mean(Iter first, Iter last) { double sum = 0; size_t number = 0; while (first != last) { sum += *(first++); ++number; } return sum/number; }; Is this dependency injection? Inversion of control? Neither? Let's look at another example. We have a class: class Dice { public: typedef boost::mt19937 Engine; Dice(int num_dice, Engine& rng) : n_(num_dice), eng_(rng) {} int roll() { int sum = 0; for (int i = 0; i < num_dice; ++i) sum += boost::uniform_int<>(1,6)(eng_); return sum; } private: Engine& eng_; int n_; }; This seems like dependency injection. But is it inversion of control? Also, if I'm missing something, can someone help me out?

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  • JOIN (SELECT DISTINCT [..] substitute

    - by FRKT
    Hello, I'd like to find a substitute for using SELECT DISTINCT in a derived table. Let's say I have three tables: CREATE TABLE `trades` ( `tradeID` int(11) unsigned NOT NULL AUTO_INCREMENT, `employeeID` int(11) unsigned NOT NULL, `corporationID` int(11) unsigned NOT NULL, `profit` int(11) NOT NULL, KEY `tradeID` (`tradeID`), KEY `employeeID` (`employeeID`), KEY `corporationID` (`corporationID`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 CREATE TABLE `corporations` ( `corporationID` int(11) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, PRIMARY KEY (`corporationID`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 CREATE TABLE `employees` ( `employeeID` int(11) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, PRIMARY KEY (`employeeID`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 Let's say I'd like to find out how much profit a specific employee has generated. Simple: SELECT SUM(profit) FROM trades JOIN employees ON trades.employeeID = employees.employeeID AND employees.employeeID = 1; It gets trickier if I'd like to query how much revenue a specific corporation has, however. I cannot simply replicate the aforementioned query, because two or more employees from the same company might be involved in the same trade. This query should do the trick: SELECT SUM(profit) FROM trades JOIN (SELECT DISTINCT tradeID FROM trades WHERE trades.corporationID = 1) ... unfortunately, DISTINCT JOINs seem crazy ineffective. Is there any alternative I can use to determine how much revenue a corporation has, taking into account that a corporation might be listed several times with the same tradeID?

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