Re: Modeler Exception for using dots on attributes

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Tue Jan 13 2009 - 11:44:37 EST

  • Next message: Javi Peter: "RE: Modeler Exception for using dots on attributes"

    Hi Javier,

    This is definitely a limitation, and as you've discovered, there are 2
    issues here.

    1. Dot is a standard path separator in Cayenne (you are the first one
    in so many years of Cayenne who has dots in column names; I am not
    saying this is illegal, rather that nobody in the community has done
    it before). So looks like we'll need to have some internal escaping of
    dots invisible to the user. May not be too hard to implement (?)

    2. Quoting identifiers. This is something that we were going to do for
    some time, but never got around to actually doing it (we have a few
    Jiras on it).

    There is a workaround for #2 - use quotes in the modeler for the
    attribute names. There's no workaround for #1, and this is a bug IMO
    (and as I said, hopefully not a hard one to fix). If you can open a
    Jira on that, I'd appreciate it. If not, I can do it myself.

    Thanks,
    Andrus

    On Jan 13, 2009, at 6:21 PM, Javi Peter wrote:
    >
    > Hi again,
    >
    > I´ve been doing some debugging and I think I have found the root of
    > the problem. In order to do the following debugs I had to edit the
    > mapping file manually (because the modeler hangs).
    >
    > We have to take into account that a query statement for a column
    > "mail.host" of the table "account" like "SELECT t0.mail.host,
    > t0.others FROM account t0" will fail, and it must be queried like
    > "SELECT t0.`mail.host`, t0.others FROM account t0".
    >
    > I launched a simple test and it failed with this exception:
    >
    > INFO QueryLogger: *** error.
    > org.apache.cayenne.exp.ExpressionException: [v.2.0.4 October 8 2007]
    > Can't resolve path component: [account.mail].
    > at org.apache.cayenne.map.Entity$PathIterator.next(Entity.java:363)
    > at
    > org
    > .apache
    > .cayenne
    > .access
    > .trans.SelectTranslator.appendQueryColumns(SelectTranslator.java:377)
    > at
    > org
    > .apache
    > .cayenne
    > .access
    > .trans.SelectTranslator.buildResultColumns(SelectTranslator.java:338)
    > at
    > org
    > .apache
    > .cayenne
    > .access.trans.SelectTranslator.createSqlString(SelectTranslator.java:
    > 113)
    > at
    > org
    > .apache
    > .cayenne
    > .dba
    > .mysql
    > .MySQLSelectTranslator.createSqlString(MySQLSelectTranslator.java:31)
    > at
    > org
    > .apache
    > .cayenne
    > .access.trans.QueryAssembler.createStatement(QueryAssembler.java:95)
    > [...]
    >
    > The problem there was a StringTokenizer in
    > org.apache.cayenne.map.Entity (line 331) which in method next()
    > thinks that the dot of "mail.host" is another token so it treats it
    > like two attributes instead of one. Changing manually the variable
    > on debug mode and changing back again after the tokenizer, it
    > finally forms the SQL statement, but the bad one, so again we get an
    > exception:
    >
    > com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: Unknown column
    > 't0.mail.host' in 'field list'
    > at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1026)
    > at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
    > at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3515)
    > at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3447)
    > at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1951)
    > at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2101)
    > at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2554)
    > at
    > com
    > .mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:
    > 1761)
    > [..]
    >
    > A search for the root of this exception lead me to
    > org.apache.cayenne.access.trans.SelectTranslator, where the
    > ArrayList "colums" gets filled and there it is the ColumnDescriptor
    > for our column, and the qualifiedColumnName is "t0.mail.host", which
    > of course won´t work. Changing it to "t0.`mail.host`" builds the
    > correct SELECT statement and finally works.
    >
    > Is this a bug or am I missing something?
    > Javier Rubio
    >
    >
    >> From: javipete..otmail.com
    >> To: use..ayenne.apache.org
    >> Subject: RE: Modeler Exception for using dots on attributes
    >> Date: Tue, 13 Jan 2009 09:07:09 +0100
    >>
    >>
    >> Sure: "account" is the table, "mail.imap.minidletime" is the column
    >> name.
    >>
    >> Thanks in advance
    >> Javier
    >>
    >>> From: andru..bjectstyle.org
    >>> To: use..ayenne.apache.org
    >>> Subject: Re: Modeler Exception for using dots on attributes
    >>> Date: Mon, 12 Jan 2009 19:32:08 +0200
    >>>
    >>> So "account.mail" is a COLUMN name? Not a table + column name?
    >>>
    >>> Could you clarify please.
    >>>
    >>> Thanks,
    >>> Andrus
    >>>
    >>>
    >>> On Jan 12, 2009, at 7:10 PM, Javi Peter wrote:
    >>>
    >>>>
    >>>> Hi,
    >>>>
    >>>> each time I reverse engineer a database schema with dots (e.g.
    >>>> "mail.account"), the modeler hangs. If I hit Validate Project, it
    >>>> shows the exception shown at the end of the email.
    >>>> It also happens if I create manually the ObjAttribute.
    >>>>
    >>>> Any ideas of why this happens and how to workaround this (I MUST
    >>>> use
    >>>> dots).
    >>>>
    >>>> Thanks,
    >>>> Javier Rubio
    >>>>
    >>>>
    >>>> CayenneModeler Info
    >>>> Version: 2.0.4
    >>>> Build Date: October 8 2007
    >>>> Exception:
    >>>> =================================
    >>>> org.apache.cayenne.exp.ExpressionException: [v.2.0.4 October 8
    >>>> 2007]
    >>>> Can't resolve path component: [account.mail].
    >>>> at org.apache.cayenne.map.Entity$PathIterator.next(Entity.java:
    >>>> 363)
    >>>> at
    >>>> org
    >>>> .apache.cayenne.map.ObjAttribute.getDbAttribute(ObjAttribute.java:
    >>>> 147)
    >>>> at
    >>>> org
    >>>> .apache
    >>>> .cayenne
    >>>> .util.EntityMergeSupport.getMeaningfulFKs(EntityMergeSupport.java:
    >>>> 173)
    >>>> at
    >>>> org
    >>>> .apache
    >>>> .cayenne
    >>>> .modeler
    >>>> .dialog
    >>>> .objentity
    >>>> .EntitySyncController.createMerger(EntitySyncController.java:69)
    >>>> at
    >>>> org
    >>>> .apache
    >>>> .cayenne
    >>>> .modeler
    >>>> .action.DbEntitySyncAction.synchDbEntity(DbEntitySyncAction.java:
    >>>> 75)
    >>>> at
    >>>> org
    >>>> .apache
    >>>> .cayenne
    >>>> .modeler
    >>>> .action.DbEntitySyncAction.performAction(DbEntitySyncAction.java:
    >>>> 60)
    >>>> at
    >>>> org
    >>>> .apache
    >>>> .cayenne
    >>>> .modeler.util.CayenneAction.actionPerformed(CayenneAction.java:163)
    >>>> at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
    >>>> at javax.swing.AbstractButton$Handler.actionPerformed(Unknown
    >>>> Source)
    >>>> at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown
    >>>> Source)
    >>>> at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
    >>>> at
    >>>> javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown
    >>>> Source)
    >>>> at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
    >>>> at java.awt.Component.processMouseEvent(Unknown Source)
    >>>> at javax.swing.JComponent.processMouseEvent(Unknown Source)
    >>>> at java.awt.Component.processEvent(Unknown Source)
    >>>> at java.awt.Container.processEvent(Unknown Source)
    >>>> at java.awt.Component.dispatchEventImpl(Unknown Source)
    >>>> at java.awt.Container.dispatchEventImpl(Unknown Source)
    >>>> at java.awt.Component.dispatchEvent(Unknown Source)
    >>>> at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown
    >>>> Source)
    >>>> at java.awt.LightweightDispatcher.processMouseEvent(Unknown
    >>>> Source)
    >>>> at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
    >>>> at java.awt.Container.dispatchEventImpl(Unknown Source)
    >>>> at java.awt.Window.dispatchEventImpl(Unknown Source)
    >>>> at java.awt.Component.dispatchEvent(Unknown Source)
    >>>> at java.awt.EventQueue.dispatchEvent(Unknown Source)
    >>>> at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown
    >>>> Source)
    >>>> at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown
    >>>> Source)
    >>>> at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    >>>> at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    >>>> at java.awt.EventDispatchThread.run(Unknown Source)
    >>>>
    >>>>
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    >>>
    >>
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