RE: Suggestion/Idea for iterate tag: Iterate ResultSets
Well, I guess a way to work around that problem would be to create a data structure to represent the entire resultset. This could be a LinkedList of hashtables, with each key being the column name, and the value being the result. The disadvantage of this approach is that is requires the entire resultset to be loaded into memory, which may have some performance problems, right? --min -Original Message- From: Jonathan Asbell [mailto:[EMAIL PROTECTED]] Sent: Sunday, May 06, 2001 11:47 PM To: [EMAIL PROTECTED] Subject: Re: Suggestion/Idea for iterate tag: Iterate ResultSets Result sets ARE tied to the connection in a way. Some DB drivers throw exceptions when you try to manipulate data while you still have a pointer to rows. At work we were trying to manipulate a stream which was pointing to an output parameter in a stored proc while the connection was open. The result was that we had to convert the stream into another object (String in our case) and close the connection just to manipulate the data. - Original Message - From: Mindaugas Idzelis [EMAIL PROTECTED] To: struts [EMAIL PROTECTED] Sent: Sunday, May 06, 2001 9:33 PM Subject: Suggestion/Idea for iterate tag: Iterate ResultSets I just thought up of an excellent idea (although, I wasn't the only one). Use the iterate tag to iterate over the rows of a resultset. The column meta data could be exposed as beans named as the column name. A bean:write operation would display the data in the column. I did a search about this topic in the mailing list archive, and I found this message: http://marc.theaimsgroup.com/?l=struts-userm=98269295229785w=2 It talk about ResultSets being tied to connections. This is not the case. ResultSets are tied to the statements that produced them, and as far as I can tell, statements are not closed when the connection is closed. Other than that, It should be easy to change the iterate tag to support resultsets. If anyone is interested in helping me extend or develop a tag for this purpose, please message me. --min
RE: Suggestion/Idea for iterate tag: Iterate ResultSets
I just thought of another option: If resultsets are tied to a connection and a statement, then specify the sql query within the iterator: Hypothetical taglibs: sql:query id=myQuery SELECT col1, col2 FROM table WHERE id 1 !-- even use bean:write in here to dynamically make queries -- /sql:query logic:iterate id=row query=myQuery bean:write name=row property=col1/ bean:write name=row property=col2/ br /logic:iterate Where sql:query would only be evauluated once per iteration. Would this be possible to create? I have never authored a taglib, so any feedback from taglib veterans is greatly appreciated. I think this would be a great addition to the taglibs framework. --min -Original Message- From: Jonathan Asbell [mailto:[EMAIL PROTECTED]] Sent: Sunday, May 06, 2001 11:47 PM To: [EMAIL PROTECTED] Subject: Re: Suggestion/Idea for iterate tag: Iterate ResultSets Result sets ARE tied to the connection in a way. Some DB drivers throw exceptions when you try to manipulate data while you still have a pointer to rows. At work we were trying to manipulate a stream which was pointing to an output parameter in a stored proc while the connection was open. The result was that we had to convert the stream into another object (String in our case) and close the connection just to manipulate the data. - Original Message - From: Mindaugas Idzelis [EMAIL PROTECTED] To: struts [EMAIL PROTECTED] Sent: Sunday, May 06, 2001 9:33 PM Subject: Suggestion/Idea for iterate tag: Iterate ResultSets I just thought up of an excellent idea (although, I wasn't the only one). Use the iterate tag to iterate over the rows of a resultset. The column meta data could be exposed as beans named as the column name. A bean:write operation would display the data in the column. I did a search about this topic in the mailing list archive, and I found this message: http://marc.theaimsgroup.com/?l=struts-userm=98269295229785w=2 It talk about ResultSets being tied to connections. This is not the case. ResultSets are tied to the statements that produced them, and as far as I can tell, statements are not closed when the connection is closed. Other than that, It should be easy to change the iterate tag to support resultsets. If anyone is interested in helping me extend or develop a tag for this purpose, please message me. --min
RE: Suggestion/Idea for iterate tag: Iterate ResultSets
If you are interested in executing SQL from your JSPs, the taglibs project might save you some time. Check into: http://jakarta.apache.org/taglibs/doc/dbtags-doc/intro.html For what its worth, this approach breaks the model-view separation struts may have provided for your project. If that's ok for your project, then the afore-mentioned taglibs should save you time. On the other hand, if your not sure what model-view separation is, I would recommend reviewing the Struts User's Guide - Introduction at: http://jakarta.apache.org/struts/userGuide/introduction.html Regards, Levi Cook -Original Message- From: Mindaugas Idzelis [mailto:[EMAIL PROTECTED]] Sent: Monday, May 07, 2001 9:06 AM To: [EMAIL PROTECTED]; Jonathan Asbell Subject: RE: Suggestion/Idea for iterate tag: Iterate ResultSets I just thought of another option: If resultsets are tied to a connection and a statement, then specify the sql query within the iterator: Hypothetical taglibs: sql:query id=myQuery SELECT col1, col2 FROM table WHERE id 1 !-- even use bean:write in here to dynamically make queries -- /sql:query logic:iterate id=row query=myQuery bean:write name=row property=col1/ bean:write name=row property=col2/ br /logic:iterate Where sql:query would only be evauluated once per iteration. Would this be possible to create? I have never authored a taglib, so any feedback from taglib veterans is greatly appreciated. I think this would be a great addition to the taglibs framework. --min -Original Message- From: Jonathan Asbell [mailto:[EMAIL PROTECTED]] Sent: Sunday, May 06, 2001 11:47 PM To: [EMAIL PROTECTED] Subject: Re: Suggestion/Idea for iterate tag: Iterate ResultSets Result sets ARE tied to the connection in a way. Some DB drivers throw exceptions when you try to manipulate data while you still have a pointer to rows. At work we were trying to manipulate a stream which was pointing to an output parameter in a stored proc while the connection was open. The result was that we had to convert the stream into another object (String in our case) and close the connection just to manipulate the data. - Original Message - From: Mindaugas Idzelis [EMAIL PROTECTED] To: struts [EMAIL PROTECTED] Sent: Sunday, May 06, 2001 9:33 PM Subject: Suggestion/Idea for iterate tag: Iterate ResultSets I just thought up of an excellent idea (although, I wasn't the only one). Use the iterate tag to iterate over the rows of a resultset. The column meta data could be exposed as beans named as the column name. A bean:write operation would display the data in the column. I did a search about this topic in the mailing list archive, and I found this message: http://marc.theaimsgroup.com/?l=struts-userm=98269295229785w=2 It talk about ResultSets being tied to connections. This is not the case. ResultSets are tied to the statements that produced them, and as far as I can tell, statements are not closed when the connection is closed. Other than that, It should be easy to change the iterate tag to support resultsets. If anyone is interested in helping me extend or develop a tag for this purpose, please message me. --min
RE: Suggestion/Idea for iterate tag: Iterate ResultSets
I think Struts does a good job dealing with the whole MVC separation issues... Embedding SQL into yet-another-custom tag seems to (IMHO) violate a number of the principles Struts is trying to uphold. Truth-be-told, I haven't been a real JSP/custom tag fan from the start (aren't there enough languages to learn alrady? *:^) after spending countless hours sifting through bugs in other folkk's ASP pages and ColdFusion pages, but the whole Struts framework feels right and does a great job letting you have a *manageable*, *flexible* and *structured* view while doing most of the controller work for you, leaving only the icky model details to really work out. The fact that it works with Java is icing on the cake *:^) Tossing SQL directly into the view re-introduces the potential for unmanageabe web code (again, IMHO). It would be great to hear from those who have dealt with this more in the Java world, tho, on their feelings of SQL-JSP-MVC. As an aside, there is a good start on SQL taglibs - the DBTags tag library - in the jakarta-taglibs project - http://jakarta.apache.org/taglibs/doc/dbtags-doc/intro.html in case an individual wanted to see how to integrate this into Struts w/o re-inventing the wheel. An excerpt from their example page yields the following (which looks similar to what you were trying to do): %-- print the rows in an HTML table --% table sql:statement id=stmt1 conn=conn1 sql:query select id, name, description from test_books order by 1 /sql:query %-- loop through the rows of your query --% sql:resultSet id=rset2 tr tdsql:getColumn position=1//td tdsql:getColumn position=2//td tdsql:getColumn position=3/ %-- print out a comment if the book has no description --% sql:wasNull[no description]/sql:wasNull/td /tr /sql:resultSet /sql:statement /table boB Rudis [EMAIL PROTECTED] http://www.rudis.net/ ++ | Mind the gap | ++ On Mon, 7 May 2001, Mindaugas Idzelis wrote: I just thought of another option: If resultsets are tied to a connection and a statement, then specify the sql query within the iterator: Hypothetical taglibs: sql:query id=myQuery SELECT col1, col2 FROM table WHERE id 1 !-- even use bean:write in here to dynamically make queries -- /sql:query logic:iterate id=row query=myQuery bean:write name=row property=col1/ bean:write name=row property=col2/ br /logic:iterate Where sql:query would only be evauluated once per iteration. Would this be possible to create? I have never authored a taglib, so any feedback from taglib veterans is greatly appreciated. I think this would be a great addition to the taglibs framework. --min -Original Message- From: Jonathan Asbell [mailto:[EMAIL PROTECTED]] Sent: Sunday, May 06, 2001 11:47 PM To: [EMAIL PROTECTED] Subject: Re: Suggestion/Idea for iterate tag: Iterate ResultSets Result sets ARE tied to the connection in a way. Some DB drivers throw exceptions when you try to manipulate data while you still have a pointer to rows. At work we were trying to manipulate a stream which was pointing to an output parameter in a stored proc while the connection was open. The result was that we had to convert the stream into another object (String in our case) and close the connection just to manipulate the data. - Original Message - From: Mindaugas Idzelis [EMAIL PROTECTED] To: struts [EMAIL PROTECTED] Sent: Sunday, May 06, 2001 9:33 PM Subject: Suggestion/Idea for iterate tag: Iterate ResultSets I just thought up of an excellent idea (although, I wasn't the only one). Use the iterate tag to iterate over the rows of a resultset. The column meta data could be exposed as beans named as the column name. A bean:write operation would display the data in the column. I did a search about this topic in the mailing list archive, and I found this message: http://marc.theaimsgroup.com/?l=struts-userm=98269295229785w=2 It talk about ResultSets being tied to connections. This is not the case. ResultSets are tied to the statements that produced them, and as far as I can tell, statements are not closed when the connection is closed. Other than that, It should be easy to change the iterate tag to support resultsets. If anyone is interested in helping me extend or develop a tag for this purpose, please message me. --min
RE: Suggestion/Idea for iterate tag: Iterate ResultSets
I haven't used it, but this looks similar to whats been developed in the jakarta taglibs project - see JDBC taglib. http://jakarta.apache.org/taglibs/doc/jdbc-doc/intro.html Niall -Original Message- From: Mindaugas Idzelis [mailto:[EMAIL PROTECTED]] Sent: 07 May 2001 15:06 To: [EMAIL PROTECTED]; Jonathan Asbell Subject: RE: Suggestion/Idea for iterate tag: Iterate ResultSets I just thought of another option: If resultsets are tied to a connection and a statement, then specify the sql query within the iterator: Hypothetical taglibs: sql:query id=myQuery SELECT col1, col2 FROM table WHERE id 1 !-- even use bean:write in here to dynamically make queries -- /sql:query logic:iterate id=row query=myQuery bean:write name=row property=col1/ bean:write name=row property=col2/ br /logic:iterate Where sql:query would only be evauluated once per iteration. Would this be possible to create? I have never authored a taglib, so any feedback from taglib veterans is greatly appreciated. I think this would be a great addition to the taglibs framework. --min -Original Message- From: Jonathan Asbell [mailto:[EMAIL PROTECTED]] Sent: Sunday, May 06, 2001 11:47 PM To: [EMAIL PROTECTED] Subject: Re: Suggestion/Idea for iterate tag: Iterate ResultSets Result sets ARE tied to the connection in a way. Some DB drivers throw exceptions when you try to manipulate data while you still have a pointer to rows. At work we were trying to manipulate a stream which was pointing to an output parameter in a stored proc while the connection was open. The result was that we had to convert the stream into another object (String in our case) and close the connection just to manipulate the data. - Original Message - From: Mindaugas Idzelis [EMAIL PROTECTED] To: struts [EMAIL PROTECTED] Sent: Sunday, May 06, 2001 9:33 PM Subject: Suggestion/Idea for iterate tag: Iterate ResultSets I just thought up of an excellent idea (although, I wasn't the only one). Use the iterate tag to iterate over the rows of a resultset. The column meta data could be exposed as beans named as the column name. A bean:write operation would display the data in the column. I did a search about this topic in the mailing list archive, and I found this message: http://marc.theaimsgroup.com/?l=struts-userm=98269295229785w=2 It talk about ResultSets being tied to connections. This is not the case. ResultSets are tied to the statements that produced them, and as far as I can tell, statements are not closed when the connection is closed. Other than that, It should be easy to change the iterate tag to support resultsets. If anyone is interested in helping me extend or develop a tag for this purpose, please message me. --min
RE: Suggestion/Idea for iterate tag: Iterate ResultSets
See this for remote resultsets... http://developer.java.sun.com/developer/earlyAccess/crs/ also there is a good section in Professional Java Server Programming J2EE Edition (Wrox press) Page 587 on a TableModel tag library... Lewis -Original Message- From: Mindaugas Idzelis [mailto:[EMAIL PROTECTED]] Sent: 07 May 2001 02:33 To: struts Subject: Suggestion/Idea for iterate tag: Iterate ResultSets I just thought up of an excellent idea (although, I wasn't the only one). Use the iterate tag to iterate over the rows of a resultset. The column meta data could be exposed as beans named as the column name. A bean:write operation would display the data in the column. I did a search about this topic in the mailing list archive, and I found this message: http://marc.theaimsgroup.com/?l=struts-userm=98269295229785w=2 It talk about ResultSets being tied to connections. This is not the case. ResultSets are tied to the statements that produced them, and as far as I can tell, statements are not closed when the connection is closed. Other than that, It should be easy to change the iterate tag to support resultsets. If anyone is interested in helping me extend or develop a tag for this purpose, please message me. --min
Re: Suggestion/Idea for iterate tag: Iterate ResultSets
Result sets ARE tied to the connection in a way. Some DB drivers throw exceptions when you try to manipulate data while you still have a pointer to rows. At work we were trying to manipulate a stream which was pointing to an output parameter in a stored proc while the connection was open. The result was that we had to convert the stream into another object (String in our case) and close the connection just to manipulate the data. - Original Message - From: Mindaugas Idzelis [EMAIL PROTECTED] To: struts [EMAIL PROTECTED] Sent: Sunday, May 06, 2001 9:33 PM Subject: Suggestion/Idea for iterate tag: Iterate ResultSets I just thought up of an excellent idea (although, I wasn't the only one). Use the iterate tag to iterate over the rows of a resultset. The column meta data could be exposed as beans named as the column name. A bean:write operation would display the data in the column. I did a search about this topic in the mailing list archive, and I found this message: http://marc.theaimsgroup.com/?l=struts-userm=98269295229785w=2 It talk about ResultSets being tied to connections. This is not the case. ResultSets are tied to the statements that produced them, and as far as I can tell, statements are not closed when the connection is closed. Other than that, It should be easy to change the iterate tag to support resultsets. If anyone is interested in helping me extend or develop a tag for this purpose, please message me. --min
