Re: [lazarus] FPC question
On Fri, 21 Apr 2006 23:50:08 +0200 Graeme Geldenhuys [EMAIL PROTECTED] wrote: Thanks for the help! Any idea how to rename the title of a page? See the newly added tiOPF page. Currently the title is TiOPF and it should read tiOPF. I think MediaWiki automatically uppercases the first letter, I have no clue why though. This will probably need some PHP hacking to get right :-/. Micha _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Micha Nelissen wrote: On Fri, 21 Apr 2006 23:50:08 +0200 Graeme Geldenhuys [EMAIL PROTECTED] wrote: Thanks for the help! Any idea how to rename the title of a page? See the newly added tiOPF page. Currently the title is TiOPF and it should read tiOPF. I think MediaWiki automatically uppercases the first letter, I have no clue why though. This will probably need some PHP hacking to get right :-/. It is possible, look for example here: http://forums.macrumors.com/showthread.php?t=167613 It also lists the drawbacks. I don't know in what version of mediawiki this was added and how to set this flag, so if anybody can dig up that information, please send it to me. Vincent _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On 4/21/06, Graeme Geldenhuys [EMAIL PROTECTED] wrote: Any idea how to rename the title of a page? See the newly added tiOPF page. Currently the title is TiOPF and it should read tiOPF. Wikimedia automatically makes the first letter capitalized. If you read wikipedia often you will see many articles have notices saying that the first letter should not be capitalized but is, due to technical restrictions. This leads to the conclusion that only throught a hack on the software you may be able to create a non-capitalized title. It is probably easier to just use the title as it is and put a notice if you want to make it clear of the correct name. -- Felipe Monteiro de Carvalho _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Vincent Snijders wrote: Micha Nelissen wrote: On Fri, 21 Apr 2006 23:50:08 +0200 Graeme Geldenhuys [EMAIL PROTECTED] wrote: Thanks for the help! Any idea how to rename the title of a page? See the newly added tiOPF page. Currently the title is TiOPF and it should read tiOPF. I think MediaWiki automatically uppercases the first letter, I have no clue why though. This will probably need some PHP hacking to get right :-/. It is possible, look for example here: http://forums.macrumors.com/showthread.php?t=167613 It also lists the drawbacks. I don't know in what version of mediawiki this was added and how to set this flag, so if anybody can dig up that information, please send it to me. Both Sven Heinig and Micha Nelissen told me that I need to set wgCapitalLinks to false. Thanks. I just made this change. Doing this means that some links will get broken, i.e. links that start with a lowercase character, for example if the History page is referenced like [[history]]. This will need to be replaced by [[History|history]]. If you find them, please fix them. Vincent. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: tiOPF wiki page (was Re: [lazarus] FPC question)
Graeme Geldenhuys schreef: I added a link here: http://wiki.lazarus.freepascal.org/index.php/Components_and_Code_examples#Databases Feel free the change the name of the link. Then click on it, the wiki sees the page does not exist and you can start edit the empty page. Vincent. Okay, I added the content to the page, but I have two problems. 1) The title of the page is TiOPF where it should be tiOPF. No idea how to change that. I don't know that either. Vincent. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Any idea how to rename the title of a page? See the newly added tiOPF page. Currently the title is TiOPF and it should read tiOPF. Probably have to cut and paste, not sure if there is a rename function in wikis.. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Hi John, Maybe you should look at using a OPF (Object Persistent Framework) to solve your transaction issues, as well as lookups etc... I have ported the TechInsite tiOPF version 2 to Free Pascal and have been using it with Lazarus in a commercial environment for the last 8 months with great success. Before that I have used tiOPF under Delphi for the last 3 years. I understand that moving over to a OPF for data and object handling is a huge learning curve, but soon you will start reaping the rewards. One of the great things about using a OPF (and there are many others) is that DB handling is all done for you as well as transactions. All you need to work with is you related objects and just go Object.Save or Object.Load. Switching database backend is also a no brainer, just change a Compiler Define (nothing else in code changes). To read more about the tiOPF and how it works go to the following link. http://www.techinsite.com.au/tiOPF The website is a bit out of date, so is the documentation, but the internals of the OPF still apply to Ver.2. Regards, - Graeme - On 19/04/06, johnf [EMAIL PROTECTED] wrote: Since I believe I'm the guy that started this thread I think I'll take the time to explain in more detail how and why I started the thread. -- There's no place like 127.0.0.1 _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On 4/20/06, Graeme Geldenhuys [EMAIL PROTECTED] wrote: I have ported the TechInsite tiOPF version 2 to Free Pascal and have been using it with Lazarus in a commercial environment for the last 8 months with great success. Is this one free / open source or you have a commercial license and ported it for your needs? If not commercial please provide link to download. It would be great to have it in Lazarus. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Thu, 20 Apr 2006, Alexander Todorov wrote: On 4/20/06, Graeme Geldenhuys [EMAIL PROTECTED] wrote: I have ported the TechInsite tiOPF version 2 to Free Pascal and have been using it with Lazarus in a commercial environment for the last 8 months with great success. Is this one free / open source or you have a commercial license and ported it for your needs? If not commercial please provide link to download. It would be great to have it in Lazarus. The general page is http://www.techinsite.com.au/default.htm But the version 2 of tiOPF is in Subversion, and I don't have the link for that at the moment. Michael. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
The tiOPF is a open-source project for a few years now. As Michael said, Version 2 is in SubVersion. The SubVersion address is: http://tiopf.techinsite.com.au/svn/tiOPF2/Trunk Daily builds can be downloaded from: http://tiopf.techinsite.com.au/DailyBuild/Index.html tiOPF Support by news groups News Server: news.techinsite.com.au News Server port: 119 Web Interface:http://news.techinsite.com.au/webnews/ User name:anything as long as it is a single alphanumeric name. Website: http://www.techinsite.com.au/tiOPF/ Regards, - Graeme - On 20/04/06, Alexander Todorov [EMAIL PROTECTED] wrote: On 4/20/06, Graeme Geldenhuys [EMAIL PROTECTED] wrote: I have ported the TechInsite tiOPF version 2 to Free Pascal and have been using it with Lazarus in a commercial environment for the last 8 months with great success. Is this one free / open source or you have a commercial license and ported it for your needs? If not commercial please provide link to download. It would be great to have it in Lazarus. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives -- There's no place like 127.0.0.1 _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Graeme Geldenhuys wrote: Hi John, Maybe you should look at using a OPF (Object Persistent Framework) to solve your transaction issues, as well as lookups etc... I have ported the TechInsite tiOPF version 2 to Free Pascal and have been using it with Lazarus in a commercial environment for the last 8 months with great success. Before that I have used tiOPF under Delphi for the last 3 years. I understand that moving over to a OPF for data and object handling is a huge learning curve, but soon you will start reaping the rewards. One of the great things about using a OPF (and there are many others) is that DB handling is all done for you as well as transactions. All you need to work with is you related objects and just go Object.Save or Object.Load. Switching database backend is also a no brainer, just change a Compiler Define (nothing else in code changes). To read more about the tiOPF and how it works go to the following link. http://www.techinsite.com.au/tiOPF The website is a bit out of date, so is the documentation, but the internals of the OPF still apply to Ver.2. Can you create a source zip for upload to lazarus-ccr? Then it can be mentioned on http://wiki.lazarus.freepascal.org/index.php/Components_and_Code_examples Vincent. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On 20/04/06, Vincent Snijders [EMAIL PROTECTED] wrote: Can you create a source zip for upload to lazarus-ccr? Then it can be mentioned on http://wiki.lazarus.freepascal.org/index.php/Components_and_Code_examples Vincent. No problem. An official v2 release is due any time now, but in the mean while, I will zip up the Source folder. Do I email it to you? Regards, - Graeme - -- There's no place like 127.0.0.1 _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Graeme Geldenhuys wrote: On 20/04/06, Vincent Snijders [EMAIL PROTECTED] wrote: Can you create a source zip for upload to lazarus-ccr? Then it can be mentioned on http://wiki.lazarus.freepascal.org/index.php/Components_and_Code_examples Vincent. No problem. An official v2 release is due any time now, but in the mean while, I will zip up the Source folder. Do I email it to you? Yes. Maybe we can work on wiki description page too, like http://wiki.lazarus.freepascal.org/index.php/TAChart Vincent _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
2006/4/20, Graeme Geldenhuys [EMAIL PROTECTED]: On 20/04/06, Vincent Snijders [EMAIL PROTECTED] wrote: Can you create a source zip for upload to lazarus-ccr? Then it can be mentioned on http://wiki.lazarus.freepascal.org/index.php/Components_and_Code_examples Vincent. No problem. An official v2 release is due any time now, but in the mean while, I will zip up the Source folder. Do I email it to you? Native PostgreSQL access in v2 (asside using proprietary drivers)? :) -- Alexandre Leclerc _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On 20/04/06, Vincent Snijders [EMAIL PROTECTED] wrote: Maybe we can work on wiki description page too, like http://wiki.lazarus.freepascal.org/index.php/TAChart Vincent I was just looking at those pages. I don't know how to create/start a new wiki page, only edit current ones. Do you need special permissions to create new pages, if so could you create a blank/template page, and I will fill in the rest. (or I'll start reading the wiki help) What category in Components and Code examples would fit the OPF? Databases? Packages for FPC/Lazarus? Regards, -- There's no place like 127.0.0.1 _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Graeme Geldenhuys wrote: I was just looking at those pages. I don't know how to create/start a new wiki page, only edit current ones. Do you need special permissions to create new pages, if so could you create a blank/template page, and I will fill in the rest. (or I'll start reading the wiki help) Log into the wiki, then directly change the URL to have the pagename you want to use. For instance, if your topic is Test Blank do: http://wiki.lazarus.freepascal.org/index.php/TestBlank You'll get a page saying there's no text yet, then you just edit it. -Tony _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
tiOPF wiki page (was Re: [lazarus] FPC question)
Graeme Geldenhuys wrote: On 20/04/06, Vincent Snijders [EMAIL PROTECTED] wrote: Maybe we can work on wiki description page too, like http://wiki.lazarus.freepascal.org/index.php/TAChart Vincent I was just looking at those pages. I don't know how to create/start a new wiki page, only edit current ones. Do you need special permissions to create new pages, if so could you create a blank/template page, and I will fill in the rest. (or I'll start reading the wiki help) What category in Components and Code examples would fit the OPF? Databases? Packages for FPC/Lazarus? I added a link here: http://wiki.lazarus.freepascal.org/index.php/Components_and_Code_examples#Databases Feel free the change the name of the link. Then click on it, the wiki sees the page does not exist and you can start edit the empty page. Vincent. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Joost van der Sluis wrote: Is this a problem with PostrgreSQL itself or the component in lazarus wrapping it? It's a problem of postgres. A transaction 'block' is started with the sql-command 'begin', from that comand on, all queries are executed But you can do multiple queries in a block I suppose ? Multiple update, and one select, or so ? Micha _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Wed, 19 Apr 2006, Adrian Maier wrote: On 4/19/06, Joost van der Sluis [EMAIL PROTECTED] wrote: Is this a problem with PostrgreSQL itself or the component in lazarus wrapping it? It's a problem of postgres. A transaction 'block' is started with the sql-command 'begin', from that comand on, all queries are executed within that transaction. Using another connection is not possible. Unless, offcourse, you start a new connection. Or closes the transaction (commit, rollback etc) Please pardon me for jumping in the middle of the thread, but your phrase made me really curious. The behaviour you described seems to be the normal one, once you execute begin (transaction) . What other behaviour would someone expect postgres to have ? To allow several concurrent transactions. Interbase/Firebird allows to start several concurrent transactions in 1 connection. AFAIK Oracle and MS-SQL too (named transactions). This is extremely handy. Michael. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Wed, 19 Apr 2006, Micha Nelissen wrote: Joost van der Sluis wrote: Is this a problem with PostrgreSQL itself or the component in lazarus wrapping it? It's a problem of postgres. A transaction 'block' is started with the sql-command 'begin', from that comand on, all queries are executed But you can do multiple queries in a block I suppose ? Multiple update, and one select, or so ? Obviously, this is the whole idea of transactions ? :) Michael. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Michael Van Canneyt wrote: But you can do multiple queries in a block I suppose ? Multiple update, and one select, or so ? Obviously, this is the whole idea of transactions ? :) Then I don't see why multiple concurrent transactions are useful ? The user can only do one thing at a time anyway, right? :-) Micha _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Wed, 19 Apr 2006, Micha Nelissen wrote: Michael Van Canneyt wrote: But you can do multiple queries in a block I suppose ? Multiple update, and one select, or so ? Obviously, this is the whole idea of transactions ? :) Then I don't see why multiple concurrent transactions are useful ? The user can only do one thing at a time anyway, right? :-) Didn't you implement threads ? ;-) Not if you make e.g. some reports in the background, using threads. For server apps, multiple transactions in a connection are a must. My apps at work depend on it: one connection to the database, and at least 1 transaction per user... Michael. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Michael Van Canneyt wrote: Then I don't see why multiple concurrent transactions are useful ? The user can only do one thing at a time anyway, right? :-) Didn't you implement threads ? ;-) Not if you make e.g. some reports in the background, using threads. Hmm I didn't expect multiple transactions on one connection to be thread safe. For server apps, multiple transactions in a connection are a must. My apps at work depend on it: one connection to the database, and at least 1 transaction per user... The 'middle' tier, you mean ? Why is the single connection a must ? Micha _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Tue, 2006-04-18 at 14:27 -0700, johnf wrote: On Tuesday 18 April 2006 13:42, Marc Santhoff wrote: Am Dienstag, den 18.04.2006, 21:29 +0200 schrieb Joost van der Sluis: On Tue, 2006-04-18 at 14:43 -0400, Alexandre Leclerc wrote: 2006/4/18, Joost van der Sluis [EMAIL PROTECTED]: But you can have one connection, whith several transactions bound to it. PostgreSQL doesn't support that, but SQLdb handles that for you, it creates new connection internally automatically. Do you mean TPQConnection does not support many TSQLTransaction? 'But you can have one connection, whith several transactions bound to it.' So you can. Only PostgreSQL can't, so SQLDdb handles it. May I ask: Is this a problem with PostrgreSQL itself or the component in lazarus wrapping it? I'm planning to use PG in the near future, but this may influence my decision ... TIA, Marc I can't answer your question directly. But I can provide a little information about what I have added to this discussion. First let me say that I have always used only one connection to a database engine and controlled all of my transactions in code in the past (just to let you know where I'm coming from). But with FPC I was not able to use just one connection to the database. There's a difference between 'FPC can't' and 'PostgreSQL can't' Since FPC can do this, but postgresql can't. So sqldb hides the creation of a second connection to the database. If that doesn't work, it's a bug. But in the case of postgres you should not think of connections. In reality, it has no connections, it only has transactions! You open a transaction to the database... -- Met vriendelijke groeten, Joost van der Sluis CNOC Informatiesystemen en Netwerken http://www.cnoc.nl _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Wed, 2006-04-19 at 09:22 +0200, Micha Nelissen wrote: But you can do multiple queries in a block I suppose ? Multiple update, and one select, or so ? Yes, you can even do multiple selects. But what you can't do is rollback only a part of the block. (well.. there are safepoints, but not important for this example) And you can't isolate the different select statements within one block. JoJo, Joost _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Wed, 2006-04-19 at 10:22 +0300, Adrian Maier wrote:
On 4/19/06, Joost van der Sluis [EMAIL PROTECTED] wrote:
Is this a problem with PostrgreSQL itself or the component in lazarus
wrapping it?
It's a problem of postgres. A transaction 'block' is started with the
sql-command 'begin', from that comand on, all queries are executed
within that transaction. Using another connection is not possible.
Unless, offcourse, you start a new connection. Or closes the transaction
(commit, rollback etc)
Please pardon me for jumping in the middle of the thread, but your
phrase made me really curious. The behaviour you described seems
to be the normal one, once you execute begin (transaction) . What
other behaviour would someone expect postgres to have ?
Several other databases have support for more then one transaction. This
means that if you want to execute a query, you have to tell in which
transaction the query should be executed. There are no real standard
sql-commands for this, but consider something like this:
connect;
begin trans1;
begin trans2;
trans1: select * from tbl1;
trans1: insert into tbl1(str) values ('Welcome');
trans2: select * from tbl1;
commit trans1;
trans2: select * from tbl1;
commit trans2;
disconnect;
This code will never show the just inserted value 'welcome'. (Default
isolation-level)
Since the insert that is done in transaction1, isn't visible for
transaction2.
Postgres doesn't support multiple transactions in one connection. So you
have to use two connections. But further it's the same.
JoJo,
Joost.
_
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Re: [lazarus] FPC question
On 4/19/06, Michael Van Canneyt [EMAIL PROTECTED] wrote: On Wed, 19 Apr 2006, Adrian Maier wrote: On 4/19/06, Joost van der Sluis [EMAIL PROTECTED] wrote: Is this a problem with PostrgreSQL itself or the component in lazarus wrapping it? It's a problem of postgres. A transaction 'block' is started with the sql-command 'begin', from that comand on, all queries are executed within that transaction. Using another connection is not possible. Unless, offcourse, you start a new connection. Or closes the transaction (commit, rollback etc) Please pardon me for jumping in the middle of the thread, but your phrase made me really curious. The behaviour you described seems to be the normal one, once you execute begin (transaction) . What other behaviour would someone expect postgres to have ? To allow several concurrent transactions. Is this implemented inside the database engine, as some special SQL commands ? Is it possible to start more transactions simultaneously from firebird's interactive utility?how does one specify that a certain SQL command has to be executed inside one transaction or another ? Interbase/Firebird allows to start several concurrent transactions in 1 connection. AFAIK Oracle and MS-SQL too (named transactions). I'm not sure about this. Oracle has named transactions, but those are just labels that are given to long-running transaction - so that they can be easier identified. Also, in Oracle it is possible that a stored procedure be executed in an 'autonomous' transaction ( i've used this once for writing a procedure that wrote debugging information to a table ; in case of error the messages would have been rolled back unless they were inserted by an autonomous transaction). But i believe that these autonomous transactions are a different beast from the feature we are talking about. This is extremely handy. I understand this. Yet, my feeling is that this feature is an interbase/firebird extension , and that it would be possible to achieve the same by using more standard features like cursors and savepoints. Adrian Maier _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Wed, 19 Apr 2006, Adrian Maier wrote: On 4/19/06, Michael Van Canneyt [EMAIL PROTECTED] wrote: On Wed, 19 Apr 2006, Adrian Maier wrote: On 4/19/06, Joost van der Sluis [EMAIL PROTECTED] wrote: Is this a problem with PostrgreSQL itself or the component in lazarus wrapping it? It's a problem of postgres. A transaction 'block' is started with the sql-command 'begin', from that comand on, all queries are executed within that transaction. Using another connection is not possible. Unless, offcourse, you start a new connection. Or closes the transaction (commit, rollback etc) Please pardon me for jumping in the middle of the thread, but your phrase made me really curious. The behaviour you described seems to be the normal one, once you execute begin (transaction) . What other behaviour would someone expect postgres to have ? To allow several concurrent transactions. Is this implemented inside the database engine, as some special SQL commands ? Yes. SET TRANSACTION Is it possible to start more transactions simultaneously from firebird's interactive utility? Yes. how does one specify that a certain SQL command has to be executed inside one transaction or another ? SELECT TRANSACTION NAME XYZ Interbase/Firebird allows to start several concurrent transactions in 1 connection. AFAIK Oracle and MS-SQL too (named transactions). I'm not sure about this. Oracle has named transactions, but those are just labels that are given to long-running transaction - so that they can be easier identified. Also, in Oracle it is possible that a stored procedure be executed in an 'autonomous' transaction ( i've used this once for writing a procedure that wrote debugging information to a table ; in case of error the messages would have been rolled back unless they were inserted by an autonomous transaction). But i believe that these autonomous transactions are a different beast from the feature we are talking about. Probably it's a restricted form. Like I said, I'm not sure about oracle and MS-SQL... This is extremely handy. I understand this. Yet, my feeling is that this feature is an interbase/firebird extension , and that it would be possible to achieve the same by using more standard features like cursors and savepoints. Interbase has those too, but you can't do what I need with that: In a server app, have 1 connection and several independent transactions within that connection. You must take into account that most commercial engines require a per-user license, so connections are 'expensive'. 1 connection with separate transactions solves this problem. There is 1 connection, but each user is in a separate transaction... Michael. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Wed, 2006-04-19 at 13:22 +0300, Adrian Maier wrote: On 4/19/06, Michael Van Canneyt [EMAIL PROTECTED] wrote: On Wed, 19 Apr 2006, Adrian Maier wrote: On 4/19/06, Joost van der Sluis [EMAIL PROTECTED] wrote: Is this a problem with PostrgreSQL itself or the component in lazarus wrapping it? It's a problem of postgres. A transaction 'block' is started with the sql-command 'begin', from that comand on, all queries are executed within that transaction. Using another connection is not possible. Unless, offcourse, you start a new connection. Or closes the transaction (commit, rollback etc) Please pardon me for jumping in the middle of the thread, but your phrase made me really curious. The behaviour you described seems to be the normal one, once you execute begin (transaction) . What other behaviour would someone expect postgres to have ? To allow several concurrent transactions. Is this implemented inside the database engine, as some special SQL commands ? Is it possible to start more transactions simultaneously from firebird's interactive utility?how does one specify that a certain SQL command has to be executed inside one transaction or another ? Interbase/Firebird allows to start several concurrent transactions in 1 connection. AFAIK Oracle and MS-SQL too (named transactions). I'm not sure about this. Oracle has named transactions, but those are just labels that are given to long-running transaction - so that they can be easier identified. Also, in Oracle it is possible that a stored procedure be executed in an 'autonomous' transaction ( i've used this once for writing a procedure that wrote debugging information to a table ; in case of error the messages would have been rolled back unless they were inserted by an autonomous transaction). But i believe that these autonomous transactions are a different beast from the feature we are talking about. Oracle's transactions are the most flexible. You can do the same thing with them as with the Firebird transactions, and far more. If you use the C-api to execute a query, you have to/can provide the transaction in which the query should get executed. I don't know if that could also be done with SQL-statements, or which statements that should be. JoJo, Joost. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Wed, 2006-04-19 at 13:36 +0300, Adrian Maier wrote:
On 4/19/06, Joost van der Sluis [EMAIL PROTECTED] wrote:
Several other databases have support for more then one transaction. This
means that if you want to execute a query, you have to tell in which
transaction the query should be executed. There are no real standard
sql-commands for this, but consider something like this:
The one thing that is unclear for me is how do you specify in which
transaction you wish to execute a particular command.
connect;
begin trans1;
begin trans2;
trans1: select * from tbl1;
Is this some kind of pseudocode, or are you saying that
trans1: select * from tbl1; is valid SQL syntax ?
No, pseudo-code, see Michaels mail for the real commands.
trans1: insert into tbl1(str) values ('Welcome');
trans2: select * from tbl1;
commit trans1;
trans2: select * from tbl1;
commit trans2;
disconnect;
This code will never show the just inserted value 'welcome'. (Default
isolation-level)
Since the insert that is done in transaction1, isn't visible for
transaction2.
Indeed, it's not visible. Therefore: the same user can see that record
in one place, and at the same time he doesn't see the record in another
place. Is this truly a good thing ?
No. I would use one transaction for one user.
Or you can decide to use one transaction for each form, or one for each
thread. That's all up to the developer.
--
Met vriendelijke groeten,
Joost van der Sluis
CNOC Informatiesystemen en Netwerken
http://www.cnoc.nl
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Re: [lazarus] FPC question
On 4/19/06, Joost van der Sluis [EMAIL PROTECTED] wrote: No, pseudo-code, see Michaels mail for the real commands. Yep, I've seen them. Interesting. It's good to know about them . Indeed, it's not visible. Therefore: the same user can see that record in one place, and at the same time he doesn't see the record in another place. Is this truly a good thing ? No. I would use one transaction for one user. This happens in a middle-tier application, i guess. Or you can decide to use one transaction for each form, or one for each thread. That's all up to the developer. I see. Just a last note (maybe this is useful for someone): When using postgresql and there are too many users, it is possible to use connection polling : http://pgpool.projects.postgresql.org/ Adrian Maier _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Wednesday 19 April 2006 04:57, Adrian Maier wrote: On 4/19/06, Joost van der Sluis [EMAIL PROTECTED] wrote: No, pseudo-code, see Michaels mail for the real commands. Yep, I've seen them. Interesting. It's good to know about them . Indeed, it's not visible. Therefore: the same user can see that record in one place, and at the same time he doesn't see the record in another place. Is this truly a good thing ? No. I would use one transaction for one user. This happens in a middle-tier application, i guess. Or you can decide to use one transaction for each form, or one for each thread. That's all up to the developer. I see. Just a last note (maybe this is useful for someone): When using postgresql and there are too many users, it is possible to use connection polling : http://pgpool.projects.postgresql.org/ Adrian Maier Since I believe I'm the guy that started this thread I think I'll take the time to explain in more detail how and why I started the thread. In the app I want to develop I would like the user to be able to have open several forms at once. As an example I could open the customer form several times and each form would be independent of each other. Each customer form could do lookups, change data etc. You see examples of what I'm describing in accounting programs. I started out attempting to use a data module. The data module solution sort of worked (although I would crash for unknown reasons) but required that the transaction control be opened and closed often as I moved from form to form and from action to action (selects, updates, deletes, inserts). Controlling a single transaction control from each form was a pain. So why not have a number of transactions available – one for each form. That's when I discovered that one connection would not allow multiple transaction. You see I was leaving the transaction active. When I opened a second form and attempted to select any data I'd get the error stating that I had an open transaction. This started me thinking why does this limitation exist? So I started asking questions. Shouldn't each transaction have it's own session. Why is it that when I do a read (select) I must have a transaction open (a begin is sent to the database engine). In the end I have been told that it is a limitation of Postgres not SQLdb. So in the end I choose to use a new connection for each form. I guess the real reason I questioned all of this was because I did not have any such limitation when using Foxpro to connect to Postgres. I could make all the reads I wanted without having to start a transaction. But I was forced to control updates, inserts, and deletes within transactions. Yes I understand that I could write a Unit that contains a routine to handle my reads: procedure GetSqlData(parameter myquery); Open the transaction; Make the select; Close the transaction; And the above started more questions. When I started experimenting with the call I noticed that my code size got larger. I would have thought just the reverse would have occurred. I became concerned when I realized that I was passing objects as parameters. So then I asked the question about how the compiler handled the call. Which is why this thread is labeled “FPC question”. I was concerned that I had missed a compiler switch or was doing it wrong. In the end I have no answer. The size of the bin is not that large (I have about 8 forms and code = approx. 15.1 megs) and it seems to run fast with calling a central routine or just having a connection for each form. Programming is a lot easier when I just add a connection for each form. But then I open lots of connections. Postgres can handle thousands of connections with little overhead. So why worry – be happy to coin a song. John _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Tuesday 18 April 2006 08:25, Alexandre Leclerc wrote: 2006/4/17, johnf [EMAIL PROTECTED]: Or is it better (what a word): sqlunit If you have a 'sqlunit' that handles all the sql stuff of you application, be object oriented in your concepts. Iwould have only one function in the sqlunit to close the sql object(s) with proper checks. If you have an sqltransaction in each form (which looks like), simple have the procedure in the form or in a descendent of the form. TMySQLForm = class(TForm) // stuff your sqltransaction object in it and the procedure. Then inherit from the TMySQLForm Another simple way is to avoid such a function for a simple task like that. You could simply execute the code sqltransaction1.active:=False; in the OnDestroy of the form. With the TMySQLForm example concept it would be a good idea too. Avoid the procedure for such a simple task. It is like bloat code ;) Best Regards. -- Alexandre Leclerc Thanks for answering. You are right the task was very simple. I used the code as an example because in fact I'm having issues with understanding the OOP involved and how the FPC compiler works. It seems that having one call would be the OOP thing to do. But I noticed that making the call increased the size of the code and I wondered if the execution speed would suffer because of the call. In general I would say that the SQLdb is not OOP in its use. PQConnections,TSQLTransactions and TSQLQuery work best if they are placed on the form and not created at runtime. I'm not sure if this is because my inexperience with FPC (the way I coded it) or because of the way SQLdb was designed (maybe the way Delphi was designed?). In the Visual FoxPro world I normally would have an object (class) that is placed on the form to handle all interaction with the data as required. But so far I don't understand how to do this with the SQLdb controls. I could create a class to create and set all the SQLdb controls in code but I don't understand how to add it (the class) to the forms. Even if I did create the class I don't see the advantage over just placing the SQLdb controls directly on the forms. OOP for OOP sake does not make much sense. Placing the TSQLTransaction on the form handles all the 'Begin' and 'Rollback' issues and infact by placing a PQConnection on each form creates a new connection to the database - therefore, the database is then responsable for any data locking issues. What could easier - I don't have to worry about record locking except within the forms access. So you can see I have questions about how data is accessed. I did notice that there is a framework that is available (started with a oT - something) for FPC. But I noticed that it's main purpose is to support different database engines with the same code base. Not what I was looking for. Anyway, I keep learning more about FPC and Lazarus daily. John _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Tue, 2006-04-18 at 10:21 -0700, johnf wrote: In the Visual FoxPro world I normally would have an object (class) that is placed on the form to handle all interaction with the data as required. But so far I don't understand how to do this with the SQLdb controls. I could create a class to create and set all the SQLdb controls in code but I don't understand how to add it (the class) to the forms. Even if I did create the class I don't see the advantage over just placing the SQLdb controls directly on the forms. OOP for OOP sake does not make much sense. Placing the TSQLTransaction on the form handles all the 'Begin' and 'Rollback' issues and infact by placing a PQConnection on each form creates a new connection to the database - therefore, the database is then responsable for any data locking issues. What could easier - I don't have to worry about record locking except within the forms access. So you can see I have questions about how data is accessed. I also read that in your wiki-article. But you can have one connection, whith several transactions bound to it. PostgreSQL doesn't support that, but SQLdb handles that for you, it creates new connection internally automatically. So you could think of 1 connection for the whole aplication, and then one transaction for each form. JoJo, Joost. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
2006/4/18, johnf [EMAIL PROTECTED]: Thanks for answering. You are right the task was very simple. I used the code as an example because in fact I'm having issues with understanding the OOP involved and how the FPC compiler works. It seems that having one call would be the OOP thing to do. But I noticed that making the call increased the size of the code and I wondered if the execution speed would suffer because of the call. In general I would say that the SQLdb is not OOP in its use. PQConnections,TSQLTransactions and TSQLQuery work best if they are placed on the form and not created at runtime. I'm not sure if this is because my inexperience with FPC (the way I coded it) or because of the way SQLdb was designed (maybe the way Delphi was designed?). With the big CPU of today a procedure call will not slow down your application that much :). But I'm from the old school on some parts of code like that. The example function you made is in my things you don't do list, except if it fulfills some OOP criterions and specific reasons that would have made such a procedure a good app/code design. :) In the very precise case you talk, if many forms are using PQConnections, TSQLTransactions and TSQLQuery, I would create a new form that implement already all these controls and functions you need. (But... see bellow.) Then I would inherit from this form. I dont' know if lazarus is yet able to do form inheritance at design time. I saw a thread some times ago that it was not yet able to do it in the editor. But in the code, it will. It requires inheritance / class creation knowledge. You could certainly find a lot of information on the web (see Delphi) if you are not very familiar with this. These are concepts not too hard to learn. As for the bd controls, it should be no problems if they are created at run time. It is probably some simple things that are missing. (I did not try the controls, I'm talking about theory here.) In the Visual FoxPro world I normally would have an object (class) that is placed on the form to handle all interaction with the data as required. But so far I don't understand how to do this with the SQLdb controls. I could create a class to create and set all the SQLdb controls in code but I don't understand how to add it (the class) to the forms. Even if I did create the class I don't see the advantage over just placing the SQLdb controls directly on the forms. OOP for OOP sake does not make much sense. Placing the TSQLTransaction on the form handles all the 'Begin' and 'Rollback' issues and infact by placing a PQConnection on each form creates a new connection to the database - therefore, the database is then responsable for any data locking issues. What could easier - I don't have to worry about record locking except within the forms access. So you can see I have questions about how data is accessed. The way to go in Delphi (and Lazarus) is to create a TDataModule and put all your DB related stuff there. Then in the Form you 'uses' the TDataModule and acces the DB aware controls from there. So you have only one central location. This is much better than my previous example bellow. (In fact, I would never do that personally; I use DataModules.) This is a very clean OOP approach, and code reuse can be potentially high and effective (and lower your app size and increase efficiency with memory, etc.) I say 'could' because it depends how you code your thing. :) Best regards. -- Alexandre Leclerc _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
2006/4/18, Joost van der Sluis [EMAIL PROTECTED]: But you can have one connection, whith several transactions bound to it. PostgreSQL doesn't support that, but SQLdb handles that for you, it creates new connection internally automatically. Do you mean TPQConnection does not support many TSQLTransaction? In Delphi I was using ODBC access and many TQuery plugged to my data provider. This was working with only one connection and working great. Was it because ODBC/BDE was handling the thing for me? Or is it reallt a TPQConnection issue? -- Alexandre Leclerc _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Tuesday 18 April 2006 11:31, Joost van der Sluis wrote: On Tue, 2006-04-18 at 10:21 -0700, johnf wrote: In the Visual FoxPro world I normally would have an object (class) that is placed on the form to handle all interaction with the data as required. But so far I don't understand how to do this with the SQLdb controls. I could create a class to create and set all the SQLdb controls in code but I don't understand how to add it (the class) to the forms. Even if I did create the class I don't see the advantage over just placing the SQLdb controls directly on the forms. OOP for OOP sake does not make much sense. Placing the TSQLTransaction on the form handles all the 'Begin' and 'Rollback' issues and infact by placing a PQConnection on each form creates a new connection to the database - therefore, the database is then responsable for any data locking issues. What could easier - I don't have to worry about record locking except within the forms access. So you can see I have questions about how data is accessed. I also read that in your wiki-article. But you can have one connection, whith several transactions bound to it. PostgreSQL doesn't support that, but SQLdb handles that for you, it creates new connection internally automatically. So you could think of 1 connection for the whole aplication, and then one transaction for each form. JoJo, Joost. I did attempt to use only one connection. But it appeared that each transaction on each form (each form has only one transaction) was not independent of each other. At least with FPC 2.1.1 (a few weeks ago). I kept getting an error suggesting I could not open a second transaction without closing the first transaction. It could be that Postgres does not support the multiple transactions per connection. Thanks, John _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
2006/4/18, Joost van der Sluis [EMAIL PROTECTED]: Delphi handled that for you, yes. Just like SQLdb does. ODBC doesn't support more than one transaction for a connection, just like PostgreSQL. Very interesting, I never payed attention to that. I have an app in D3/BDE/ODBC/PostgreSQL8.x and will look at the behaviour this week-end. (Look at multiple connections to the PostgreSQL server). In fact, I'm not scandalized by that; this is ok. If a thread/dbconnection crashes this will not affect the whole working of the program/db. So there are advantages to that behaviour. Disaventage is potentially too many connections per client (and to the server). But, at that point, better software design can be achieve. Thank you for the information Joost. -- Alexandre Leclerc _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Tuesday 18 April 2006 13:42, Marc Santhoff wrote: Am Dienstag, den 18.04.2006, 21:29 +0200 schrieb Joost van der Sluis: On Tue, 2006-04-18 at 14:43 -0400, Alexandre Leclerc wrote: 2006/4/18, Joost van der Sluis [EMAIL PROTECTED]: But you can have one connection, whith several transactions bound to it. PostgreSQL doesn't support that, but SQLdb handles that for you, it creates new connection internally automatically. Do you mean TPQConnection does not support many TSQLTransaction? 'But you can have one connection, whith several transactions bound to it.' So you can. Only PostgreSQL can't, so SQLDdb handles it. May I ask: Is this a problem with PostrgreSQL itself or the component in lazarus wrapping it? I'm planning to use PG in the near future, but this may influence my decision ... TIA, Marc I can't answer your question directly. But I can provide a little information about what I have added to this discussion. First let me say that I have always used only one connection to a database engine and controlled all of my transactions in code in the past (just to let you know where I'm coming from). But with FPC I was not able to use just one connection to the database. At first I considered this fact to be a problem. But then I reconsidered. Yes, it is true if my user opens 10 forms I will have ten connections and if I have 100 users I will have 1000 connections open. This of course sounded like a lot. But then I realized that today Postgres can handle thousands of connections without issue. In fact 1000 connections uses only 50K of extra ram. With todays fast CPU's controlling 1000 connections is nothing. But what about the time to open each connection? On a LAN I doubt it amounts to much. On my LAN we are talking about micro-seconds per connection (at least that is what is reported in the log). But on a dial-up - Maybe! So in the end I guess it really doesn't matter. BTW in my app I doubt if my users will have ten forms open at the same time. Also in my app I close the connection each time I close a form. One nice thing as result of using a connection per form - I no longer attempt to control the locking in anyway. I let Postgres use it's record locking schema. I just use a try to catch the error if there is a locking issue. So far I can not create any locking issues even in code. Postgres is faster than I can update the data. Hope this helps! John _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
On Tue, 2006-04-18 at 22:42 +0200, Marc Santhoff wrote: Am Dienstag, den 18.04.2006, 21:29 +0200 schrieb Joost van der Sluis: On Tue, 2006-04-18 at 14:43 -0400, Alexandre Leclerc wrote: 2006/4/18, Joost van der Sluis [EMAIL PROTECTED]: But you can have one connection, whith several transactions bound to it. PostgreSQL doesn't support that, but SQLdb handles that for you, it creates new connection internally automatically. Do you mean TPQConnection does not support many TSQLTransaction? 'But you can have one connection, whith several transactions bound to it.' So you can. Only PostgreSQL can't, so SQLDdb handles it. May I ask: Is this a problem with PostrgreSQL itself or the component in lazarus wrapping it? It's a problem of postgres. A transaction 'block' is started with the sql-command 'begin', from that comand on, all queries are executed within that transaction. Using another connection is not possible. Unless, offcourse, you start a new connection. Or closes the transaction (commit, rollback etc) JoJo, Joost. _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Am Dienstag, den 18.04.2006, 23:28 +0200 schrieb Joost van der Sluis: On Tue, 2006-04-18 at 22:42 +0200, Marc Santhoff wrote: Am Dienstag, den 18.04.2006, 21:29 +0200 schrieb Joost van der Sluis: 'But you can have one connection, whith several transactions bound to it.' So you can. Only PostgreSQL can't, so SQLDdb handles it. May I ask: Is this a problem with PostrgreSQL itself or the component in lazarus wrapping it? It's a problem of postgres. A transaction 'block' is started with the sql-command 'begin', from that comand on, all queries are executed within that transaction. Using another connection is not possible. Unless, offcourse, you start a new connection. Or closes the transaction (commit, rollback etc) I see. Problems or at least unusual design approaching when regarding datamodules ... Thank you, Marc _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
Re: [lazarus] FPC question
Am Dienstag, den 18.04.2006, 14:27 -0700 schrieb johnf: Yes, it is true if my user opens 10 forms I will have ten connections and if I have 100 users I will have 1000 connections open. This of course sounded like a lot. But then I realized that today Postgres can handle thousands of connections without issue. In fact 1000 connections uses only 50K of extra ram. With todays fast CPU's controlling 1000 connections is nothing. But what about the time to open each connection? On a LAN I doubt it amounts to much. On my LAN we are talking about micro-seconds per connection (at least that is what is reported in the log). But on a dial-up - Maybe! So in the end I guess it really doesn't matter. Thanks to your report I see no problems in the number of connections at all but I fear design trouble in writing the persistance layer in a way independant from the database without having too much code dealing with a special kind of database - but that was only a dream, I think. ;) BTW in my app I doubt if my users will have ten forms open at the same time. Also in my app I close the connection each time I close a form. One nice thing as result of using a connection per form - I no longer attempt to control the locking in anyway. I let Postgres use it's record locking schema. I just use a try to catch the error if there is a locking issue. So far I can not create any locking issues even in code. Postgres is faster than I can update the data. I'll have to deal with multiple transactions, sort of bulk updates together with XML-RDB-mapping, this will be important when coupling to the client app(s) has to be done. But all of this is in it's early planning stages, I haven't evaluated native XML databases yet. Hope this helps! It does, thank you. Regards, Marc _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
[lazarus] FPC question
Hi, I have code like: procedure CloseDataAccess; begin self.sqltransaction1.active:=False; end; in each form (might have 20 forms). Or is it better (what a word): sqlunit procedute CloseDataAccess(sender:tsqltransaction); begin sender.active:=False; end; And call the CloseDataAccess for each form. It would seem that the compiler would have only one routine in memory if I used the 'sqlunit'. But what does it save? John _ To unsubscribe: mail [EMAIL PROTECTED] with unsubscribe as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
