RE: Selective Update of fields depending on values in object

[Rashmi Dave]

Hi Jeff,   I started out thinking exactly the same and so did not see a problem with the entire update. However, there are some fields in the table that are not getting displayed. Now here, I need to fire a select, find out what the current value is, and then put that value in the parameter object. Which basically means an additional select per update.   I will write a custom update for the last login date.  Thanks a lot for your help.   Regards ~Rashmi   From: Jeff Butler [mailto:[EMAIL PROTECTED] Sent: Wednesday, February 15, 2006 9:10 PM To: user-java@ibatis.apache.org Subject: Re: Selective Update of fields depending on values in object   Hi Dave,   I understand the "last login date" requirement - I would write a custom update for that requirement.   For the other, I've always taken a different stance on these kinds of things.  It seems easier to me to update the whole record that do do the dirty checking you would need to do to accomplish the selective update.  The problem is this - how do you know what fields have changed?  If this is a web app, then you would need to read the old record and do a field by field check (or use some kind of _javascript_ hack to set dirty flags).  If it's not a web app, then its certainly easier to manage the state - but you would still have to do the dirty check or set dirty flags somehow.  I've always thought it was easier just to update the entire record.   Just my thoughts - your experience may be different.   Jeff Butler   On 2/15/06, Rashmi Dave <[EMAIL PROTECTED]> wrote: Hi Jeff,   I have a form – Update Profile of the User. Here, I would like to update only those columns that have changed.   Also, when my user logs in, I want to update only the Last_Login_date field of the user table. This is why I need it.   Hope this clarifies.   Regards ~Rashmi   From: Jeff Butler [mailto: [EMAIL PROTECTED]] Sent: Wednesday, February 15, 2006 7:25 PM To: user-java@ibatis.apache.org Subject: Re: Selective Update of fields depending on values in object   Hi Dave,   1. You don't need to regenerate the maps if all you're changing is NOT NULL to NULL.  Abator doesn't care about the nullability of a column.  But regenerating the maps shouldn't be a big issue anyway - Abator was designed so you could run it repeatedly without losing anything extra you've added.   2. You are correct that the update statement updates all columns.  You'll need to write custom update statements if you want to update a subset of the columns.   I think it is unusual to do selective column updates if you are working with anything close to a rich domain model - I've never had that requirement on any of my projects.  That's why I didn't add support for it in Abator.  I suppose it wouldn't be that difficult to add if there is a general feeling that it's needed.  Does anyone else have any thoughts about this?   Jeff Butler   On 2/15/06, Rashmi Dave < [EMAIL PROTECTED]> wrote: Hi All, We are using Abator generated SQL Map configuration files. I have two questions 1. It turns out that a column in a table that I thought is NOT NULL, should be a NULL column. I need to change the schema. Now do I need to re-generate the SQL Maps again? (Please say I don't have to!!) Is there any information regarding NULL/NOT NULL property stored? 2. The update query generated by Abator makes it compulsory for us to update all columns in the table. What do I need to do to selectively update? Can I somehow reuse the same update generated and avoid writing a different update query per column? I hope this question isn't an obvious one. Kindly point me to what feature I need to read the docs about if it is... Thanks in advance. Regards ~Rashmi