A few record locking questions

[Reva]

I read in the documentation that it's a good idea to turn off Windows opportunistic record locking if you have an A5 multi-user app running on XP or Win2003 server. I'm concerned about doing this because I have people using a SQL db with a non-A5 app and I don't know how this might affect them. Does anyone have any experience with this?

Also, I have a form based on a set. The users are working with different parent records, so most of the tables in the set would not be triggering a record locked error. But there are a couple of tables, one linked to the parent & one to the child, that are reference tables. They basically provide descriptions for numeric codes, prevent the user from entering an invalid code, and define some conditional processing. The details are irrelevant, but the point is that multiple users may be accessing these tables but NOBODY is ever writing to them in this particular form. Since the users have occasionally gotten record locked errors, I'd like to make these 2 tables read-only so that no locking would happen. I just can't seem to find an action script to make a table readonly. It's easy to make a field readonly, and even an entire browse, but not a table. I'm sure there must be a way to do this...

And finally, if I created a shadow db on the user pc's, would that have any affect on record locking?

[Reva]

Re: A few record locking questions

Can anyone offer any info on this? The record locking problem in this app is really getting in the way and I'm not sure where to go with this. I've tried the documentation but I don't see anything that describes my situation.

[Raymond Lyons]

Re: A few record locking questions

I am going to respond only because no one else has (i.e., I am no authority on your main question).

I read in the documentation that it's a good idea to turn off Windows opportunistic record locking if you have an A5 multi-user app running on XP or Win2003 server. I'm concerned about doing this because I have people using a SQL db with a non-A5 app and I don't know how this might affect them. Does anyone have any experience with this?

I have no experience with this issue but it is a very good question. If you find an answer, let us know (it is essentially a SQL DB question, assuming both DB's were on the same server).

Also, I have a form based on a set. The users are working with different parent records, so most of the tables in the set would not be triggering a record locked error. But there are a couple of tables, one linked to the parent & one to the child, that are reference tables. They basically provide descriptions for numeric codes, prevent the user from entering an invalid code, and define some conditional processing. The details are irrelevant, but the point is that multiple users may be accessing these tables but NOBODY is ever writing to them in this particular form. Since the users have occasionally gotten record locked errors, I'd like to make these 2 tables read-only so that no locking would happen. I just can't seem to find an action script to make a table readonly. It's easy to make a field readonly, and even an entire browse, but not a table. I'm sure there must be a way to do this...

Why can't you just set the form properties (in design mode) to restrict entering or changing records? Then if you wanted you could create a password protected button on your form, use xbasic and put in the following:

topparent.restrict_enter=.f.
topparent.restrict_change=.f.

Then users would not be able to make any changes or enter new records unless they know the password for your button. Unrestricting these things would be effective only for the one user and would go back to be restricted for that user the next time they open the form. If you wanted you could even create another button to put the restrictions back (=.t.) for the user who undid them--could even be on the same button if you wanted to get semi-clever.

As for making the table read only, I know of no way to do this even using xbasic (though there is bound to be a way!). Manually you could get to the dbf table in whatever Windows utility you use to get to files (e.g., Windows Explorer), right click on the file and make it read only. Seems unwieldy though. I would do what I suggested at the form level.

And finally, if I created a shadow db on the user pc's, would that have any affect on record locking?

None.

Ray

[Reva]

Re: A few record locking questions

Thanks for your reply, Ray. The problem is that the users need to be making changes all the time. That's the point of the app. The only table in the set that they DON'T need to change is also the only one where they're likely to be accessing the same record & locking each other out. That table is only used for calculations & as a pull-down. There's no way for them make any changes to it in the form. It seems that there ought to be a way to specify that this one table shouldn't be locked, but I can't find it. Interestingly enough, we didn't have this problem with this same app in version 8, so now I'm wondering if this might actually be a bug?

[MikeC]

Re: A few record locking questions

Reva,
If this is for sure the way you want to do this and no xbasic function is present then making a file (or folder with files) readonly is fairly easy to do. A .vbs file can be created and then with xbasic opened to make whatever file is indicated within the vbs file a readonly....or whatever attributes you would want really. I can do it in just a minute or two if you know the path to the file---a bit longer if you need it to be a bit more generic with a5.get_path() (or a5.get_master_path() for network server).

The one time I figured this out for a similar case Alpha ended up having a function already for it and do believe a different way ended up being used instead. Just let me know.

[Reva]

Re: A few record locking questions

Hi Mike,
The file will always be in the same directory with the other files, but I do need that directory to be able to change, just so that I can test things on my laptop. So if what you'd be writing can't just default, I guess you'd need to get the network path since this is a network setup. It seems to me that there ought to be an A5 function for this, but I just haven't been able to find it. I'd love to see your script. The table name is CallResult. Do you need more info from me?

[Raymond Lyons]

Re: A few record locking questions

Thanks for your reply, Ray. The problem is that the users need to be making changes all the time. That's the point of the app. The only table in the set that they DON'T need to change is also the only one where they're likely to be accessing the same record & locking each other out. That table is only used for calculations & as a pull-down. There's no way for them make any changes to it in the form. It seems that there ought to be a way to specify that this one table shouldn't be locked, but I can't find it. Interestingly enough, we didn't have this problem with this same app in version 8, so now I'm wondering if this might actually be a bug?

Sorry, I misunderstood your issue. It sounds like those one or two tables do not really need to be part of the set (maybe a separate lookup for the pull down and/or just pull values into variables to use for other things). However, this should not be necessary, especially if there were no problems using v8. You could send off a sample app to Alpha, but if this is something that can only happen when several users are using it, I doubt Sewlyn and crew are going to be able to find the problem.

Ray

[MikeC]

Re: A few record locking questions

Reva,

It sounds like you just need to be able to make the table read only on your server correct? And on your laptop. In other words, if the table is to be set to read only on the computer you will be currently using then this would do it I believe. Place wherever, button, autoexec, etc...

 
dim dbpath as c
dbpath=a5.Get_Path()+"\\"
dim fil as p
 
fil=file.create(dbpath+"VB_Read_Only.vbs",FILE_RW_EXCLUSIVE)
fil.write_line("Const ReadOnly = 1")
fil.write_line("Set objFSO = CreateObject(\"Scripting.FileSystemObject\")")
fil.write_line("Set objFile = objFSO.GetFile(\""+dbpath+"CallResult.dbf\")")
fil.write_line("If Not objFile.Attributes AND ReadOnly Then")
fil.write_line("    objFile.Attributes = objFile.Attributes XOR ReadOnly")
fil.write_line("End If")
''Next is to have the .vbs file actually change the readonly attribute.
xbasic_wait_for_idle()''used as created in version 5....ui_yield() could most likely to be used in version 8
sys_open(dbpath+"VB_Read_Only.vbs")''this acts just like if you doubleclicked on the file which plays the .vbs script.
fil.flush()
fil.close()

If you would want to just have the script toggle the read only value then change the

fil.write_line("If Not objFile.Attributes AND ReadOnly Then")
fil.write_line("    objFile.Attributes = objFile.Attributes XOR ReadOnly")
fil.write_line("End If")

to simply

fil.write_line("    objFile.Attributes = objFile.Attributes XOR ReadOnly")