February 3rd, 2004 02:21 AM
Client-Server Database Question...
Is it possible that there would be conflict in server-side database when 2 or more clients send data at the same time??? is this situation possible??? should i make a code to schedule incoming data??? PLeaase HELP!!!!!
February 3rd, 2004 02:31 AM
What database engine? I don't know of any database issues. However, depending on the way the network is setup (repeating devices, switching fabric, transmission speed) you could be experiencing data collisions.
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February 3rd, 2004 06:56 AM
Hi this might be irrelevant, but it is the systems design/development view (applications software & database design) I will now put on my systems architect's hat.
There are two issues that I am aware of:
1. Object locking
2. Record locking
Any database worthy of the name will allow multiple users to access records in read only mode. Microsoft Access (hardly the strongest growth in the vinyard ) for example will warn you if someone has opened a record in "edit" mode and asks you if you want to make a copy of the record as it stands. By and large I would say that opening records should not be a problem.
The issue is in creation, updating and deleting? (remember the CRUD matrix )
Two people must not be allowed to create or update the same record at the same time, otherwise you have anarchy.
Deletion is a slightly different problem? If someone is trying to update a record at the same time as someone is trying to delete it, then there is a serious flaw in your business process!
So my basic conclusion is that if a record is being accessed in "edit" mode it should be locked from anything other than read only, and in some cases totally locked.
Object locking is a different matter. Here the entire database or a table in it is locked. It can be a total lock, where all access is denied (other than the user working on it), or a partial lock.generally to allow people to read records not being edited.
Your database engine should handle data entry such that each item gets a unique key.
You need to set rules for CRUD, but your database should handle arrival sequencing on its own.
Without more details of your requirements that is about all I can suggest.
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February 11th, 2004 11:33 AM
Thanx for your insights....
So Data collision is really possible ?
And database engines does not automatically correct this possible errorsS?
OK thnX again.....