Re: OleDb delays commits and unlocks?
- From: "Cor Ligthert[MVP]" <notmyfirstname@xxxxxxxxx>
- Date: Wed, 23 Apr 2008 05:52:44 +0200
John,
From your description I was not sure if you had to update datarows or onlyto insert.
As you state it now probably a simple merge can do the job (as long as you use the same tablenames and the same columnnames).
Why avoid simple tools for simple jobs.
Like you write it, it seems to me that you want to use simple tools for difficult problems and more basic tools for difficult jobs, as I try to say it in an anology.
It looks that you are using a stappler to build a house and a hammer with nails to put some papers together.
Cor
"John W." <JohnW@xxxxxxxxxxxxxxxxxxxxxxxxx> schreef in bericht news:21CBB04B-1050-4167-BCED-4868EE839454@xxxxxxxxxxxxxxxx
I avoided using DataAdapters since (1) the operations I needed were so basic,
(2) I don't feel very comfortable with them, and (3) with the exception of
two tables, I don't need to have the updated tables in memory--only in the
file. (Those two tables are used to reconcile several foreign key columns in
various tables.) CommandBuilder lost favor with me a long time ago when I
found that it couldn't handle half of what I wanted it to do. (I don't
remember the specifics, but I do remember the disappointment.) The two tables
in Problem 2 should be among the simplest to handle. One of the new records
is always the same, and the other varies only slightly. Two INSERT commands
and I'm done, without the overhead of the DataAdapter.
"Cor Ligthert[MVP]" wrote:
Johh,
Why not simple use a DataAdapter to update as you tells that it is a single
non related table than it should be a piece of cake.
(You can then probably simple use the commandbuilder)
Cor
"John W." <JohnW@xxxxxxxxxxxxxxxxxxxxxxxxx> schreef in bericht
news:6A447E4E-19FE-403A-A8CE-43C22AF2904F@xxxxxxxxxxxxxxxx
> I've seen other posts with similar problems, but no solutions. I have > two
> hair-pulling dilemmas that have been frustrating me for months now. Is
> there no solution? (C#.NET, Framework 2.0, Jet OleDb 4.0)
>
> The general goal is to read one MDB file and copy relevant info into
> another MDB file (copied from an empty template), replacing the old
> file with the new file. DataAdapters are used only to read (or > re-read)
> the data from the file into the in-memory DataTable. All data INSERTs
> and UPDATEs are done with OleDbCommand.ExecuteNonQuery().
>
> Problem 1: To retain the original version of the file, the process
> requires two rename operations. The first renames the original file.
> The second renames the new file to have the original file's name. Half
> the files I process do this OK. The other half fail on one of the > renames,
> claiming that the file is still locked by another process. Checking > the
> directory just prior to the rename attempt confirms that the
> corresponding LDB file still exists when the rename fails and doesn't
> exist when it succeeds. I've gone so far as to put all the data > copying
> into a separate Main and invoking it with a Process.Start() so that the
> locking process has to be terminated before I attempt the rename. No
>dice. Aaaaargh!
>
> Problem 2: In the last-called method of the copy process, one new > record
> is written to each of two empty tables. After that, a message is > written to
> a log file, the method returns, and the OleDbConnection is closed. All > of
> that occurs in about a dozen lines of code. This works almost all the > time,
> except on one of my test files. With that file, the first inserted row
> appears in the output mdb file, but the second one does not! There is
> nothing particularly unusual about this file; other test files have
> identical structures. The tables involved are new tables, not present > in
> the source data file, and every test file requires that these two rows > be
> created. No errors are reported by the INSERTs or any other statement;
> it just doesn't get committed to the table. Double-Aaaaargh!!
.
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