Data integrity problem with sqlite3 - solved

Frank Millman frank at chagford.com
Tue Aug 11 15:17:44 CEST 2015


"Frank Millman"  wrote in message news:mqcmie$po9$1 at ger.gmane.org...

> Hi all
>
> I have a 'data integrity' problem with sqlite3 that I have been battling 
> with for a while. I have not got to the bottom of it yet but I do have 
> some useful info, so I thought I would post it here in the hope that 
> someone with some knowledge of the internals of the python sqlite3 module 
> can throw some light on it.

Oops, I have just spotted my mistake.

There are times when I want to issue a SELECT statement with a lock, as it 
will be followed by an UPDATE and I do not want anything to change in 
between.

MS SQL Server allows you to add 'WITH (UPDLOCK)' to a SELECT statement, 
PostgreSQL allows you to add 'FOR UPDATE'.

I could not find an equivalent for sqlite3, but in my wisdom (this was some 
time ago) I decided that issuing a 'BEGIN IMMEDIATE' would do the trick.

I had not anticipated that this would generate an implied COMMIT first, but 
it makes sense, and this is what has bitten me. Now I must try to figure out 
a better solution.

Apologies for any wasted time.

Frank








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