On Wed, 21 Apr 2004, Lloyd thomas wrote:
>Forgive my ignorance, I have yet to use a transaction and therefore can you
>give me an example.
Transactions are simply SQL statements bounded by a begin/commit pair, or
begin/rollback if the transaction is to be aborted:
begin transaction;
[do something]
commit transaction;
If [do something] is a single select, then you don't need the
begin/commit. You need the begin/commit if you have multiple selects, to
prevent the database changing underneath you in between select statements.
You can play with transactions simply from the sqlite command line tool.
Any decent SQL guide or web page should explain transactions.
>
>Lloyd
>----- Original Message -----
>From: "Christian Smith" <[EMAIL PROTECTED]>
>To: "Lloyd thomas" <[EMAIL PROTECTED]>
>Cc: <[EMAIL PROTECTED]>
>Sent: Wednesday, April 21, 2004 3:27 PM
>Subject: Re: [sqlite] Backing up data by date
>
>
>> On Tue, 20 Apr 2004, Lloyd thomas wrote:
>>
>> >Which is the best way to backup rows which meet a certain date criteria?
>> >ie WHERE data is <= '2003-11-20'.
>> >Would I need to select and save the data to a temporary table and then
>DUMP the temp table.
>> >
>>
>> Just begin a transaction to get a snapshot of the database, then dump the
>> data within the transaction. No temporary table needed. Will lock the
>> database, but it is the only way to ensure a consistent view unless you
>> are saving data from a single table or view, in which case you won't need
>> the transaction.
>>
>> Christian
>>
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