Qt-interest Archive, November 2006
[Qt 4.2] Using SQLite in memory with Qt Resource System
Message 1 in thread
Hi all,
I have some pretty static data that I want to ship with my app (relates to
postcode formats / country names). I can currently extract the data into my
programme from a separate sqlite3 database on the users PC. Now I want to
hide the data to prevent inadvertent loss.
I am interested in the in memory option (setDatabaseName(":memory:"). So far
I have seen examples where a table is created this way with values inserted
using programme code (e.g. Cached Table Example in 4.2 docs).
Is there a direct way of getting an existing sqlite3 database into memory
using e.g. resource system
myapp.qrc ...headerstuff....<file>/config/database.db</file>....footer stuff
and some other code to associate the particular database into memory?
If there is no direct way to do this, is it possible to create the relevant
tables in memory using SQL and then importing the data from an embedded csv?
[I am happy with table creation idea but looking for guidance on importing
data from csv once table is ready].
Any help much appreciated.
Regards,
Amit
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Message 2 in thread
> Is there a direct way of getting an existing sqlite3 database into memory
http://www.mail-archive.com/sqlite-users@xxxxxxxxxx/msg15904.html
Entirely sqlite specific, of course.
Micha
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Message 3 in thread
Micha,
many thanks for the excellent answer to the specific item.
I'd recommend the presentation referenced below to anyone looking at sqlite
for the first time.
If anyone knows of a way of reading from (e.g. csv) into sqlite from within Qt
I'm still curious. I can do it using meta commands issued at the sqlite
prompt. Micha's answer deals well with getting from sqlite into sqlite in
memory, but does not seem to allow for hiding the data in the executable.
Thanks,
Amit
On Thursday 02 November 2006 11:25, Michael Bieber wrote:
> > Is there a direct way of getting an existing sqlite3 database into memory
>
> http://www.mail-archive.com/sqlite-users@xxxxxxxxxx/msg15904.html
>
> Entirely sqlite specific, of course.
>
> Micha
>
>
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Message 4 in thread
amit wrote:
> Micha,
>
> many thanks for the excellent answer to the specific item.
>
> I'd recommend the presentation referenced below to anyone looking at sqlite
> for the first time.
>
> If anyone knows of a way of reading from (e.g. csv) into sqlite from within Qt
> I'm still curious. I can do it using meta commands issued at the sqlite
> prompt. Micha's answer deals well with getting from sqlite into sqlite in
> memory, but does not seem to allow for hiding the data in the executable.
>
> Thanks,
>
> Amit
If you have your data prepared once in a sqlite database, you could dump
that database into a textfile (using the .dump meta command), and pack
that textfile into the Qt resource file.
Your application could then get a number of SQL commands from the
resource and issue them to a ':memory:' sqlite database.
/eno
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Message 5 in thread
On Thursday 02 November 2006 16:35, troll@xxxxxxxxxxxx wrote:
Great - sounds promising. Understand first para...not at all sure how to do
second bit.
Are you suggesting something like "INSERT ....FROM ...'myfile.csv' (which I
didn't think sqlite supports)? Or have I missed your meaning?
A
>
> If you have your data prepared once in a sqlite database, you could dump
> that database into a textfile (using the .dump meta command), and pack
> that textfile into the Qt resource file.
>
> Your application could then get a number of SQL commands from the
> resource and issue them to a ':memory:' sqlite database.
>
> /eno
>
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> To unsubscribe - send a mail to qt-interest-request@xxxxxxxxxxxxx with
> "unsubscribe" in the subject or the body. List archive and information:
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Message 6 in thread
amit wrote:
> On Thursday 02 November 2006 16:35, troll@xxxxxxxxxxxx wrote:
>
> Great - sounds promising. Understand first para...not at all sure how to do
> second bit.
>
> Are you suggesting something like "INSERT ....FROM ...'myfile.csv' (which I
> didn't think sqlite supports)? Or have I missed your meaning?
I don't know how to get the CSV file into a database, but I remember you
said you would know how to do that. So what you would do is
a) create a database, using the sqlite commandline tool
b) fill it with the vaues from your CSV-file
c) dump that into a file.
That file would then contain a series of SQL statements.
You add that file to your resource. After that you can access the SQL
statements from within the Qt app, where you can rebuild the database in
memory from exactly these SQL statements, and use it.
However, whenever you change the underlying data you need to do a), b)
and c) and then rebuild your application.
/eno
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Message 7 in thread
On Thursday 02 November 2006 23:14, troll@xxxxxxxxxxxx wrote:
Ah. I think this is the crucial bit. I hadn't appreciated that the dump
process would put the SQL as well as the values into the output. Will try
Monday and post outcome.
Thanks again.
A
>
> That file would then contain a series of SQL statements.
>
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